init

2025-12-18 01:30:52 +01:00
commit 6438660b03
78 changed files with 14230 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,34 @@
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+node_modules/
+
+.env
+.env.local
+.env.*.local
+zen_kanji_js/.env
+zen_kanji_js/client/.env
+zen_kanji_js/client/.env.android
+
+dist/
+dist-ssr/
+*.local
+
+.vscode/*
+!.vscode/extensions.json
+.idea/
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
+
+.DS_Store
+Thumbs.db
+
+coverage/
+
+zen_kanji_js/client/android/
--- a/README.md
+++ b/README.md
--- a/client/.env.android
+++ b/client/.env.android
@@ -0,0 +1,2 @@
+VITE_API_URL=http://10.0.2.2:3000
+CAP_ENV=dev
--- a/client/.gitignore
+++ b/client/.gitignore
@@ -0,0 +1,2 @@
+node_modules
+.env
--- a/client/Dockerfile
+++ b/client/Dockerfile
@@ -0,0 +1,17 @@
+FROM node:24-alpine AS dev-stage
+WORKDIR /app
+COPY package*.json ./
+RUN npm install
+COPY . .
+EXPOSE 5173
+CMD ["npm", "run", "dev", "--", "--host"]
+
+FROM dev-stage AS build-stage
+ARG VITE_API_URL
+ENV VITE_API_URL=$VITE_API_URL
+RUN npm run build
+
+FROM nginx:stable-alpine AS production-stage
+COPY --from=build-stage /app/dist /usr/share/nginx/html
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]
--- a/client/capacitor.config.js
+++ b/client/capacitor.config.js
@@ -0,0 +1,30 @@
+/// <reference types="@capacitor/cli" />
+require('dotenv').config();
+
+const isDev = process.env.CAP_ENV === 'dev';
+
+const config = {
+	appId: "com.zenkanji.app",
+	appName: "Zen Kanji",
+	webDir: "dist",
+	server: {
+		androidScheme: isDev ? "http" : "https",
+		cleartext: isDev
+	},
+	plugins: {
+		Keyboard: {
+			resize: "body",
+			style: "dark",
+			resizeOnFullScreen: true
+		},
+		SplashScreen: {
+			launchShowDuration: 2000,
+			backgroundColor: "#1e1e24",
+			showSpinner: false
+		}
+	}
+};
+
+console.log(`⚡️ Capacitor Config loaded for: ${isDev ? 'DEVELOPMENT (http)' : 'PRODUCTION (https)'}`);
+
+module.exports = config;
--- a/client/eslint.config.js
+++ b/client/eslint.config.js
@@ -0,0 +1,69 @@
+import js from '@eslint/js';
+import globals from 'globals';
+import pluginVue from 'eslint-plugin-vue';
+import pluginVuePug from 'eslint-plugin-vue-pug';
+import pluginJsonc from 'eslint-plugin-jsonc';
+
+export default [
+	{
+		ignores: [
+			'**/node_modules/**',
+			'**/dist/**',
+			'**/android/**',
+			'**/coverage/**',
+			'**/*.min.js'
+		]
+	},
+
+	js.configs.recommended,
+	{
+		languageOptions: {
+			ecmaVersion: 'latest',
+			sourceType: 'module',
+			globals: {
+				...globals.browser,
+				...globals.node,
+				...globals.es2021
+			}
+		},
+		rules: {
+			'no-unused-vars': 'warn',
+			'no-console': process.env.NODE_ENV === 'production' ? 'warn' : 'off',
+			'no-debugger': process.env.NODE_ENV === 'production' ? 'warn' : 'off'
+		}
+	},
+
+	...pluginVue.configs['flat/recommended'],
+	{
+		files: ['*.vue', '**/*.vue'],
+		plugins: {
+			'vue-pug': pluginVuePug
+		},
+		languageOptions: {
+			parser: pluginVue.parser,
+			parserOptions: {
+				parser: js.configs.recommended.parser,
+				ecmaVersion: 'latest',
+				sourceType: 'module',
+			}
+		},
+		rules: {
+			'vue/multi-word-component-names': 'off',
+			'vue/require-default-prop': 'off',
+			'vue/html-indent': ['error', 2],
+			'no-unused-vars': 'off',
+			'vue/component-name-in-template-casing': ['error', 'PascalCase', {
+				registeredComponentsOnly: true,
+				ignores: []
+			}]
+		}
+	},
+
+	...pluginJsonc.configs['flat/recommended-with-jsonc'],
+	{
+		files: ['*.json', '**/*.json'],
+		rules: {
+			'jsonc/sort-keys': 'off',
+		}
+	}
+];
--- a/client/index.html
+++ b/client/index.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+	<meta charset="UTF-8" />
+	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
+	<title>Zen Kanji</title>
+	<link rel="icon" type="image/x-icon" href="/assets/favicon.ico">
+</head>
+
+<body>
+	<div id="app"></div>
+	<script type="module" src="/src/main.js"></script>
+</body>
+
+</html>
--- a/client/package-lock.json
+++ b/client/package-lock.json
--- a/client/package.json
+++ b/client/package.json
@@ -0,0 +1,47 @@
+{
+	"name": "zen-kanji-client",
+	"version": "0.0.0",
+	"type": "module",
+	"scripts": {
+		"lint": "eslint .",
+		"lint:fix": "eslint . --fix",
+		"lint:style": "stylelint \"**/*.{css,scss,vue}\"",
+		"lint:style:fix": "stylelint \"**/*.{css,scss,vue}\" --fix",
+		"dev": "vite",
+		"build": "vite build",
+		"build:android": "vite build --mode android",
+		"preview": "vite preview"
+	},
+	"dependencies": {
+		"@capacitor/android": "^8.0.0",
+		"@capacitor/core": "^8.0.0",
+		"@mdi/font": "^7.3.67",
+		"capacitor": "^0.5.6",
+		"i18n": "^0.15.3",
+		"pinia": "^3.0.4",
+		"pug": "^3.0.3",
+		"vue": "^3.3.4",
+		"vue-i18n": "^11.2.2",
+		"vue-pug": "^1.0.2",
+		"vue-pug-plugin": "^2.0.4",
+		"vue-router": "^4.2.5",
+		"vuetify": "^3.4.0"
+	},
+	"devDependencies": {
+		"@capacitor/cli": "^7.4.4",
+		"@eslint/js": "^9.39.2",
+		"@vitejs/plugin-vue": "^6.0.3",
+		"dotenv": "^17.2.3",
+		"eslint": "^9.39.2",
+		"eslint-plugin-jsonc": "^2.21.0",
+		"eslint-plugin-vue": "^9.33.0",
+		"eslint-plugin-vue-pug": "^0.6.2",
+		"globals": "^16.5.0",
+		"sass": "^1.97.0",
+		"stylelint": "^16.26.1",
+		"stylelint-config-recommended-vue": "^1.6.1",
+		"stylelint-config-standard-scss": "^16.0.0",
+		"vite": "^7.3.0",
+		"vue-eslint-parser": "^9.4.3"
+	}
+}
--- a/client/src/App.vue
+++ b/client/src/App.vue
@@ -0,0 +1,348 @@
+<template lang="pug">
+  v-app.zen-app
+    v-navigation-drawer(
+      v-model="drawer"
+      temporary
+      location="right"
+      color="#1e1e24"
+      class="border-none"
+      width="280"
+    )
+      .d-flex.flex-column.h-100.pa-4
+        .d-flex.align-center.mb-6.px-2
+          img.mr-3(:src="logo" height="32" width="32" alt="Logo")
+          span.text-h6.font-weight-bold {{ $t('nav.menu') }}
+
+        v-list.pa-0(nav bg-color="transparent")
+          v-list-item.mb-2(
+            to="/"
+            rounded="lg"
+            :active="$route.path === '/'"
+          )
+            template(v-slot:prepend)
+              v-icon(color="#00cec9" icon="mdi-view-dashboard")
+            v-list-item-title.font-weight-bold {{ $t('nav.dashboard') }}
+
+          v-list-item.mb-2(
+            to="/collection"
+            rounded="lg"
+            :active="$route.path === '/collection'"
+          )
+            template(v-slot:prepend)
+              v-icon(color="#00cec9" icon="mdi-bookshelf")
+            v-list-item-title.font-weight-bold {{ $t('nav.collection') }}
+
+        v-divider.my-4.border-subtle
+
+        .d-flex.flex-column.gap-2
+          v-btn.justify-start.px-4(
+            variant="text"
+            block
+            color="grey-lighten-1"
+            @click="showSettings = true; drawer = false"
+          )
+            v-icon(start icon="mdi-cog")
+            | {{ $t('nav.settings') }}
+
+          v-btn.justify-start.px-4(
+            variant="text"
+            block
+            color="grey-lighten-1"
+            :loading="syncing"
+            @click="manualSync"
+          )
+            v-icon(start icon="mdi-sync")
+            | {{ $t('nav.sync') }}
+
+          v-btn.justify-start.px-4.text-red-lighten-2(
+            variant="text"
+            block
+            @click="handleLogout"
+          )
+            v-icon(start icon="mdi-logout")
+            | {{ $t('nav.logout') }}
+
+    v-app-bar.px-2.app-bar-blur(
+      flat
+      color="rgba(30, 30, 36, 0.8)"
+      border="b"
+    )
+      v-app-bar-title.font-weight-bold.text-h6(style="min-width: fit-content;")
+        .d-flex.align-center.cursor-pointer.logo-hover(@click="$router.push('/')")
+          img(:src="logo" height="32" width="32" alt="Zen Kanji Logo")
+          span.ml-3.tracking-tight Zen Kanji
+
+      v-spacer
+
+      template(v-if="store.token")
+        .d-none.d-md-flex.align-center
+          v-btn.mx-1(
+            to="/"
+            :active="false"
+            variant="text"
+            :color="$route.path === '/' ? '#00cec9' : 'grey'"
+          ) {{ $t('nav.dashboard') }}
+
+          v-btn.mx-1(
+            to="/collection"
+            :active="false"
+            variant="text"
+            :color="$route.path === '/collection' ? '#00cec9' : 'grey'"
+          ) {{ $t('nav.collection') }}
+
+          v-divider.mx-2.my-auto(vertical length="20" color="grey-darken-2")
+
+          v-tooltip(:text="$t('nav.settings')" location="bottom")
+            template(v-slot:activator="{ props }")
+              v-btn(
+                v-bind="props"
+                icon="mdi-cog"
+                variant="text"
+                color="grey-lighten-1"
+                @click="showSettings = true"
+              )
+
+          v-tooltip(:text="$t('nav.sync')" location="bottom")
+            template(v-slot:activator="{ props }")
+              v-btn(
+                v-bind="props"
+                icon="mdi-sync"
+                variant="text"
+                :loading="syncing"
+                color="grey-lighten-1"
+                @click="manualSync"
+              )
+
+          v-tooltip(:text="$t('nav.logout')" location="bottom")
+            template(v-slot:activator="{ props }")
+              v-btn(
+                v-bind="props"
+                icon="mdi-logout"
+                variant="text"
+                color="grey-darken-1"
+                @click="handleLogout"
+              )
+
+        .d-flex.d-md-none
+          v-btn(
+            icon="mdi-menu"
+            variant="text"
+            color="grey-lighten-1"
+            @click="drawer = !drawer"
+          )
+
+    v-main
+      .fill-height.d-flex.align-center.justify-center.px-4(v-if="!store.token")
+        v-card.pa-6.rounded-lg.elevation-10.text-center.border-subtle(
+          color="#1e1e24"
+          width="100%"
+          max-width="400"
+        )
+          img.mb-4(:src="logo" height="64" width="64")
+
+          h1.text-h5.font-weight-bold.mb-2 {{ $t('hero.welcome') }}
+          p.text-grey-lighten-1.text-body-2.mb-6 {{ $t('login.instruction') }}
+
+          v-text-field.mb-2(
+            v-model="inputKey"
+            :placeholder="$t('login.placeholder')"
+            variant="solo-filled"
+            bg-color="#2f3542"
+            color="white"
+            hide-details
+            density="comfortable"
+            @keyup.enter="handleLogin"
+          )
+
+          v-alert.mb-4.text-left.text-caption(
+            v-if="errorMsg"
+            type="error"
+            density="compact"
+            variant="tonal"
+          ) {{ errorMsg }}
+
+          v-btn.text-black.font-weight-bold.mt-4(
+            block
+            color="#00cec9"
+            height="44"
+            :loading="loggingIn"
+            @click="handleLogin"
+          ) {{ $t('login.button') }}
+
+      router-view(v-else)
+
+    v-dialog(v-model="showSettings" max-width="340")
+      v-card.rounded-xl.pa-4.border-subtle(color="#1e1e24")
+        v-card-title.text-center.font-weight-bold {{ $t('settings.title') }}
+
+        v-card-text.pt-4
+          .text-caption.text-grey.mb-2 {{ $t('settings.batchSize') }}
+          v-slider(
+            v-model="tempBatchSize"
+            :min="5"
+            :max="100"
+            :step="5"
+            thumb-label
+            color="#00cec9"
+            track-color="grey-darken-3"
+          )
+          .text-center.text-h5.font-weight-bold.text-teal-accent-3.mb-6
+            | {{ tempBatchSize }} {{ $t('settings.items') }}
+
+          .text-caption.text-grey.mb-2 Drawing Tolerance
+          v-slider(
+            v-model="tempDrawingAccuracy"
+            :min="5"
+            :max="20"
+            :step="1"
+            thumb-label
+            color="#00cec9"
+            track-color="grey-darken-3"
+          )
+          .d-flex.justify-space-between.text-caption.text-grey-lighten-1.mb-6.px-1
+            span Strict (5)
+            span.font-weight-bold.text-body-1(color="#00cec9") {{ tempDrawingAccuracy }}
+            span Loose (20)
+
+          .text-caption.text-grey.mb-2 {{ $t('settings.language') }}
+          v-btn-toggle.d-flex.w-100.border-subtle(
+            v-model="$i18n.locale"
+            mandatory
+            rounded="lg"
+            color="#00cec9"
+          )
+            v-btn.flex-grow-1(value="en") EN
+            v-btn.flex-grow-1(value="de") DE
+            v-btn.flex-grow-1(value="ja") JA
+
+        v-card-actions.mt-2
+          v-btn.text-white(
+            block
+            color="#2f3542"
+            @click="saveSettings"
+          ) {{ $t('settings.save') }}
+
+    v-dialog(v-model="showLogoutDialog" max-width="320")
+      v-card.rounded-xl.pa-4.border-subtle(color="#1e1e24")
+        .d-flex.flex-column.align-center.text-center.pt-2
+          v-avatar.mb-3(color="red-darken-4" size="48")
+            v-icon(icon="mdi-logout" size="24" color="red-lighten-1")
+
+          h3.text-h6.font-weight-bold.mb-2 {{ $t('nav.logout') }}?
+
+          p.text-body-2.text-grey-lighten-1.px-2.mb-4
+            | {{ $t('alerts.logoutConfirm') }}
+
+        v-card-actions.d-flex.gap-2.pa-0.mt-2
+          v-btn.flex-grow-1.text-capitalize(
+            variant="tonal"
+            color="grey"
+            height="40"
+            @click="showLogoutDialog = false"
+          ) {{ $t('common.cancel') }}
+
+          v-btn.flex-grow-1.text-capitalize(
+            color="red-accent-2"
+            variant="flat"
+            height="40"
+            @click="confirmLogout"
+          ) {{ $t('nav.logout') }}
+
+    v-snackbar(v-model="snackbar.show" :color="snackbar.color" timeout="3000")
+      | {{ snackbar.text }}
+      template(v-slot:actions)
+        v-btn(variant="text" @click="snackbar.show = false") {{ $t('common.close') }}
+</template>
+
+<script setup>
+import { ref, watch, onMounted } from 'vue';
+import { useAppStore } from '@/stores/appStore';
+import { useI18n } from 'vue-i18n';
+import logo from '@/assets/icon.svg';
+
+const drawer = ref(false);
+const { locale, t } = useI18n();
+const store = useAppStore();
+
+const inputKey = ref('');
+const loggingIn = ref(false);
+const syncing = ref(false);
+const errorMsg = ref('');
+const showSettings = ref(false);
+const showLogoutDialog = ref(false);
+const snackbar = ref({ show: false, text: '', color: 'success' });
+
+const tempBatchSize = ref(store.batchSize);
+const tempDrawingAccuracy = ref(store.drawingAccuracy);
+
+onMounted(() => {
+	if (store.token) {
+		store.fetchStats();
+	}
+});
+
+watch(showSettings, (isOpen) => {
+	if (isOpen) {
+		tempBatchSize.value = store.batchSize;
+		tempDrawingAccuracy.value = store.drawingAccuracy;
+	}
+});
+
+async function handleLogin() {
+	if (!inputKey.value) return;
+	loggingIn.value = true;
+	errorMsg.value = '';
+
+	try {
+		const result = await store.login(inputKey.value.trim());
+		if (result.user && !result.user.lastSync) {
+			manualSync();
+		}
+	} catch (e) {
+		console.error(e);
+		errorMsg.value = e.message || t('login.failed');
+	} finally {
+		loggingIn.value = false;
+	}
+}
+
+async function manualSync() {
+	syncing.value = true;
+	try {
+		const result = await store.sync();
+		snackbar.value = { show: true, text: t('alerts.syncSuccess', { count: result.count }), color: 'success' };
+		await store.fetchQueue();
+		await store.fetchStats();
+		await store.fetchCollection();
+	} catch (e) {
+		console.error(e);
+		snackbar.value = { show: true, text: t('alerts.syncFailed'), color: 'error' };
+	} finally {
+		syncing.value = false;
+	}
+}
+
+function saveSettings() {
+	store.saveSettings({
+		batchSize: tempBatchSize.value,
+		drawingAccuracy: tempDrawingAccuracy.value
+	});
+
+	localStorage.setItem('zen_locale', locale.value);
+
+	showSettings.value = false;
+	store.fetchQueue();
+}
+
+function handleLogout() {
+	showLogoutDialog.value = true;
+	drawer.value = false;
+}
+function confirmLogout() {
+	store.logout();
+	inputKey.value = '';
+	showLogoutDialog.value = false;
+}
+</script>
+
+<style lang="scss" src="@/styles/pages/_app.scss"></style>
--- a/client/src/assets/android-chrome-192x192.png
+++ b/client/src/assets/android-chrome-192x192.png
--- a/client/src/assets/android-chrome-512x512.png
+++ b/client/src/assets/android-chrome-512x512.png
--- a/client/src/assets/apple-touch-icon.png
+++ b/client/src/assets/apple-touch-icon.png
--- a/client/src/assets/favicon-16x16.png
+++ b/client/src/assets/favicon-16x16.png
--- a/client/src/assets/favicon-32x32.png
+++ b/client/src/assets/favicon-32x32.png
--- a/client/src/assets/favicon.ico
+++ b/client/src/assets/favicon.ico
--- a/client/src/assets/icon.svg
+++ b/client/src/assets/icon.svg
--- a/client/src/components/dashboard/WidgetAccuracy.vue
+++ b/client/src/components/dashboard/WidgetAccuracy.vue
@@ -0,0 +1,38 @@
+<template lang="pug">
+  v-card.pa-4.rounded-xl.border-subtle.d-flex.align-center.justify-space-between(color="#1e1e24")
+    div
+      .text-subtitle-2.text-grey {{ $t('stats.accuracy') }}
+      .text-h3.font-weight-bold.text-white {{ accuracyPercent }}%
+      .text-caption.text-grey
+        | {{ accuracy?.correct || 0 }} {{ $t('stats.correct') }} / {{ accuracy?.total || 0 }} {{ $t('stats.total') }}
+
+    v-progress-circular(
+      :model-value="accuracyPercent"
+      color="#00cec9"
+      size="100"
+      width="10"
+      bg-color="grey-darken-3"
+    )
+      v-icon(color="#00cec9" size="large") mdi-bullseye-arrow
+</template>
+
+<script setup>
+import { computed } from 'vue';
+
+const props = defineProps({
+	accuracy: {
+		type: Object,
+		default: () => ({
+			correct: 0,
+			total: 0
+		})
+	}
+});
+
+const accuracyPercent = computed(() => {
+	if (!props.accuracy || !props.accuracy.total) return 100;
+	return Math.round((props.accuracy.correct / props.accuracy.total) * 100);
+});
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped></style>
--- a/client/src/components/dashboard/WidgetDistribution.vue
+++ b/client/src/components/dashboard/WidgetDistribution.vue
@@ -0,0 +1,73 @@
+<template lang="pug">
+  v-card.pa-5.rounded-xl.border-subtle.d-flex.flex-column.flex-grow-1(color="#1e1e24")
+    .d-flex.align-center.justify-space-between.mb-4
+      .text-subtitle-1.font-weight-bold.d-flex.align-center
+        v-icon(color="#ffeaa7" start size="small") mdi-chart-bar
+        | {{ $t('stats.srsDistribution') }}
+      v-chip.font-weight-bold(
+        size="x-small"
+        color="white"
+        variant="tonal"
+      ) {{ totalItems }}
+
+    .srs-chart-container.d-flex.justify-space-between.align-end.px-2.gap-2.flex-grow-1
+      .d-flex.flex-column.align-center.flex-grow-1.srs-column(
+        v-for="lvl in 10"
+        :key="lvl"
+      )
+        .text-caption.font-weight-bold.mb-2.transition-text(
+          :class="getCount(lvl) > 0 ? 'text-white' : 'text-grey-darken-3'"
+        ) {{ getCount(lvl) }}
+
+        .srs-track
+          .srs-fill(:style="{\
+            height: getBarHeight(getCount(lvl)) + '%',\
+            background: getSRSColor(lvl),\
+            boxShadow: getCount(lvl) > 0 ? `0 0 20px ${getSRSColor(lvl)}30` : 'none'\
+          }")
+
+        .text-caption.text-grey-darken-1.font-weight-bold.mt-3(
+          style="font-size: 10px !important;"
+        ) {{ toRoman(lvl) }}
+</template>
+
+<script setup>
+import { computed } from 'vue';
+
+const props = defineProps({
+	distribution: {
+		type: Object,
+		default: () => ({})
+	}
+});
+
+const totalItems = computed(() => Object.values(props.distribution || {}).reduce((a, b) => a + b, 0));
+
+const getCount = (lvl) => props.distribution?.[lvl] || 0;
+
+const getBarHeight = (count) => {
+	const max = Math.max(...Object.values(props.distribution || {}), 1);
+	if (count > 0 && (count / max) * 100 < 4) return 4;
+	return (count / max) * 100;
+};
+
+const getSRSColor = (lvl) => {
+	const colors = {
+		1: '#ff7675', 2: '#fdcb6e', 3: '#55efc4',
+		4: '#0984e3', 5: '#a29bfe', 6: '#6c5ce7',
+		7: '#00cec9', 8: '#fd79a8', 9: '#e84393',
+		10: '#ffd700'
+	};
+	return colors[lvl] || '#444';
+};
+
+const toRoman = (num) => {
+	const lookup = {
+		1: 'I', 2: 'II', 3: 'III', 4: 'IV', 5: 'V',
+		6: 'VI', 7: 'VII', 8: 'VIII', 9: 'IX', 10: 'X'
+	};
+	return lookup[num] || num;
+};
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped></style>
--- a/client/src/components/dashboard/WidgetForecast.vue
+++ b/client/src/components/dashboard/WidgetForecast.vue
@@ -0,0 +1,41 @@
+<template lang="pug">
+  v-card.pa-4.rounded-xl.border-subtle.d-flex.flex-column.flex-grow-1(color="#1e1e24")
+    .text-subtitle-1.font-weight-bold.mb-3.d-flex.align-center
+      v-icon(color="#ffeaa7" start) mdi-clock-outline
+      | {{ $t('stats.next24') }}
+
+    .forecast-list.flex-grow-1(v-if="hasUpcoming")
+      div(v-for="(count, hour) in forecast" :key="hour")
+        .d-flex.justify-space-between.align-center.mb-2.py-2.border-b-subtle(v-if="count > 0")
+          span.text-body-2.text-grey-lighten-1
+            | {{ hour === 0 ? $t('stats.availableNow') : $t('stats.inHours', { n: hour }, hour) }}
+          v-chip.font-weight-bold(
+            size="small"
+            color="#2f3542"
+            style="color: #00cec9 !important;"
+          ) {{ count }}
+
+    .fill-height.d-flex.align-center.justify-center.text-grey.text-center.pa-4(v-else)
+      | {{ $t('stats.noIncoming') }}
+</template>
+
+<script setup>
+import { computed } from 'vue';
+
+const props = defineProps({
+	forecast: {
+		type: Object,
+		default: () => ({})
+	}
+});
+
+const hasUpcoming = computed(() => {
+	return props.forecast && props.forecast.some(c => c > 0);
+});
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped>
+.border-b-subtle {
+	border-bottom: 1px solid rgb(255 255 255 / 5%);
+}
+</style>
--- a/client/src/components/dashboard/WidgetGhosts.vue
+++ b/client/src/components/dashboard/WidgetGhosts.vue
@@ -0,0 +1,32 @@
+<template lang="pug">
+  v-card.pa-4.rounded-xl.border-subtle(color="#1e1e24")
+    .d-flex.justify-space-between.align-center.mb-3
+      .d-flex.align-center
+        v-icon(color="#ff7675" start size="small") mdi-ghost
+        div
+          .text-subtitle-2.text-white {{ $t('stats.ghostTitle') }}
+          .text-caption.text-grey {{ $t('stats.ghostSubtitle') }}
+
+    .d-flex.justify-space-between.gap-2(v-if="ghosts && ghosts.length > 0")
+      .ghost-card.flex-grow-1(v-for="ghost in ghosts" :key="ghost._id")
+        .text-h6.font-weight-bold.text-white.mb-1 {{ ghost.char }}
+        v-chip.font-weight-bold.text-black.w-100.justify-center(
+          size="x-small"
+          color="red-accent-2"
+          variant="flat"
+        ) {{ ghost.accuracy }}%
+
+    .text-center.py-2.text-caption.text-grey(v-else)
+      | {{ $t('stats.noGhosts') }}
+</template>
+
+<script setup>
+const props = defineProps({
+	ghosts: {
+		type: Array,
+		default: () => []
+	}
+});
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped></style>
--- a/client/src/components/dashboard/WidgetGuruMastery.vue
+++ b/client/src/components/dashboard/WidgetGuruMastery.vue
@@ -0,0 +1,45 @@
+<template lang="pug">
+  v-card.widget-card.pa-5.rounded-xl.d-flex.flex-column.justify-center(color="#1e1e24" flat)
+    .d-flex.justify-space-between.align-center.mb-2
+      .d-flex.align-center
+        v-icon(color="secondary" start size="small") mdi-trophy-outline
+        span.text-subtitle-2.font-weight-bold {{ $t('stats.mastery') }}
+      .text-subtitle-2.text-white.font-weight-bold {{ masteryPercent }}%
+
+    v-progress-linear(
+      :model-value="masteryPercent"
+      color="primary"
+      height="8"
+      rounded
+      bg-color="grey-darken-3"
+      striped
+    )
+
+    .text-caption.text-medium-emphasis.mt-2.text-right
+      | {{ masteredCount }} / {{ totalItems }} {{ $t('stats.items') }}
+</template>
+
+<script setup>
+import { computed } from 'vue';
+
+const props = defineProps({
+	distribution: {
+		type: Object,
+		default: () => ({})
+	}
+});
+
+const totalItems = computed(() => Object.values(props.distribution || {}).reduce((a, b) => a + b, 0));
+
+const masteredCount = computed(() => {
+	const dist = props.distribution || {};
+	return (dist[6] || 0);
+});
+
+const masteryPercent = computed(() => {
+	if (totalItems.value === 0) return 0;
+	return Math.round((masteredCount.value / totalItems.value) * 100);
+});
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped></style>
--- a/client/src/components/dashboard/WidgetHeatmap.vue
+++ b/client/src/components/dashboard/WidgetHeatmap.vue
@@ -0,0 +1,89 @@
+<template lang="pug">
+  v-card.widget-card.pa-4.rounded-xl(color="#1e1e24" flat)
+    .d-flex.flex-wrap.justify-space-between.align-center.mb-4.gap-2
+      .text-subtitle-1.font-weight-bold.d-flex.align-center
+        v-icon(color="secondary" start) mdi-calendar-check
+        | {{ $t('stats.consistency') }}
+
+      .legend-container
+        span.text-caption.text-medium-emphasis.mr-1 {{ $t('stats.less') }}
+        .legend-box.level-0
+        .legend-box.level-1
+        .legend-box.level-2
+        .legend-box.level-3
+        .legend-box.level-4
+        span.text-caption.text-medium-emphasis.ml-1 {{ $t('stats.more') }}
+
+    .heatmap-container
+      .heatmap-year
+        .heatmap-week(v-for="(week, wIdx) in weeks" :key="wIdx")
+          .heatmap-day-wrapper(v-for="(day, dIdx) in week" :key="dIdx")
+            v-tooltip(location="top" open-delay="100")
+              template(v-slot:activator="{ props }")
+                .heatmap-cell(
+                  v-bind="props"
+                  :class="[\
+                    isToday(day.date) ? 'today-cell' : '',\
+                    getHeatmapClass(day.count)\
+                  ]"
+                )
+              .text-center
+                .font-weight-bold {{ formatDate(day.date) }}
+                div {{ $t('stats.reviewsCount', { count: day.count }) }}
+</template>
+
+<script setup>
+import { computed } from 'vue';
+
+import { useI18n } from 'vue-i18n';
+const { locale } = useI18n();
+
+const props = defineProps({
+	heatmapData: {
+		type: Object,
+		default: () => ({})
+	}
+});
+
+const weeks = computed(() => {
+	const data = props.heatmapData || {};
+	const w = [];
+	const today = new Date();
+
+	const startDate = new Date(today);
+	startDate.setDate(today.getDate() - (52 * 7));
+	const dayOfWeek = startDate.getDay();
+	startDate.setDate(startDate.getDate() - dayOfWeek);
+
+	let currentWeek = [];
+	for (let i = 0; i < 371; i++) {
+		const d = new Date(startDate);
+		d.setDate(startDate.getDate() + i);
+		const dateStr = d.toISOString().split('T')[0];
+
+		currentWeek.push({
+			date: dateStr,
+			count: data[dateStr] || 0
+		});
+
+		if (currentWeek.length === 7) {
+			w.push(currentWeek);
+			currentWeek = [];
+		}
+	}
+	return w;
+});
+
+const getHeatmapClass = (count) => {
+	if (count === 0) return 'level-0';
+	if (count <= 5) return 'level-1';
+	if (count <= 10) return 'level-2';
+	if (count <= 20) return 'level-3';
+	return 'level-4';
+};
+
+const formatDate = (dateStr) => new Date(dateStr).toLocaleDateString(locale.value, { month: 'short', day: 'numeric' });
+const isToday = (dateStr) => dateStr === new Date().toISOString().split('T')[0];
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped></style>
--- a/client/src/components/dashboard/WidgetStreak.vue
+++ b/client/src/components/dashboard/WidgetStreak.vue
@@ -0,0 +1,59 @@
+<template lang="pug">
+  v-card.pa-4.rounded-xl.border-subtle(color="#1e1e24")
+    .d-flex.justify-space-between.align-start.mb-2
+      div
+        .text-subtitle-2.text-grey {{ $t('stats.streakTitle') }}
+        .d-flex.align-center
+          .text-h3.font-weight-bold.text-white.mr-2 {{ streak?.current || 0 }}
+          .text-h6.text-grey {{ $t('stats.days') }}
+
+      .text-center
+        v-tooltip(
+          location="start"
+          :text="streak?.shield?.ready ? $t('stats.shieldActive') : $t('stats.shieldCooldown', { n: streak?.shield?.cooldown })"
+        )
+          template(v-slot:activator="{ props }")
+            v-avatar(
+              v-bind="props"
+              size="48"
+              :color="streak?.shield?.ready ? 'rgba(0, 206, 201, 0.1)' : 'rgba(255, 255, 255, 0.05)'"
+              style="border: 1px solid;"
+              :style="{ borderColor: streak?.shield?.ready ? '#00cec9' : '#555' }"
+            )
+              v-icon(:color="streak?.shield?.ready ? '#00cec9' : 'grey'")
+                | {{ streak?.shield?.ready ? 'mdi-shield-check' : 'mdi-shield-off-outline' }}
+
+    .d-flex.justify-space-between.align-center.mt-2.px-1
+      .d-flex.flex-column.align-center(
+        v-for="(day, idx) in (streak?.history || [])"
+        :key="idx"
+      )
+        .streak-dot.mb-1(:class="{ 'active': day.active }")
+          v-icon(v-if="day.active" size="12" color="black") mdi-check
+        .text-grey.text-uppercase(style="font-size: 10px;")
+          | {{ getDayLabel(day.date) }}
+</template>
+
+<script setup>
+import { useI18n } from 'vue-i18n';
+
+const props = defineProps({
+	streak: {
+		type: Object,
+		required: true,
+		default: () => ({
+			current: 0,
+			history: [],
+			shield: { ready: false, cooldown: 0 }
+		})
+	}
+});
+const { locale } = useI18n();
+
+const getDayLabel = (dateStr) => {
+	if (!dateStr) return '';
+	return new Date(dateStr).toLocaleDateString(locale.value, { weekday: 'short' });
+};
+</script>
+
+<style lang="scss" src="@/styles/components/_widgets.scss" scoped></style>
--- a/client/src/components/dashboard/WidgetWelcome.vue
+++ b/client/src/components/dashboard/WidgetWelcome.vue
@@ -0,0 +1,76 @@
+<template lang="pug">
+  .grid-area-full.text-center.mb-4
+    .text-h2.font-weight-bold.mb-2 {{ $t('hero.welcome') }}
+    .text-h5.text-grey.mb-8 {{ $t('hero.subtitle') }}
+
+    .d-flex.justify-center.align-center.flex-column
+      v-btn.text-h5.font-weight-bold.text-black.glow-btn(
+        @click="$emit('start', 'shuffled')"
+        height="80"
+        width="280"
+        rounded="xl"
+        color="#00cec9"
+        :disabled="queueLength === 0"
+      )
+        v-icon(size="32" start) mdi-brush
+        | {{ queueLength > 0 ? $t('hero.start') : $t('hero.noReviews') }}
+
+        v-chip.ml-3.font-weight-bold(
+          v-if="queueLength > 0"
+          color="#1e1e24"
+          variant="flat"
+          size="default"
+          style="color: white !important;"
+        ) {{ queueLength }}
+
+      v-fade-transition
+        v-btn.mt-4.text-caption.font-weight-bold(
+          v-if="hasLowerLevels"
+          @click="$emit('start', 'priority')"
+          variant="plain"
+          color="grey-lighten-1"
+          prepend-icon="mdi-sort-ascending"
+          :ripple="false"
+        ) {{ $t('hero.prioritize', { count: lowerLevelCount }) }}
+
+      .text-caption.text-grey.mt-2(v-if="queueLength === 0")
+        | {{ $t('hero.nextIn') }} {{ nextReviewTime }}
+</template>
+
+<script setup>
+import { computed } from 'vue';
+import { useI18n } from 'vue-i18n';
+
+const props = defineProps({
+	queueLength: {
+		type: Number,
+		required: true
+	},
+	hasLowerLevels: {
+		type: Boolean,
+		default: false
+	},
+	lowerLevelCount: {
+		type: Number,
+		default: 0
+	},
+	forecast: {
+		type: Object,
+		default: () => ({})
+	}
+});
+defineEmits(['start']);
+
+const { t } = useI18n();
+
+const nextReviewTime = computed(() => {
+	if (!props.forecast) return "a while";
+
+	const idx = props.forecast.findIndex(c => c > 0);
+
+	if (idx === -1) return "a while";
+	return idx === 0 ? t('hero.now') : t('stats.inHours', { n: idx }, idx);
+});
+</script>
+
+<style lang="scss" src="@/styles/components/_buttons.scss" scoped></style>
--- a/client/src/components/kanji/KanjiCanvas.vue
+++ b/client/src/components/kanji/KanjiCanvas.vue
@@ -0,0 +1,247 @@
+<template lang="pug">
+  .canvas-container
+    .loading-text(v-if="loading") {{ $t('review.loading') }}
+
+    .canvas-wrapper(ref="wrapper")
+      canvas(
+        ref="bgCanvas"
+        :width="CANVAS_SIZE"
+        :height="CANVAS_SIZE"
+      )
+      canvas(
+        ref="snapCanvas"
+        :width="CANVAS_SIZE"
+        :height="CANVAS_SIZE"
+      )
+      canvas(
+        ref="drawCanvas"
+        :width="CANVAS_SIZE"
+        :height="CANVAS_SIZE"
+        @mousedown="startDraw"
+        @mousemove="draw"
+        @mouseup="endDraw"
+        @mouseleave="endDraw"
+        @touchstart.prevent="startDraw"
+        @touchmove.prevent="draw"
+        @touchend.prevent="endDraw"
+      )
+</template>
+
+<script setup>
+import { ref, onMounted, watch } from 'vue';
+import { useAppStore } from '@/stores/appStore';
+
+const props = defineProps({
+	char: {
+		type: String,
+		required: true
+	}
+});
+const emit = defineEmits(['complete', 'mistake']);
+const store = useAppStore();
+
+const KANJI_SIZE = 109;
+const CANVAS_SIZE = 300;
+const SCALE = CANVAS_SIZE / KANJI_SIZE;
+
+const wrapper = ref(null);
+const bgCanvas = ref(null);
+const snapCanvas = ref(null);
+const drawCanvas = ref(null);
+let ctxBg, ctxSnap, ctxDraw;
+
+const kanjiPaths = ref([]);
+const currentStrokeIndex = ref(0);
+const failureCount = ref(0);
+const loading = ref(false);
+let isDrawing = false;
+let userPath = [];
+
+onMounted(() => {
+	initContexts();
+	if (props.char) loadKanji(props.char);
+});
+
+watch(() => props.char, (newChar) => {
+	if (newChar) loadKanji(newChar);
+});
+
+function initContexts() {
+	ctxBg = bgCanvas.value.getContext('2d');
+	ctxSnap = snapCanvas.value.getContext('2d');
+	ctxDraw = drawCanvas.value.getContext('2d');
+
+	[ctxBg, ctxSnap, ctxDraw].forEach(ctx => {
+		ctx.setTransform(1, 0, 0, 1, 0, 0);
+		ctx.scale(SCALE, SCALE);
+		ctx.lineCap = "round";
+		ctx.lineJoin = "round";
+	});
+}
+
+async function loadKanji(char) {
+	reset();
+	loading.value = true;
+	const hex = char.charCodeAt(0).toString(16).padStart(5, '0');
+
+	try {
+		const res = await fetch(`https://raw.githubusercontent.com/KanjiVG/kanjivg/master/kanji/${hex}.svg`);
+		const txt = await res.text();
+		const parser = new DOMParser();
+		const doc = parser.parseFromString(txt, "image/svg+xml");
+		kanjiPaths.value = Array.from(doc.getElementsByTagName("path")).map(p => p.getAttribute("d"));
+
+		drawGuide();
+	} catch (e) {
+		console.error("Failed to load KanjiVG data", e);
+	} finally {
+		loading.value = false;
+	}
+}
+
+function reset() {
+	currentStrokeIndex.value = 0;
+	failureCount.value = 0;
+	kanjiPaths.value = [];
+
+	[ctxBg, ctxSnap, ctxDraw].forEach(ctx => {
+		ctx.clearRect(0, 0, KANJI_SIZE, KANJI_SIZE);
+	});
+}
+
+function getCoords(e) {
+	const rect = drawCanvas.value.getBoundingClientRect();
+	const cx = e.touches ? e.touches[0].clientX : e.clientX;
+	const cy = e.touches ? e.touches[0].clientY : e.clientY;
+
+	return {
+		x: (cx - rect.left) / SCALE,
+		y: (cy - rect.top) / SCALE
+	};
+}
+
+function startDraw(e) {
+	if (currentStrokeIndex.value >= kanjiPaths.value.length) return;
+	isDrawing = true;
+	userPath = [];
+
+	const p = getCoords(e);
+	userPath.push(p);
+
+	ctxDraw.beginPath();
+	ctxDraw.moveTo(p.x, p.y);
+	ctxDraw.strokeStyle = '#ff7675';
+	ctxDraw.lineWidth = 4;
+}
+
+function draw(e) {
+	if (!isDrawing) return;
+	const p = getCoords(e);
+	userPath.push(p);
+	ctxDraw.lineTo(p.x, p.y);
+	ctxDraw.stroke();
+}
+
+function endDraw() {
+	if (!isDrawing) return;
+	isDrawing = false;
+
+	const targetD = kanjiPaths.value[currentStrokeIndex.value];
+
+	if (checkMatch(userPath, targetD)) {
+		ctxSnap.strokeStyle = '#00cec9';
+		ctxSnap.lineWidth = 4;
+		ctxSnap.stroke(new Path2D(targetD));
+
+		currentStrokeIndex.value++;
+		failureCount.value = 0;
+		ctxDraw.clearRect(0, 0, KANJI_SIZE, KANJI_SIZE);
+
+		if (currentStrokeIndex.value >= kanjiPaths.value.length) {
+			emit('complete');
+		} else {
+			drawGuide();
+		}
+	} else {
+		failureCount.value++;
+		ctxDraw.clearRect(0, 0, KANJI_SIZE, KANJI_SIZE);
+
+		if (failureCount.value >= 3) {
+			drawGuide(true);
+			emit('mistake', true);
+		} else {
+			emit('mistake', false);
+		}
+	}
+}
+
+function checkMatch(userPts, targetD) {
+	if (userPts.length < 5) return false;
+
+	const tempPath = document.createElementNS("http://www.w3.org/2000/svg", "path");
+	tempPath.setAttribute("d", targetD);
+	const len = tempPath.getTotalLength();
+	const targetEnd = tempPath.getPointAtLength(len);
+	const userEnd = userPts[userPts.length - 1];
+
+	const threshold = store.drawingAccuracy || 10;
+
+	const dist = (p1, p2) => Math.hypot(p1.x - p2.x, p1.y - p2.y);
+	if (dist(userEnd, targetEnd) > threshold * 3.0) return false;
+
+	let totalError = 0;
+	const samples = 10;
+	for (let i = 0; i <= samples; i++) {
+		const pt = tempPath.getPointAtLength((i / samples) * len);
+		let min = Infinity;
+		for (let p of userPts) min = Math.min(min, dist(pt, p));
+		totalError += min;
+	}
+	return (totalError / (samples + 1)) < threshold;
+}
+
+function drawGuide(showHint = false) {
+	ctxBg.clearRect(0, 0, KANJI_SIZE, KANJI_SIZE);
+
+	if (!showHint) return;
+
+	const d = kanjiPaths.value[currentStrokeIndex.value];
+	if (!d) return;
+
+	ctxBg.strokeStyle = '#57606f';
+	ctxBg.lineWidth = 3;
+	ctxBg.setLineDash([5, 5]);
+	ctxBg.stroke(new Path2D(d));
+	ctxBg.setLineDash([]);
+
+	const tempPath = document.createElementNS("http://www.w3.org/2000/svg", "path");
+	tempPath.setAttribute("d", d);
+	const len = tempPath.getTotalLength();
+	const mid = tempPath.getPointAtLength(len / 2);
+	const prev = tempPath.getPointAtLength(Math.max(0, (len / 2) - 1));
+	const angle = Math.atan2(mid.y - prev.y, mid.x - prev.x);
+
+	ctxBg.save();
+	ctxBg.translate(mid.x, mid.y);
+	ctxBg.rotate(angle);
+
+	ctxBg.strokeStyle = 'rgba(255, 234, 167, 0.7)';
+	ctxBg.lineWidth = 2;
+	ctxBg.lineCap = 'round';
+	ctxBg.lineJoin = 'round';
+
+	ctxBg.beginPath();
+	ctxBg.moveTo(-7, 0);
+	ctxBg.lineTo(2, 0);
+	ctxBg.moveTo(-1, -3);
+	ctxBg.lineTo(2, 0);
+	ctxBg.lineTo(-1, 3);
+	ctxBg.stroke();
+
+	ctxBg.restore();
+}
+
+defineExpose({ drawGuide });
+</script>
+
+<style lang="scss" src="@/styles/components/_kanji.scss" scoped></style>
--- a/client/src/components/kanji/KanjiSvgViewer.vue
+++ b/client/src/components/kanji/KanjiSvgViewer.vue
@@ -0,0 +1,138 @@
+<template lang="pug">
+  .svg-container(:class="{ loading: loading }")
+    svg.kanji-svg(
+      v-if="!loading"
+      viewBox="0 0 109 109"
+      width="100%"
+      height="100%"
+    )
+      g(v-for="(stroke, i) in strokes" :key="i")
+        path.stroke-path(
+          :d="stroke.d"
+          :class="{\
+            'animating': isPlaying && currentStrokeIdx === i,\
+            'hidden': isPlaying && currentStrokeIdx < i,\
+            'drawn': isPlaying && currentStrokeIdx > i\
+          }"
+          :style="{\
+            '--len': stroke.len,\
+            '--duration': (stroke.len * 0.02) + 's'\
+          }"
+        )
+
+        g(v-show="!isPlaying || currentStrokeIdx > i")
+          circle.stroke-start-circle(
+            v-if="stroke.start"
+            :cx="stroke.start.x"
+            :cy="stroke.start.y"
+            r="3.5"
+          )
+
+          text.stroke-number(
+            v-if="stroke.start"
+            :x="stroke.start.x"
+            :y="stroke.start.y + 0.5"
+          ) {{ i + 1 }}
+
+          path.stroke-arrow-line(
+            v-if="stroke.arrow"
+            d="M -7 0 L 2 0 M -1 -3 L 2 0 L -1 3"
+            :transform="`translate(${stroke.arrow.x}, ${stroke.arrow.y}) rotate(${stroke.arrow.angle})`"
+          )
+
+    .loading-spinner(v-else) {{ $t('review.loading') }}
+
+    button.play-btn(
+      v-if="!loading && !isPlaying"
+      @click="playAnimation"
+    )
+      svg(viewBox="0 0 24 24" fill="currentColor")
+        path(d="M8 5v14l11-7z")
+</template>
+
+<script setup>
+import { ref, watch, onMounted } from 'vue';
+
+const props = defineProps({
+	char: {
+		type: String,
+		required: true
+	}
+});
+const strokes = ref([]);
+const loading = ref(true);
+const isPlaying = ref(false);
+const currentStrokeIdx = ref(-1);
+
+onMounted(() => {
+	if (props.char) loadData(props.char);
+});
+
+watch(() => props.char, (newChar) => {
+	if (newChar) loadData(newChar);
+});
+
+async function loadData(char) {
+	loading.value = true;
+	isPlaying.value = false;
+	strokes.value = [];
+
+	const hex = char.charCodeAt(0).toString(16).padStart(5, '0');
+	try {
+		const res = await fetch(`https://raw.githubusercontent.com/KanjiVG/kanjivg/master/kanji/${hex}.svg`);
+		const txt = await res.text();
+		const parser = new DOMParser();
+		const doc = parser.parseFromString(txt, "image/svg+xml");
+
+		const rawPaths = Array.from(doc.getElementsByTagName("path")).map(p => p.getAttribute("d"));
+
+		strokes.value = rawPaths.map(d => {
+			const data = { d, start: null, arrow: null, len: 0 };
+
+			const tempPath = document.createElementNS("http://www.w3.org/2000/svg", "path");
+			tempPath.setAttribute("d", d);
+			try {
+				data.len = tempPath.getTotalLength();
+			} catch (e) { data.len = 100; }
+
+			const startMatch = d.match(/[Mm]\s*([\d.]+)[,\s]([\d.]+)/);
+			if (startMatch) {
+				data.start = { x: parseFloat(startMatch[1]), y: parseFloat(startMatch[2]) };
+			}
+
+			try {
+				const mid = tempPath.getPointAtLength(data.len / 2);
+				const prev = tempPath.getPointAtLength(Math.max(0, (data.len / 2) - 1));
+				const angle = Math.atan2(mid.y - prev.y, mid.x - prev.x) * (180 / Math.PI);
+				data.arrow = { x: mid.x, y: mid.y, angle };
+			} catch (e) { console.error(e) }
+
+			return data;
+		});
+
+	} catch (e) {
+		console.error("SVG Load Failed", e);
+	} finally {
+		loading.value = false;
+	}
+}
+
+async function playAnimation() {
+	if (isPlaying.value) return;
+	isPlaying.value = true;
+	currentStrokeIdx.value = -1;
+
+	await new Promise(r => setTimeout(r, 200));
+
+	for (let i = 0; i < strokes.value.length; i++) {
+		currentStrokeIdx.value = i;
+		const duration = strokes.value[i].len * 20;
+		await new Promise(r => setTimeout(r, duration + 100));
+	}
+
+	await new Promise(r => setTimeout(r, 500));
+	isPlaying.value = false;
+}
+</script>
+
+<style lang="scss" src="@/styles/components/_kanji.scss" scoped></style>
--- a/client/src/main.js
+++ b/client/src/main.js
@@ -0,0 +1,49 @@
+import { createApp } from 'vue'
+import { createPinia } from 'pinia'
+import { createRouter, createWebHistory } from 'vue-router'
+import i18n from '@/plugins/i18n'
+
+import '@/styles/main.scss'
+
+import 'vuetify/styles'
+import { createVuetify } from 'vuetify'
+import * as components from 'vuetify/components'
+import * as directives from 'vuetify/directives'
+import { aliases, mdi } from 'vuetify/iconsets/mdi'
+import '@mdi/font/css/materialdesignicons.css'
+
+import App from './App.vue'
+import Dashboard from './views/Dashboard.vue'
+import Collection from './views/Collection.vue'
+import Review from './views/Review.vue'
+
+const app = createApp(App)
+const pinia = createPinia()
+
+const router = createRouter({
+	history: createWebHistory(),
+	routes: [
+		{ path: '/', component: Dashboard },
+		{ path: '/dashboard', component: Dashboard },
+		{ path: '/collection', component: Collection },
+		{ path: '/review', component: Review }
+	]
+})
+
+const vuetify = createVuetify({
+	components,
+	directives,
+	theme: {
+		defaultTheme: 'dark',
+		themes: {
+			dark: { colors: { primary: '#00cec9', secondary: '#ffeaa7' } }
+		}
+	},
+	icons: { defaultSet: 'mdi', aliases, sets: { mdi } }
+})
+
+app.use(pinia)
+app.use(router)
+app.use(vuetify)
+app.use(i18n)
+app.mount('#app')
--- a/client/src/plugins/i18n.js
+++ b/client/src/plugins/i18n.js
@@ -0,0 +1,306 @@
+import { createI18n } from 'vue-i18n'
+
+const messages = {
+	en: {
+		common: {
+			close: "Close",
+			cancel: "Cancel"
+		},
+		nav: {
+			dashboard: "Dashboard",
+			review: "Review",
+			collection: "Collection",
+			settings: "Settings",
+			sync: "Sync",
+			logout: "Logout",
+			menu: "Menu"
+		},
+		login: {
+			instruction: "Enter your WaniKani V2 API Key to login",
+			placeholder: "Paste key here...",
+			button: "Login",
+			failed: "Login failed. Is server running?"
+		},
+		alerts: {
+			syncSuccess: "Sync complete! Collection: {count}",
+			syncFailed: "Sync failed.",
+			logoutConfirm: "Are you sure you want to log out? This will end your session.",
+		},
+		hero: {
+			welcome: "Welcome Back",
+			subtitle: "Your mind is ready.",
+			start: "Start Review",
+			noReviews: "No Reviews",
+			nextIn: "Next review in",
+			now: "now",
+			prioritize: "Prioritize Lower Levels ({count})"
+		},
+		stats: {
+			mastery: "Mastery (Guru+)",
+			srsDistribution: "SRS Levels",
+			accuracy: "Global Accuracy",
+			correct: "Correct",
+			total: "Total",
+			next24: "Next 24h",
+			availableNow: "Available Now",
+			inHours: "In {n} hour | In {n} hours",
+			noIncoming: "No reviews incoming for 24 hours.",
+			items: "items",
+			reviewsCount: "{count} reviews",
+
+			consistency: "Study Consistency",
+			less: "Less",
+			more: "More",
+
+			streakTitle: "Study Streak",
+			days: "days",
+			shieldActive: "Zen Shield Active: Protects streak if you miss 1 day.",
+			shieldCooldown: "Regenerating: {n} days left",
+
+			ghostTitle: "Ghost Items",
+			ghostSubtitle: "Lowest Accuracy",
+			noGhosts: "No ghosts found! Keep it up."
+		},
+		settings: {
+			title: "Settings",
+			batchSize: "Review Batch Size",
+			items: "Items",
+			language: "Language",
+			save: "Save & Close"
+		},
+		review: {
+			meaning: "Meaning",
+			level: "Level",
+			draw: "Draw correctly",
+			hint: "Hint Shown",
+			tryAgain: "Try again",
+			correct: "Correct!",
+			next: "NEXT",
+			sessionComplete: "Session Complete!",
+			levelup: "You leveled up your Kanji skills.",
+			back: "Back to Collection",
+			caughtUp: "All Caught Up!",
+			noReviews: "No reviews available right now.",
+			viewCollection: "View Collection",
+			queue: "Session queue:",
+			loading: "Loading Kanji...",
+		},
+		collection: {
+			searchLabel: "Search Kanji, Meaning, or Reading...",
+			placeholder: "e.g. 'water', 'mizu', '水'",
+			loading: "Loading Collection...",
+			noMatches: "No matches found",
+			tryDifferent: "Try searching for a different meaning or reading.",
+			levelHeader: "LEVEL",
+			onyomi: "On'yomi",
+			kunyomi: "Kun'yomi",
+			nanori: "Nanori",
+			close: "Close"
+		}
+	},
+	de: {
+		common: {
+			close: "Schließen",
+			cancel: "Abbrechen"
+		},
+		nav: {
+			dashboard: "Übersicht",
+			review: "Lernen",
+			collection: "Sammlung",
+			settings: "Einstellungen",
+			sync: "Sync",
+			logout: "Abmelden",
+			menu: "Menü"
+		},
+		login: {
+			instruction: "Gib deinen WaniKani V2 API Key ein",
+			placeholder: "Key hier einfügen...",
+			button: "Anmelden",
+			failed: "Login fehlgeschlagen. Läuft der Server?"
+		},
+		alerts: {
+			syncSuccess: "Sync fertig! Sammlung: {count}",
+			syncFailed: "Sync fehlgeschlagen.",
+			logoutConfirm: "Möchtest du dich wirklich abmelden? Deine Sitzung wird beendet.",
+		},
+		hero: {
+			welcome: "Willkommen zurück",
+			subtitle: "Dein Geist ist bereit.",
+			start: "Starten",
+			noReviews: "Alles erledigt",
+			nextIn: "Nächste Review in",
+			now: "jetzt",
+			prioritize: "Niedrige Stufen zuerst ({count})"
+		},
+		stats: {
+			mastery: "Meisterschaft (Guru+)",
+			srsDistribution: "SRS Verteilung",
+			accuracy: "Genauigkeit",
+			correct: "Richtig",
+			total: "Gesamt",
+			next24: "Nächste 24h",
+			availableNow: "Jetzt verfügbar",
+			inHours: "In {n} Stunde | In {n} Stunden",
+			noIncoming: "Keine Reviews in den nächsten 24h.",
+			items: "Einträge",
+			reviewsCount: "{count} Reviews",
+
+			consistency: "Lern-Konstanz",
+			less: "Weniger",
+			more: "Mehr",
+
+			streakTitle: "Lern-Serie",
+			days: "Tage",
+			shieldActive: "Zen-Schild Aktiv: Schützt dich bei einem verpassten Tag.",
+			shieldCooldown: "Regeneriert: noch {n} Tage",
+
+			ghostTitle: "Geister-Items",
+			ghostSubtitle: "Niedrigste Genauigkeit",
+			noGhosts: "Keine Geister gefunden! Weiter so."
+		},
+		settings: {
+			title: "Einstellungen",
+			batchSize: "Anzahl pro Sitzung",
+			items: "Einträge",
+			language: "Sprache",
+			save: "Speichern & Schließen"
+		},
+		review: {
+			meaning: "Bedeutung",
+			level: "Stufe",
+			draw: "Zeichne das Kanji",
+			hint: "Hinweis angezeigt",
+			tryAgain: "Nochmal versuchen",
+			correct: "Richtig!",
+			next: "WEITER",
+			sessionComplete: "Sitzung beendet!",
+			levelup: "Du hast deine Kanji-Skills verbessert.",
+			back: "Zurück zur Sammlung",
+			caughtUp: "Alles erledigt!",
+			noReviews: "Gerade keine Reviews verfügbar.",
+			viewCollection: "Zur Sammlung",
+			queue: "Verbleibend:",
+			loading: "Lade Kanji...",
+		},
+		collection: {
+			searchLabel: "Suche Kanji, Bedeutung oder Lesung...",
+			placeholder: "z.B. 'Wasser', 'mizu'",
+			loading: "Lade Sammlung...",
+			noMatches: "Keine Treffer",
+			tryDifferent: "Versuche einen anderen Suchbegriff.",
+			levelHeader: "STUFE",
+			onyomi: "On'yomi",
+			kunyomi: "Kun'yomi",
+			nanori: "Nanori",
+			close: "Schließen"
+		}
+	},
+	ja: {
+		common: {
+			close: "閉じる",
+			cancel: "キャンセル"
+		},
+		nav: {
+			dashboard: "ダッシュボード",
+			review: "復習",
+			collection: "コレクション",
+			settings: "設定",
+			sync: "同期",
+			logout: "ログアウト",
+			menu: "メニュー"
+		},
+		login: {
+			instruction: "WaniKani V2 APIキーを入力してください",
+			placeholder: "キーを貼り付け...",
+			button: "ログイン",
+			failed: "ログイン失敗。サーバーは起動していますか？"
+		},
+		alerts: {
+			syncSuccess: "同期完了！ コレクション: {count}",
+			syncFailed: "同期に失敗しました。",
+			logoutConfirm: "ログアウトしてもよろしいですか？セッションが終了します。",
+		},
+		hero: {
+			welcome: "お帰りなさい",
+			subtitle: "準備は完了です。",
+			start: "復習開始",
+			noReviews: "レビューなし",
+			nextIn: "次の復習まで",
+			now: "今",
+			prioritize: "低レベルを優先 ({count})"
+		},
+		stats: {
+			mastery: "習得度 (Guru+)",
+			srsDistribution: "SRS分布",
+			accuracy: "正解率",
+			correct: "正解",
+			total: "合計",
+			next24: "今後24時間",
+			availableNow: "今すぐ可能",
+			inHours: "{n}時間後",
+			noIncoming: "24時間以内のレビューはありません。",
+			items: "個",
+			reviewsCount: "{count} レビュー",
+
+			consistency: "学習の一貫性",
+			less: "少",
+			more: "多",
+
+			streakTitle: "連続学習日数",
+			days: "日",
+			shieldActive: "Zenシールド有効: 1日休んでもストリークを守ります。",
+			shieldCooldown: "再チャージ中: 残り{n}日",
+
+			ghostTitle: "苦手なアイテム",
+			ghostSubtitle: "正解率が低い",
+			noGhosts: "苦手なアイテムはありません！"
+		},
+		settings: {
+			title: "設定",
+			batchSize: "1回の復習数",
+			items: "個",
+			language: "言語 (Language)",
+			save: "保存して閉じる"
+		},
+		review: {
+			meaning: "意味",
+			level: "レベル",
+			draw: "正しく描いてください",
+			hint: "ヒント表示",
+			tryAgain: "もう一度",
+			correct: "正解！",
+			next: "次へ",
+			sessionComplete: "セッション完了！",
+			levelup: "漢字力がアップしました。",
+			back: "コレクションに戻る",
+			caughtUp: "完了しました！",
+			noReviews: "現在レビューするものはありません。",
+			viewCollection: "コレクションを見る",
+			queue: "残り:",
+			loading: "漢字を読み込み中...",
+		},
+		collection: {
+			searchLabel: "漢字、意味、読みで検索...",
+			placeholder: "例: '水', 'mizu'",
+			loading: "読み込み中...",
+			noMatches: "見つかりませんでした",
+			tryDifferent: "別のキーワードで検索してください。",
+			levelHeader: "レベル",
+			onyomi: "音読み",
+			kunyomi: "訓読み",
+			nanori: "名乗り",
+			close: "閉じる"
+		}
+	}
+}
+
+const savedLocale = localStorage.getItem('zen_locale') || 'en'
+
+const i18n = createI18n({
+	legacy: false,
+	locale: savedLocale,
+	fallbackLocale: 'en',
+	messages
+})
+
+export default i18n
--- a/client/src/stores/appStore.js
+++ b/client/src/stores/appStore.js
@@ -0,0 +1,136 @@
+import { defineStore } from 'pinia';
+
+const BASE_URL = import.meta.env.VITE_API_URL || 'http://localhost:3000';
+
+export const useAppStore = defineStore('app', {
+	state: () => ({
+		token: localStorage.getItem('zen_token') || '',
+		user: null,
+		queue: [],
+		collection: [],
+		stats: {
+			distribution: {},
+			forecast: [],
+			queueLength: 0,
+			streak: {},
+			accuracy: {},
+			ghosts: []
+		},
+		batchSize: 20,
+		drawingAccuracy: 10,
+		loading: false
+	}),
+
+	actions: {
+		async login(apiKey) {
+			const res = await fetch(`${BASE_URL}/api/auth/login`, {
+				method: 'POST',
+				headers: { 'Content-Type': 'application/json' },
+				body: JSON.stringify({ apiKey })
+			});
+
+			const data = await res.json();
+			if (!res.ok) throw new Error(data.error || 'Login failed');
+
+			this.token = data.token;
+			this.user = data.user;
+
+			if (data.user.settings) {
+				this.batchSize = data.user.settings.batchSize || 20;
+				this.drawingAccuracy = data.user.settings.drawingAccuracy || 10;
+			}
+
+			localStorage.setItem('zen_token', data.token);
+
+			await this.fetchStats();
+			return data;
+		},
+
+		async logout() {
+			try {
+				if (this.token) {
+					await fetch(`${BASE_URL}/api/auth/logout`, {
+						method: 'POST',
+						headers: this.getHeaders()
+					});
+				}
+			} catch (e) {
+				console.error("Logout error:", e);
+			} finally {
+				this.clearData();
+			}
+		},
+
+		clearData() {
+			this.token = '';
+			this.user = null;
+			this.queue = [];
+			this.stats = {};
+			localStorage.removeItem('zen_token');
+		},
+
+		getHeaders() {
+			return {
+				'Authorization': `Bearer ${this.token}`,
+				'Content-Type': 'application/json'
+			};
+		},
+
+		async sync() {
+			const res = await fetch(`${BASE_URL}/api/sync`, {
+				method: 'POST',
+				headers: this.getHeaders(),
+				body: JSON.stringify({})
+			});
+			const data = await res.json();
+			if (!res.ok) throw new Error(data.error);
+			return data;
+		},
+
+		async fetchStats() {
+			if (!this.token) return;
+			const res = await fetch(`${BASE_URL}/api/stats`, { headers: this.getHeaders() });
+			if (res.status === 401) return this.logout();
+			const data = await res.json();
+			this.stats = data;
+			return data;
+		},
+
+		async fetchQueue(sortMode = 'shuffled') {
+			if (!this.token) return;
+			const res = await fetch(`${BASE_URL}/api/queue?limit=${this.batchSize}&sort=${sortMode}`, {
+				headers: this.getHeaders()
+			});
+			if (res.status === 401) return this.logout();
+			this.queue = await res.json();
+		},
+
+		async fetchCollection() {
+			if (!this.token) return;
+			const res = await fetch(`${BASE_URL}/api/collection`, { headers: this.getHeaders() });
+			if (res.status === 401) return this.logout();
+			this.collection = await res.json();
+		},
+
+		async submitReview(subjectId, success) {
+			const res = await fetch(`${BASE_URL}/api/review`, {
+				method: 'POST',
+				headers: this.getHeaders(),
+				body: JSON.stringify({ subjectId, success })
+			});
+			if (res.status === 401) return this.logout();
+			return await res.json();
+		},
+
+		async saveSettings(settings) {
+			if (settings.batchSize) this.batchSize = settings.batchSize;
+			if (settings.drawingAccuracy) this.drawingAccuracy = settings.drawingAccuracy;
+
+			await fetch(`${BASE_URL}/api/settings`, {
+				method: 'POST',
+				headers: this.getHeaders(),
+				body: JSON.stringify(settings)
+			});
+		}
+	}
+});
--- a/client/src/styles/abstracts/_mixins.scss
+++ b/client/src/styles/abstracts/_mixins.scss
@@ -0,0 +1,68 @@
+@use 'sass:color';
+@use 'variables' as *;
+
+@mixin flex-center {
+	display: flex;
+	align-items: center;
+	justify-content: center;
+}
+
+@mixin flex-column($gap: 0) {
+	display: flex;
+	flex-direction: column;
+	gap: $gap;
+}
+
+@mixin grid-responsive($min-width: 960px) {
+	display: grid;
+	grid-template-columns: 1fr;
+
+	@media (min-width: $min-width) {
+		// stylelint-disable-next-line no-invalid-position-declaration
+		grid-template-columns: 1fr 1fr;
+	}
+}
+
+@mixin card-base {
+	background: $color-surface-light;
+	border-radius: $radius-md;
+	border: 1px solid transparent;
+	background-clip: padding-box;
+}
+
+@mixin hover-lift {
+	transition:
+		transform $duration-fast $ease-default,
+		background $duration-fast $ease-default,
+		box-shadow $duration-fast $ease-default;
+	will-change: transform;
+	transform: translateZ(0);
+	backface-visibility: hidden;
+
+	&:hover {
+		transform: translateY(-2px);
+		background: color.adjust($color-surface-light, $lightness: 5%);
+		box-shadow: $shadow-md;
+	}
+}
+
+@mixin scrollbar {
+	scrollbar-width: thin;
+	scrollbar-color: #333 transparent;
+}
+
+@mixin animate-fade-up($duration: 0.4s) {
+	animation: fade-slide-up $duration ease-out backwards;
+
+	@keyframes fade-slide-up {
+		from {
+			opacity: 0;
+			transform: translateY(10px);
+		}
+
+		to {
+			opacity: 1;
+			transform: translateY(0);
+		}
+	}
+}
--- a/client/src/styles/abstracts/_variables.scss
+++ b/client/src/styles/abstracts/_variables.scss
@@ -0,0 +1,5 @@
+@forward 'variables/colors';
+@forward 'variables/typography';
+@forward 'variables/spacing';
+@forward 'variables/layout';
+@forward 'variables/effects';
--- a/client/src/styles/abstracts/variables/_colors.scss
+++ b/client/src/styles/abstracts/variables/_colors.scss
@@ -0,0 +1,18 @@
+$color-primary: hsl(178deg 100% 40%);
+$color-secondary: hsl(46deg 100% 82%);
+$color-bg-dark: hsl(0deg 0% 7%);
+$color-surface: hsl(240deg 9% 13%);
+$color-surface-light: hsl(221deg 17% 22%);
+$color-text-white: hsl(0deg 0% 100%);
+$color-text-grey: hsl(213deg 14% 70%);
+$color-border: hsl(0deg 0% 100% / 8%);
+$color-srs-1: hsl(0deg 100% 73%);
+$color-srs-2: hsl(39deg 98% 71%);
+$color-srs-3: hsl(163deg 85% 64%);
+$color-srs-4: hsl(206deg 92% 46%);
+$color-srs-5: hsl(244deg 100% 82%);
+$color-srs-6: hsl(247deg 72% 63%);
+$color-danger: hsl(0deg 85% 65%);
+$color-success: hsl(160deg 80% 45%);
+$color-stroke-inactive: hsl(0deg 0% 33%);
+$color-dot-base: hsl(0deg 0% 27%);
--- a/client/src/styles/abstracts/variables/_effects.scss
+++ b/client/src/styles/abstracts/variables/_effects.scss
@@ -0,0 +1,30 @@
+@use 'sass:color';
+@use 'colors' as *;
+
+$opacity-disabled: 0.5;
+$opacity-inactive: 0.3;
+$opacity-hover: 0.8;
+$opacity-active: 1;
+$blur-sm: blur(4px);
+$blur-md: blur(10px);
+$blur-lg: blur(20px);
+$bg-glass-subtle: hsl(0deg 0% 100% / 5%);
+$bg-glass-light: hsl(0deg 0% 100% / 6%);
+$bg-glass-strong: hsl(0deg 0% 100% / 10%);
+$bg-glass-dark: hsl(0deg 0% 0% / 20%);
+$shadow-sm: 0 2px 4px hsl(0deg 0% 0% / 20%);
+$shadow-md: 0 4px 15px hsl(0deg 0% 0% / 30%);
+$shadow-lg: 0 20px 50px hsl(0deg 0% 0% / 50%);
+$shadow-inset: inset 0 0 20px hsl(0deg 0% 0% / 30%);
+$text-shadow: 0 2px 10px hsl(0deg 0% 0% / 50%);
+$shadow-glow-xs: 0 0 4px hsl(0deg 0% 100% / 50%);
+$shadow-glow-base: 0 0 20px color.change($color-primary, $alpha: 0.4);
+$shadow-glow-hover: 0 0 40px color.change($color-primary, $alpha: 0.6);
+$shadow-glow-active: 0 0 20px color.change($color-primary, $alpha: 0.4);
+$dist-slide-sm: 10px;
+$duration-fast: 0.2s;
+$duration-normal: 0.3s;
+$duration-slow: 0.5s;
+$duration-chart: 1s;
+$ease-default: ease;
+$ease-out-back: cubic-bezier(0.175, 0.885, 0.32, 1.275);
--- a/client/src/styles/abstracts/variables/_layout.scss
+++ b/client/src/styles/abstracts/variables/_layout.scss
@@ -0,0 +1,46 @@
+@use 'colors' as *;
+
+$radius-sm: 4px;
+$radius-md: 8px;
+$radius-lg: 12px;
+$radius-xl: 24px;
+$radius-pill: 999px;
+$radius-circle: 50%;
+$border-width-sm: 1px;
+$border-width-md: 2px;
+$border-subtle: $border-width-sm solid $color-border;
+$border-focus: $border-width-md solid $color-primary;
+$border-transparent: $border-width-md solid transparent;
+$z-back: -1;
+$z-normal: 1;
+$z-sticky: 10;
+$z-dropdown: 50;
+$z-modal: 100;
+$z-tooltip: 200;
+$z-above: 2;
+$size-canvas: 300px;
+$size-kanji-preview: 200px;
+$size-icon-btn: 32px;
+$size-icon-small: 18px;
+$stroke-width-main: 3px;
+$stroke-width-arrow: 2px;
+$font-size-svg-number: 5px;
+$radius-xs: 2px;
+$radius-sm: 4px;
+$radius-md: 8px;
+$radius-lg: 12px;
+$radius-xl: 24px;
+$radius-pill: 999px;
+$radius-circle: 50%;
+$size-legend-box: 12px;
+$size-streak-dot: 24px;
+$size-srs-track: 24px;
+$size-chart-height: 160px;
+$size-ghost-min-height: 80px;
+$max-width-heatmap: 950px;
+$max-width-desktop: 1400px;
+$padding-page-y: 40px;
+$padding-page-x: 24px;
+$breakpoint-md: 960px;
+$offset-fab: 20px;
+$size-heatmap-cell-height: 10px;
--- a/client/src/styles/abstracts/variables/_spacing.scss
+++ b/client/src/styles/abstracts/variables/_spacing.scss
@@ -0,0 +1,10 @@
+$spacing-2xs: 2px;
+$spacing-xs: 4px;
+$spacing-sm: 8px;
+$spacing-md: 16px;
+$spacing-lg: 24px;
+$spacing-xl: 32px;
+$spacing-xxl: 48px;
+$size-loading-spinner: 64px;
+$gap-heatmap: 3px;
+$size-card-min: 60px;
--- a/client/src/styles/abstracts/variables/_typography.scss
+++ b/client/src/styles/abstracts/variables/_typography.scss
@@ -0,0 +1,25 @@
+$font-family-sans:
+	'Inter',
+	system-ui,
+	-apple-system,
+	sans-serif;
+$font-family-mono: 'Fira Code', monospace;
+$font-xs: 0.75rem;
+$font-sm: 0.875rem;
+$font-md: 1rem;
+$font-lg: 1.25rem;
+$font-xl: 1.5rem;
+$font-2xl: 2rem;
+$font-3xl: 3rem;
+$weight-regular: 400;
+$weight-medium: 500;
+$weight-bold: 700;
+$weight-black: 900;
+$tracking-tighter: -0.05em;
+$tracking-tight: -0.025em;
+$tracking-normal: 0em;
+$tracking-wide: 0.025em;
+$tracking-wider: 0.05em;
+$leading-tight: 1.2;
+$leading-normal: 1.5;
+$leading-loose: 1.8;
--- a/client/src/styles/base/_typography.scss
+++ b/client/src/styles/base/_typography.scss
@@ -0,0 +1,23 @@
+@use '../abstracts/variables' as *;
+
+body {
+	font-family: $font-family-sans;
+	line-height: $leading-normal;
+	-webkit-font-smoothing: antialiased;
+}
+
+h1,
+h2,
+h3,
+h4,
+h5,
+h6 {
+	font-weight: $weight-bold;
+	line-height: $leading-tight;
+	letter-spacing: $tracking-tight;
+}
+
+code,
+pre {
+	font-family: $font-family-mono;
+}
--- a/client/src/styles/components/_buttons.scss
+++ b/client/src/styles/components/_buttons.scss
@@ -0,0 +1,26 @@
+@use '../abstracts/variables' as *;
+
+.glow-btn {
+	box-shadow: $shadow-glow-base;
+	transition:
+		transform $duration-fast $ease-default,
+		box-shadow $duration-fast $ease-default;
+	will-change: transform, box-shadow;
+
+	&:hover {
+		transform: translateY(-2px);
+		box-shadow: $shadow-glow-hover;
+	}
+
+	&:active {
+		transform: translateY(0);
+		box-shadow: $shadow-glow-active;
+	}
+
+	&:disabled {
+		box-shadow: none;
+		transform: none;
+		opacity: $opacity-disabled;
+		cursor: not-allowed;
+	}
+}
--- a/client/src/styles/components/_kanji.scss
+++ b/client/src/styles/components/_kanji.scss
@@ -0,0 +1,147 @@
+@use '../abstracts/variables' as *;
+@use '../abstracts/mixins' as *;
+
+.canvas-container {
+	position: relative;
+
+	@include flex-center;
+
+	margin-bottom: $spacing-xl;
+}
+
+.canvas-wrapper {
+	width: $size-canvas;
+	height: $size-canvas;
+	border-radius: $radius-lg;
+	background: rgba($color-surface, 0.95);
+	border: $border-width-md solid $color-surface-light;
+	position: relative;
+	cursor: crosshair;
+	box-shadow: $shadow-inset;
+
+	canvas {
+		position: absolute;
+		top: 0;
+		left: 0;
+		width: 100%;
+		height: 100%;
+		touch-action: none;
+	}
+}
+
+.loading-text {
+	position: absolute;
+	color: $color-text-grey;
+	z-index: $z-sticky;
+	font-size: $font-sm;
+	font-weight: $weight-medium;
+	letter-spacing: $tracking-wide;
+}
+
+.svg-container {
+	width: $size-kanji-preview;
+	height: $size-kanji-preview;
+	margin: 0 auto $spacing-lg;
+	background: rgba($color-bg-dark, 0.2);
+	border-radius: $radius-md;
+	border: $border-subtle;
+	position: relative;
+
+	@include flex-center;
+
+	overflow: hidden;
+}
+
+.stroke-path {
+	fill: none;
+	stroke: $color-stroke-inactive;
+	stroke-width: $stroke-width-main;
+	stroke-linecap: round;
+	stroke-linejoin: round;
+	transition: stroke $duration-normal;
+
+	&.hidden {
+		opacity: 0;
+	}
+
+	&.animating {
+		stroke: $color-primary;
+		stroke-dasharray: var(--len);
+		stroke-dashoffset: var(--len);
+		animation: draw-stroke var(--duration) linear forwards;
+	}
+
+	&.drawn {
+		stroke: $color-text-white;
+		opacity: 1;
+	}
+}
+
+@keyframes draw-stroke {
+	to {
+		stroke-dashoffset: 0;
+	}
+}
+
+.stroke-start-circle {
+	fill: $color-srs-1;
+}
+
+.stroke-number {
+	fill: $color-text-white;
+	font-size: $font-size-svg-number;
+	font-family: $font-family-sans;
+	font-weight: $weight-bold;
+	text-anchor: middle;
+	dominant-baseline: middle;
+	pointer-events: none;
+}
+
+.stroke-arrow-line {
+	fill: none;
+	stroke: rgba($color-secondary, 0.7);
+	stroke-width: $stroke-width-arrow;
+	stroke-linecap: round;
+	stroke-linejoin: round;
+}
+
+.loading-spinner {
+	color: $color-text-grey;
+	font-size: $font-sm;
+}
+
+.play-btn {
+	position: absolute;
+	top: $spacing-sm;
+	right: $spacing-sm;
+	background: rgba($color-bg-dark, 0.3);
+	border: $border-width-sm solid rgba($color-primary, 0.5);
+	color: $color-primary;
+	border-radius: $radius-circle;
+	width: $size-icon-btn;
+	height: $size-icon-btn;
+
+	@include flex-center;
+
+	cursor: pointer;
+	transition: all $duration-fast ease;
+	z-index: $z-sticky;
+	backdrop-filter: $blur-sm;
+
+	&:hover {
+		transform: scale(1.1);
+		background: $color-primary;
+		color: $color-bg-dark;
+		border-color: $color-primary;
+		box-shadow: $shadow-glow-base;
+	}
+
+	&:active {
+		transform: scale(0.95);
+	}
+
+	svg {
+		width: $size-icon-small;
+		height: $size-icon-small;
+	}
+}
--- a/client/src/styles/components/_widgets.scss
+++ b/client/src/styles/components/_widgets.scss
@@ -0,0 +1,174 @@
+@use '../abstracts/variables' as *;
+@use '../abstracts/mixins' as *;
+@use 'sass:color';
+
+.widget-card {
+	@include card-base;
+
+	border: $border-subtle;
+}
+
+.level-0 {
+	background-color: $bg-glass-subtle;
+}
+
+.level-1 {
+	background-color: color.mix($color-primary, $color-surface, 25%);
+}
+
+.level-2 {
+	background-color: color.mix($color-primary, $color-surface, 50%);
+}
+
+.level-3 {
+	background-color: $color-primary;
+}
+
+.level-4 {
+	background-color: color.scale($color-primary, $lightness: 40%);
+}
+
+.heatmap-container {
+	width: 100%;
+
+	@include flex-center;
+}
+
+.heatmap-year {
+	display: grid;
+	grid-template-columns: repeat(53, 1fr);
+	gap: $gap-heatmap;
+	width: 100%;
+}
+
+.heatmap-week {
+	display: grid;
+	grid-template-rows: repeat(7, max-content);
+	gap: $gap-heatmap;
+}
+
+.heatmap-day-wrapper {
+	width: 100%;
+}
+
+.heatmap-cell {
+	width: 100%;
+	height: $size-heatmap-cell-height;
+	border-radius: $radius-xs;
+	transition:
+		opacity $duration-fast,
+		background-color $duration-fast;
+
+	&:hover {
+		opacity: $opacity-hover;
+	}
+}
+
+.today-cell {
+	border: $border-width-sm solid $color-text-white;
+	box-shadow: $shadow-glow-xs;
+	z-index: $z-above;
+	position: relative;
+	box-sizing: border-box;
+}
+
+.legend-container {
+	display: flex;
+	align-items: center;
+	gap: $spacing-xs;
+}
+
+.legend-box {
+	width: $size-legend-box;
+	height: $size-legend-box;
+	border-radius: $radius-xs;
+}
+
+.ghost-card {
+	background: $bg-glass-subtle;
+	border-radius: $radius-md;
+	padding: $spacing-sm;
+	text-align: center;
+	border: $border-width-sm solid $bg-glass-subtle;
+	display: flex;
+	flex-direction: column;
+	justify-content: center;
+	min-height: $size-ghost-min-height;
+}
+
+.srs-chart-container {
+	height: $size-chart-height;
+	width: 100%;
+}
+
+.srs-column {
+	height: 100%;
+	display: flex;
+	flex-direction: column;
+	justify-content: flex-end;
+}
+
+.srs-track {
+	width: $size-srs-track;
+	flex-grow: 1;
+	background: $bg-glass-light;
+	border-radius: $radius-md;
+	position: relative;
+	overflow: hidden;
+	display: flex;
+	align-items: flex-end;
+	margin: $spacing-xs 0;
+}
+
+.srs-fill {
+	width: 100%;
+	border-radius: $radius-sm;
+	transition: height 1s $ease-out-back;
+	min-height: 0;
+}
+
+.transition-text {
+	transition: color $duration-normal $ease-default;
+}
+
+.streak-dot {
+	width: $size-streak-dot;
+	height: $size-streak-dot;
+	border-radius: $radius-circle;
+	background: $bg-glass-strong;
+
+	@include flex-center;
+
+	transition: all $duration-normal;
+
+	&.active {
+		background: $color-primary;
+		box-shadow: $shadow-glow-active;
+	}
+}
+
+.forecast-list {
+	overflow-y: auto;
+
+	@include scrollbar;
+}
+
+.gap-1 {
+	gap: $spacing-xs;
+}
+
+.gap-2 {
+	gap: $spacing-sm;
+}
+
+.border-subtle {
+	border: $border-subtle;
+}
+
+.border-b-subtle {
+	border-bottom: $border-subtle;
+}
+
+.border-t-subtle {
+	border-top: $border-subtle;
+}
--- a/client/src/styles/main.scss
+++ b/client/src/styles/main.scss
@@ -0,0 +1,10 @@
+@use 'abstracts/variables';
+@use 'abstracts/mixins';
+@use 'base/typography';
+@use 'components/buttons';
+@use 'components/widgets';
+@use 'components/kanji';
+@use 'pages/app';
+@use 'pages/dashboard';
+@use 'pages/review';
+@use 'pages/collection';
--- a/client/src/styles/pages/_app.scss
+++ b/client/src/styles/pages/_app.scss
@@ -0,0 +1,61 @@
+@use '../abstracts/variables' as *;
+
+:root {
+	--v-theme-background: #{$color-bg-dark};
+}
+
+body,
+html,
+.zen-app,
+.v-application {
+	background-color: $color-bg-dark !important;
+	font-family: $font-family-sans;
+	color: $color-text-white;
+}
+
+.v-navigation-drawer {
+	background-color: $color-surface !important;
+
+	// stylelint-disable-next-line selector-class-pattern
+	.v-list-item--active {
+		background-color: rgba($color-primary, 0.15);
+		color: $color-primary !important;
+
+		.v-icon {
+			color: $color-primary !important;
+		}
+	}
+}
+
+.v-card {
+	box-shadow: $shadow-lg !important;
+}
+
+.app-bar-blur {
+	border-bottom-color: $color-border !important;
+	backdrop-filter: $blur-md;
+}
+
+.cursor-pointer {
+	cursor: pointer;
+}
+
+.tracking-wide {
+	letter-spacing: $tracking-wider;
+}
+
+.tracking-tight {
+	letter-spacing: $tracking-tight;
+}
+
+.border-subtle {
+	border: $border-subtle;
+}
+
+.logo-hover {
+	transition: opacity $duration-fast $ease-default;
+
+	&:hover {
+		opacity: $opacity-hover;
+	}
+}
--- a/client/src/styles/pages/_collection.scss
+++ b/client/src/styles/pages/_collection.scss
@@ -0,0 +1,128 @@
+@use '../abstracts/variables' as *;
+@use '../abstracts/mixins' as *;
+
+.sticky-search {
+	position: sticky;
+	top: $spacing-sm;
+	z-index: $z-sticky;
+	box-shadow: $shadow-md;
+	border-radius: $radius-sm;
+}
+
+.fade-slide-up {
+	@include animate-fade-up;
+}
+
+.kanji-grid {
+	display: grid;
+	grid-template-columns: repeat(auto-fill, minmax($size-card-min, 1fr));
+	gap: $spacing-sm;
+}
+
+.kanji-card {
+	@include card-base;
+	@include hover-lift;
+
+	aspect-ratio: 1;
+
+	@include flex-column;
+
+	align-items: center;
+	justify-content: center;
+	position: relative;
+	overflow: hidden;
+
+	.k-char {
+		font-size: $font-2xl;
+		font-weight: $weight-medium;
+		line-height: $leading-tight;
+		transition: all 0.3s ease;
+	}
+
+	&.zen-master {
+		border: 1px solid rgb(255 215 0 / 50%);
+		background: linear-gradient(135deg, rgb(30 30 36 / 100%) 0%, rgb(45 45 55 / 100%) 100%);
+		box-shadow: 0 0 15px rgb(255 215 0 / 15%);
+		animation: zen-pulse 4s infinite ease-in-out;
+
+		.k-char {
+			text-shadow: 0 0 15px rgb(255 215 0 / 60%);
+			transform: scale(1.1);
+		}
+	}
+
+	.k-dots {
+		display: flex;
+		gap: $spacing-2xs;
+		margin-top: $spacing-xs;
+
+		.dot {
+			width: $spacing-xs;
+			height: $spacing-xs;
+			border-radius: $radius-circle;
+			background: $color-dot-base;
+		}
+	}
+
+	.k-bars {
+		display: flex;
+		gap: 3px;
+		width: 60%;
+		height: 4px;
+		margin-top: $spacing-sm;
+
+		.bar {
+			flex: 1;
+			background: rgb(255 255 255 / 10%);
+			border-radius: 2px;
+			transition: background-color 0.3s ease;
+
+			&.filled {
+				box-shadow: 0 0 4px rgb(0 0 0 / 30%);
+			}
+		}
+	}
+}
+
+@keyframes zen-pulse {
+	0% {
+		box-shadow: 0 0 10px rgb(255 215 0 / 10%);
+		border-color: rgb(255 215 0 / 30%);
+	}
+
+	50% {
+		box-shadow: 0 0 20px rgb(255 215 0 / 30%);
+		border-color: rgb(255 215 0 / 80%);
+	}
+
+	100% {
+		box-shadow: 0 0 10px rgb(255 215 0 / 10%);
+		border-color: rgb(255 215 0 / 30%);
+	}
+}
+
+.readings-container {
+	display: grid;
+	grid-template-columns: 1fr 1fr;
+	gap: $spacing-sm;
+	text-align: left;
+
+	.reading-group {
+		background: $bg-glass-dark;
+		padding: $spacing-sm $spacing-md;
+		border-radius: $radius-md;
+
+		.reading-label {
+			font-size: $font-xs;
+			color: $color-text-grey;
+			text-transform: uppercase;
+			letter-spacing: $tracking-wider;
+			margin-bottom: $spacing-2xs;
+		}
+
+		.reading-value {
+			color: $color-text-white;
+			font-size: $font-sm;
+		}
+	}
+}
--- a/client/src/styles/pages/_dashboard.scss
+++ b/client/src/styles/pages/_dashboard.scss
@@ -0,0 +1,34 @@
+@use '../abstracts/variables' as *;
+@use '../abstracts/mixins' as *;
+
+.dashboard-layout {
+	display: grid;
+	grid-template-columns: repeat(3, 1fr);
+	grid-auto-rows: min-content;
+	gap: $spacing-lg;
+	width: 100%;
+	max-width: $max-width-desktop;
+	margin: 0 auto;
+	padding: $padding-page-y $padding-page-x;
+	box-sizing: border-box;
+
+	&.fade-in {
+		@include animate-fade-up($duration-slow);
+	}
+
+	.grid-area-full {
+		grid-column: 1 / -1;
+	}
+
+	.stats-split-layout {
+		grid-column: 1 / -1;
+		gap: $spacing-lg;
+
+		@include grid-responsive($breakpoint-md);
+
+		.stats-left,
+		.stats-right {
+			@include flex-column($spacing-lg);
+		}
+	}
+}
--- a/client/src/styles/pages/_review.scss
+++ b/client/src/styles/pages/_review.scss
@@ -0,0 +1,47 @@
+@use '../abstracts/variables' as *;
+
+.text-shadow {
+	text-shadow: $text-shadow;
+}
+
+.canvas-wrapper {
+	position: relative;
+	width: $size-canvas;
+	height: $size-canvas;
+	border-radius: $radius-lg;
+	background: $bg-glass-dark;
+	box-shadow: $shadow-inset;
+
+	.next-fab {
+		position: absolute;
+		bottom: -#{$offset-fab};
+		right: -#{$offset-fab};
+		z-index: $z-sticky;
+	}
+}
+
+.scale-enter-active,
+.scale-leave-active {
+	transition: all $duration-normal $ease-out-back;
+}
+
+.scale-enter-from,
+.scale-leave-to {
+	opacity: 0;
+	transform: scale(0);
+}
+
+.fade-slide-enter-active,
+.fade-slide-leave-active {
+	transition: all $duration-normal $ease-default;
+}
+
+.fade-slide-enter-from {
+	opacity: 0;
+	transform: translateY($dist-slide-sm);
+}
+
+.fade-slide-leave-to {
+	opacity: 0;
+	transform: translateY(-#{$dist-slide-sm});
+}
--- a/client/src/views/Collection.vue
+++ b/client/src/views/Collection.vue
@@ -0,0 +1,181 @@
+<template lang="pug">
+  v-container
+    v-text-field.mb-6.sticky-search(
+      v-model="searchQuery"
+      prepend-inner-icon="mdi-magnify"
+      :label="$t('collection.searchLabel')"
+      :placeholder="$t('collection.placeholder')"
+      variant="solo-filled"
+      density="comfortable"
+      bg-color="#2f3542"
+      color="white"
+      hide-details
+      clearable
+    )
+
+    .text-center.mt-10(v-if="loading") {{ $t('collection.loading') }}
+
+    .text-center.mt-10.text-grey-lighten-1(
+      v-else-if="!loading && Object.keys(groupedItems).length === 0"
+    )
+      v-icon.mb-4(size="64" color="grey-darken-2") mdi-text-search-variant
+      .text-h6 {{ $t('collection.noMatches') }}
+      .text-body-2 {{ $t('collection.tryDifferent') }}
+
+    .mb-6.fade-slide-up(
+      v-else
+      v-for="(group, level) in groupedItems"
+      :key="level"
+    )
+      .text-subtitle-2.text-grey.mb-2.font-weight-bold.ml-1
+        | {{ $t('collection.levelHeader') }} {{ level }}
+
+      .kanji-grid
+        .kanji-card(
+          v-for="item in group"
+          :key="item._id"
+          :class="{ 'zen-master': item.srsLevel >= 10 }"
+          @click="openDetail(item)"
+        )
+          .k-char(:style="{ color: item.srsLevel >= 10 ? '#ffd700' : getSRSColor(item.srsLevel) }")
+            | {{ item.char }}
+
+          .k-dots(v-if="item.srsLevel <= 6")
+            .dot(
+              v-for="n in 5"
+              :key="n"
+              :class="{ filled: n < item.srsLevel }"
+              :style="{ background: n < item.srsLevel ? getSRSColor(item.srsLevel) : '' }"
+            )
+
+          .k-bars(v-else-if="item.srsLevel < 10")
+            .bar(
+              :class="{ filled: item.srsLevel >= 7 }"
+              :style="{ background: item.srsLevel >= 7 ? getSRSColor(item.srsLevel) : '' }"
+            )
+            .bar(
+              :class="{ filled: item.srsLevel >= 8 }"
+              :style="{ background: item.srsLevel >= 8 ? getSRSColor(item.srsLevel) : '' }"
+            )
+            .bar(
+              :class="{ filled: item.srsLevel >= 9 }"
+              :style="{ background: item.srsLevel >= 9 ? getSRSColor(item.srsLevel) : '' }"
+            )
+
+    v-dialog(
+      v-model="showModal"
+      max-width="400"
+      transition="dialog-bottom-transition"
+    )
+      v-card.pa-4.pt-6.text-center.rounded-xl.border-subtle(color="#1e1e24")
+        .d-flex.justify-space-between.align-center.px-2.mb-2
+          .text-caption.text-grey {{ $t('review.level') }} {{ selectedItem?.level }}
+          v-chip.font-weight-bold(
+            size="x-small"
+            :color="getSRSColor(selectedItem?.srsLevel)"
+            variant="flat"
+          ) {{ getNextReviewText(selectedItem?.nextReview, selectedItem?.srsLevel) }}
+
+        .text-h2.font-weight-bold.mb-1 {{ selectedItem?.char }}
+        .text-subtitle-1.text-grey-lighten-1.text-capitalize.mb-4 {{ selectedItem?.meaning }}
+
+        KanjiSvgViewer(
+          v-if="showModal && selectedItem"
+          :char="selectedItem.char"
+        )
+
+        .readings-container.mb-4
+          .reading-group(v-if="hasReading(selectedItem?.onyomi)")
+            .reading-label {{ $t('collection.onyomi') }}
+            .reading-value {{ selectedItem?.onyomi.join(', ') }}
+
+          .reading-group(v-if="hasReading(selectedItem?.kunyomi)")
+            .reading-label {{ $t('collection.kunyomi') }}
+            .reading-value {{ selectedItem?.kunyomi.join(', ') }}
+
+          .reading-group(v-if="hasReading(selectedItem?.nanori)")
+            .reading-label {{ $t('collection.nanori') }}
+            .reading-value {{ selectedItem?.nanori.join(', ') }}
+
+        v-btn.text-white(
+          block
+          color="#2f3542"
+          @click="showModal = false"
+        ) {{ $t('collection.close') }}
+</template>
+
+<script setup>
+import { computed, onMounted, ref } from 'vue';
+import { useAppStore } from '@/stores/appStore';
+import { useI18n } from 'vue-i18n';
+import KanjiSvgViewer from '@/components/kanji/KanjiSvgViewer.vue';
+
+const { t } = useI18n();
+const store = useAppStore();
+
+const loading = ref(true);
+const showModal = ref(false);
+const selectedItem = ref(null);
+const searchQuery = ref('');
+
+onMounted(async () => {
+	await store.fetchCollection();
+	loading.value = false;
+});
+
+const filteredCollection = computed(() => {
+	if (!searchQuery.value) return store.collection;
+	const q = searchQuery.value.toLowerCase().trim();
+
+	return store.collection.filter(item => {
+		if (item.meaning && item.meaning.toLowerCase().includes(q)) return true;
+		if (item.char && item.char.includes(q)) return true;
+		if (item.onyomi && item.onyomi.some(r => r.includes(q))) return true;
+		if (item.kunyomi && item.kunyomi.some(r => r.includes(q))) return true;
+		if (item.nanori && item.nanori.some(r => r.includes(q))) return true;
+		return false;
+	});
+});
+
+const groupedItems = computed(() => {
+	const groups = {};
+	filteredCollection.value.forEach(i => {
+		if (!groups[i.level]) groups[i.level] = [];
+		groups[i.level].push(i);
+	});
+	return groups;
+});
+
+const SRS_COLORS = {
+	1: '#ff7675', 2: '#fdcb6e', 3: '#55efc4',
+	4: '#0984e3', 5: '#a29bfe', 6: '#6c5ce7',
+	7: '#00cec9', 8: '#fd79a8', 9: '#e84393',
+	10: '#ffd700'
+};
+
+const getSRSColor = (lvl) => SRS_COLORS[lvl] || '#444';
+
+const openDetail = (item) => {
+	selectedItem.value = item;
+	showModal.value = true;
+};
+
+const hasReading = (arr) => arr && arr.length > 0;
+
+const getNextReviewText = (dateStr, srsLvl) => {
+	if (srsLvl >= 10) return 'COMPLETE';
+	const date = new Date(dateStr);
+	const now = new Date();
+	if (date <= now) return t('stats.availableNow');
+
+	const diffMs = date - now;
+	const diffHrs = Math.floor(diffMs / 3600000);
+
+	if (diffHrs < 24) return t('stats.inHours', { n: diffHrs }, diffHrs);
+
+	const diffDays = Math.floor(diffHrs / 24);
+	return `Next: ${diffDays}d`;
+};
+</script>
+
+<style lang="scss" src="@/styles/pages/_collection.scss" scoped></style>
--- a/client/src/views/Dashboard.vue
+++ b/client/src/views/Dashboard.vue
@@ -0,0 +1,81 @@
+<template lang="pug">
+  .dashboard-layout.fade-in
+    WidgetWelcome(
+      :queue-length="stats.queueLength"
+      :has-lower-levels="stats.hasLowerLevels"
+      :lower-level-count="stats.lowerLevelCount"
+      :forecast="stats.forecast"
+      @start="handleStart"
+    )
+
+    .grid-area-full(v-if="!loading")
+      WidgetHeatmap(:heatmap-data="stats.heatmap")
+
+    .stats-split-layout(v-if="!loading")
+      .stats-left.d-flex.flex-column.gap-4
+        WidgetGhosts(:ghosts="stats.ghosts")
+        WidgetDistribution(:distribution="stats.distribution")
+        WidgetGuruMastery(:distribution="stats.distribution")
+
+      .stats-right
+        WidgetAccuracy(:accuracy="stats.accuracy")
+        WidgetStreak(:streak="stats.streak")
+        WidgetForecast(:forecast="stats.forecast")
+
+    .grid-area-full.d-flex.justify-center.mt-12(v-if="loading")
+      v-progress-circular(
+        indeterminate
+        color="#00cec9"
+        size="64"
+      )
+</template>
+
+<script setup>
+import { ref, onMounted } from 'vue';
+import { useAppStore } from '@/stores/appStore';
+import { useRouter } from 'vue-router';
+
+import WidgetWelcome from '@/components/dashboard/WidgetWelcome.vue';
+import WidgetHeatmap from '@/components/dashboard/WidgetHeatmap.vue';
+import WidgetGhosts from '@/components/dashboard/WidgetGhosts.vue';
+import WidgetDistribution from '@/components/dashboard/WidgetDistribution.vue';
+import WidgetAccuracy from '@/components/dashboard/WidgetAccuracy.vue';
+import WidgetStreak from '@/components/dashboard/WidgetStreak.vue';
+import WidgetForecast from '@/components/dashboard/WidgetForecast.vue';
+import WidgetGuruMastery from '@/components/dashboard/WidgetGuruMastery.vue';
+
+const store = useAppStore();
+const router = useRouter();
+const loading = ref(true);
+
+const stats = ref({
+	queueLength: 0,
+	hasLowerLevels: false,
+	lowerLevelCount: 0,
+	distribution: {},
+	forecast: [],
+	ghosts: [],
+	accuracy: { total: 0, correct: 0 },
+	heatmap: {},
+	streak: { current: 0, history: [], shield: { ready: false } }
+});
+
+onMounted(async () => {
+	try {
+		const data = await store.fetchStats();
+		if (data) {
+			stats.value = { ...stats.value, ...data };
+		}
+	} catch (e) {
+		console.error("Dashboard Load Error:", e);
+	} finally {
+		loading.value = false;
+	}
+});
+
+function handleStart(mode) {
+	router.push({ path: '/review', query: { mode: mode } });
+}
+</script>
+
+<style lang="scss" src="@/styles/pages/_dashboard.scss" scoped></style>
--- a/client/src/views/Review.vue
+++ b/client/src/views/Review.vue
@@ -0,0 +1,238 @@
+<template lang="pug">
+  v-container.fill-height.justify-center.pa-4
+    v-fade-transition(mode="out-in")
+      v-card.pa-6.rounded-xl.elevation-10.border-subtle.d-flex.flex-column.align-center(
+        v-if="currentItem"
+        color="#1e1e24"
+        width="100%"
+        max-width="420"
+      )
+        .d-flex.align-center.w-100.mb-6
+          v-btn.mr-2(
+            icon="mdi-arrow-left"
+            variant="text"
+            color="grey"
+            to="/"
+            density="comfortable"
+          )
+          .text-caption.text-grey.font-weight-bold
+            | {{ sessionDone }} / {{ sessionTotal }}
+          v-spacer
+          v-chip.font-weight-bold(
+            size="small"
+            :color="getSRSColor(currentItem.srsLevel)"
+            variant="flat"
+          ) {{ $t('review.level') }} {{ currentItem.srsLevel }}
+
+        .text-center.mb-6
+          .text-caption.text-grey.text-uppercase.tracking-wide.mb-1
+            | {{ $t('review.meaning') }}
+          .text-h3.font-weight-bold.text-white.text-shadow
+            | {{ currentItem.meaning }}
+
+        .canvas-wrapper.mb-2
+          KanjiCanvas(
+            ref="kanjiCanvasRef"
+            :char="currentItem.char"
+            @complete="handleComplete"
+            @mistake="handleMistake"
+          )
+          transition(name="scale")
+            v-btn.next-fab.glow-btn.text-black(
+              v-if="showNext"
+              @click="next"
+              color="#00cec9"
+              icon="mdi-arrow-right"
+              size="large"
+              elevation="8"
+            )
+
+        .mb-4
+          v-btn.text-caption.font-weight-bold.opacity-80(
+            variant="text"
+            color="amber-lighten-1"
+            prepend-icon="mdi-lightbulb-outline"
+            size="small"
+            :disabled="showNext || statusCode === 'hint'"
+            @click="triggerHint"
+          ) Show Hint
+
+        v-sheet.d-flex.align-center.justify-center(
+          width="100%"
+          height="48"
+          color="transparent"
+        )
+          transition(name="fade-slide" mode="out-in")
+            .status-text.text-h6.font-weight-bold(
+              :key="statusCode"
+              :class="getStatusClass(statusCode)"
+            ) {{ $t('review.' + statusCode) }}
+
+        v-progress-linear.mt-4(
+          v-model="progressPercent"
+          color="#00cec9"
+          height="4"
+          rounded
+          style="opacity: 0.3;"
+        )
+
+      v-card.pa-8.rounded-xl.elevation-10.border-subtle.text-center(
+        v-else-if="sessionTotal > 0 && store.queue.length === 0"
+        color="#1e1e24"
+        width="100%"
+        max-width="400"
+      )
+        .mb-6
+          v-avatar(color="rgba(0, 206, 201, 0.1)" size="80")
+            v-icon(size="40" color="#00cec9") mdi-trophy
+
+        .text-h4.font-weight-bold.mb-2 {{ $t('review.sessionComplete') }}
+        .text-body-1.text-grey.mb-8 {{ $t('review.levelup') }}
+
+        v-row.mb-6
+          v-col.border-r.border-grey-darken-3(cols="6")
+            .text-h3.font-weight-bold.text-white {{ accuracy }}%
+            .text-caption.text-grey.text-uppercase.mt-1 {{ $t('stats.accuracy') }}
+          v-col(cols="6")
+            .text-h3.font-weight-bold.text-white {{ sessionCorrect }}
+            .text-caption.text-grey.text-uppercase.mt-1 {{ $t('stats.correct') }}
+
+        v-btn.text-black.font-weight-bold.glow-btn(
+          to="/dashboard"
+          block
+          color="#00cec9"
+          height="50"
+          rounded="lg"
+        ) {{ $t('review.back') }}
+
+      .text-center(v-else)
+        v-icon.mb-4(size="64" color="grey-darken-2") mdi-check-circle-outline
+        .text-h4.mb-2.text-white {{ $t('review.caughtUp') }}
+        .text-grey.mb-6 {{ $t('review.noReviews') }}
+        v-btn.font-weight-bold(
+          to="/dashboard"
+          color="#00cec9"
+          variant="tonal"
+        ) {{ $t('review.viewCollection') }}
+</template>
+
+<script setup>
+import { ref, onMounted, computed, watch } from 'vue';
+import { useAppStore } from '@/stores/appStore';
+import { useRoute } from 'vue-router';
+import KanjiCanvas from '@/components/kanji/KanjiCanvas.vue';
+
+const store = useAppStore();
+const route = useRoute();
+
+const currentItem = ref(null);
+const statusCode = ref('draw');
+const showNext = ref(false);
+const isFailure = ref(false);
+const kanjiCanvasRef = ref(null);
+
+const sessionTotal = ref(0);
+const sessionDone = ref(0);
+const sessionCorrect = ref(0);
+
+const accuracy = computed(() => {
+	if (sessionDone.value === 0) return 100;
+	return Math.round((sessionCorrect.value / sessionDone.value) * 100);
+});
+
+const progressPercent = computed(() => {
+	if (sessionTotal.value === 0) return 0;
+	return (sessionDone.value / sessionTotal.value) * 100;
+});
+
+onMounted(async () => {
+	const mode = route.query.mode || 'shuffled';
+	await store.fetchQueue(mode);
+
+	if (sessionTotal.value === 0 && store.queue.length > 0) {
+		sessionTotal.value = store.queue.length;
+	}
+	loadNext();
+});
+
+watch(() => store.batchSize, async () => {
+	resetSession();
+});
+
+async function resetSession() {
+	sessionDone.value = 0;
+	sessionCorrect.value = 0;
+	sessionTotal.value = 0;
+	currentItem.value = null;
+	const mode = route.query.mode || 'shuffled';
+	await store.fetchQueue(mode);
+	if (store.queue.length > 0) sessionTotal.value = store.queue.length;
+	loadNext();
+}
+
+function loadNext() {
+	if (store.queue.length === 0) {
+		currentItem.value = null;
+		return;
+	}
+	const idx = Math.floor(Math.random() * store.queue.length);
+	currentItem.value = store.queue[idx];
+
+	statusCode.value = "draw";
+	showNext.value = false;
+	isFailure.value = false;
+}
+
+function triggerHint() {
+	if (!kanjiCanvasRef.value) return;
+
+	isFailure.value = true;
+	statusCode.value = "hint";
+
+	kanjiCanvasRef.value.drawGuide(true);
+}
+
+function handleMistake(isHint) {
+	if (isHint) {
+		isFailure.value = true;
+		statusCode.value = "hint";
+	} else {
+		statusCode.value = "tryAgain";
+	}
+}
+
+function handleComplete() {
+	statusCode.value = "correct";
+	showNext.value = true;
+}
+
+async function next() {
+	if (!currentItem.value) return;
+
+	await store.submitReview(currentItem.value.wkSubjectId, !isFailure.value);
+
+	sessionDone.value++;
+	if (!isFailure.value) sessionCorrect.value++;
+	const index = store.queue.findIndex(i => i._id === currentItem.value._id);
+	if (index !== -1) {
+		store.queue.splice(index, 1);
+	}
+
+	loadNext();
+}
+
+const getSRSColor = (lvl) => {
+	const colors = { 1: '#ff7675', 2: '#fdcb6e', 3: '#55efc4', 4: '#0984e3', 5: '#a29bfe', 6: '#6c5ce7' };
+	return colors[lvl] || 'grey';
+};
+
+const getStatusClass = (status) => {
+	switch (status) {
+		case 'hint': return 'text-red-lighten-1';
+		case 'correct': return 'text-teal-accent-3';
+		default: return 'text-grey-lighten-1';
+	}
+};
+</script>
+
+<style lang="scss" src="@/styles/pages/_review.scss" scoped></style>
--- a/client/stylelint.config.js
+++ b/client/stylelint.config.js
@@ -0,0 +1,17 @@
+/** @type {import('stylelint').Config} */
+export default {
+  extends: [
+    'stylelint-config-standard-scss',
+    'stylelint-config-recommended-vue'
+  ],
+  ignoreFiles: [
+    '**/node_modules/**',
+    '**/dist/**',
+    '**/android/**'
+  ],
+  rules: {
+    'at-rule-no-unknown': null,
+    'scss/at-rule-no-unknown': true,
+    'no-empty-source': null,
+  }
+};
--- a/client/vite.config.js
+++ b/client/vite.config.js
@@ -0,0 +1,19 @@
+import { fileURLToPath, URL } from 'node:url'
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+
+export default defineConfig({
+	plugins: [vue()],
+	resolve: {
+		alias: {
+			'@': fileURLToPath(new URL('./src', import.meta.url))
+		}
+	},
+	css: {
+		preprocessorOptions: {
+			scss: {
+				additionalData: `@use "@/styles/abstracts/_variables.scss" as *; @use "@/styles/abstracts/_mixins.scss" as *;`
+			}
+		}
+	}
+})
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -0,0 +1,51 @@
+services:
+  mongo:
+    image: mongo:6
+    container_name: zen_mongo
+    restart: always
+    ports:
+      - "27017:27017"
+    volumes:
+      - mongo-data:/data/db
+    networks:
+      - zen-network
+
+  server:
+    build: ./server
+    container_name: zen_server
+    restart: always
+    ports:
+      - "3000:3000"
+    env_file:
+      - .env
+    depends_on:
+      - mongo
+    networks:
+      - zen-network
+    volumes:
+      - ./server:/app
+      - /app/node_modules
+
+  client:
+    build: 
+      context: ./client
+      target: dev-stage
+    container_name: zen_client
+    ports:
+      - "5173:5173"
+    env_file:
+      - .env
+    depends_on:
+      - server
+    networks:
+      - zen-network
+    volumes:
+      - ./client:/app
+      - /app/node_modules
+
+volumes:
+  mongo-data:
+
+networks:
+  zen-network:
+    driver: bridge
--- a/server/Dockerfile
+++ b/server/Dockerfile
@@ -0,0 +1,13 @@
+FROM node:24-alpine
+
+WORKDIR /app
+
+COPY package*.json ./
+
+RUN npm install
+
+COPY . .
+
+EXPOSE 3000
+
+CMD ["npm", "start"]
--- a/server/package-lock.json
+++ b/server/package-lock.json
--- a/server/package.json
+++ b/server/package.json
@@ -0,0 +1,25 @@
+{
+	"name": "zen-kanji-server",
+	"version": "1.0.0",
+	"type": "module",
+	"main": "server.js",
+	"scripts": {
+		"start": "node server.js",
+		"dev": "node --watch server.js",
+		"test": "vitest",
+		"test:cov": "vitest run --coverage"
+	},
+	"dependencies": {
+		"@fastify/cors": "^11.2.0",
+		"@fastify/jwt": "^10.0.0",
+		"cors": "^2.8.5",
+		"fastify": "^5.6.2",
+		"fastify-cors": "^6.0.3",
+		"mongoose": "^9.0.1",
+		"node-fetch": "^3.3.2"
+	},
+	"devDependencies": {
+		"@vitest/coverage-v8": "^4.0.16",
+		"vitest": "^4.0.16"
+	}
+}
--- a/server/server.js
+++ b/server/server.js
@@ -0,0 +1,73 @@
+import Fastify from 'fastify';
+import cors from '@fastify/cors';
+import jwt from '@fastify/jwt';
+import { PORT, JWT_SECRET } from './src/config/constants.js';
+import { connectDB } from './src/config/db.js';
+import routes from './src/routes/v1.js';
+import { User } from './src/models/User.js';
+
+const fastify = Fastify({ logger: true });
+
+await connectDB();
+
+const allowedOrigins = [
+	'http://localhost:5173',
+	'http://localhost',
+	'capacitor://localhost',
+	'https://10.0.2.2:5173',
+	'https://zenkanji.crylia.de'
+];
+
+if (process.env.CORS_ORIGINS) {
+	const prodOrigins = process.env.CORS_ORIGINS.split(',');
+	allowedOrigins.push(...prodOrigins);
+}
+
+await fastify.register(cors, {
+	origin: allowedOrigins,
+	methods: ['GET', 'POST', 'PUT', 'DELETE'],
+	credentials: true
+});
+
+await fastify.register(jwt, {
+	secret: JWT_SECRET
+});
+
+fastify.decorate('authenticate', async function (req, reply) {
+	try {
+		const payload = await req.jwtVerify();
+
+		const user = await User.findById(payload.userId);
+
+		if (!user) {
+			reply.code(401).send({ message: 'User not found', code: 'INVALID_USER' });
+			return;
+		}
+
+		if (payload.version !== user.tokenVersion) {
+			reply.code(401).send({ message: 'Session invalid', code: 'INVALID_SESSION' });
+			return;
+		}
+		if (payload.version !== user.tokenVersion) {
+			throw new Error('Session invalid');
+		}
+
+		req.user = user;
+
+	} catch (err) {
+		reply.code(401).send(err);
+	}
+});
+
+await fastify.register(routes);
+
+const start = async () => {
+	try {
+		await fastify.listen({ port: PORT, host: '0.0.0.0' });
+		console.log(`Server running at http://localhost:${PORT}`);
+	} catch (err) {
+		fastify.log.error(err);
+		process.exit(1);
+	}
+};
+start();
--- a/server/src/config/constants.js
+++ b/server/src/config/constants.js
@@ -0,0 +1,4 @@
+export const PORT = process.env.PORT || 3000;
+export const MONGO_URI = process.env.MONGO_URI || 'mongodb://mongo:27017/zenkanji';
+export const SRS_TIMINGS_HOURS = [0, 0, 4, 8, 23, 47];
+export const JWT_SECRET = process.env.JWT_SECRET;
--- a/server/src/config/db.js
+++ b/server/src/config/db.js
@@ -0,0 +1,12 @@
+import mongoose from 'mongoose';
+import { MONGO_URI } from './constants.js';
+
+export const connectDB = async () => {
+	try {
+		await mongoose.connect(MONGO_URI);
+		console.log('✅ Connected to MongoDB');
+	} catch (err) {
+		console.error('❌ MongoDB Connection Error:', err);
+		process.exit(1);
+	}
+};
--- a/server/src/controllers/auth.controller.js
+++ b/server/src/controllers/auth.controller.js
@@ -0,0 +1,28 @@
+import * as AuthService from '../services/auth.service.js';
+
+export const login = async (req, reply) => {
+	const { apiKey } = req.body;
+	if (!apiKey) return reply.code(400).send({ error: 'API Key required' });
+
+	try {
+		const user = await AuthService.loginUser(apiKey);
+
+		const token = await reply.jwtSign(
+			{ userId: user._id, version: user.tokenVersion },
+			{ expiresIn: '365d' }
+		);
+
+		return {
+			success: true,
+			token,
+			user: { settings: user.settings, stats: user.stats }
+		};
+	} catch (err) {
+		return reply.code(401).send({ error: err.message });
+	}
+};
+
+export const logout = async (req, reply) => {
+	await AuthService.logoutUser(req.user._id);
+	return { success: true };
+};
--- a/server/src/controllers/collection.controller.js
+++ b/server/src/controllers/collection.controller.js
@@ -0,0 +1,33 @@
+import { User } from '../models/User.js';
+import * as ReviewService from '../services/review.service.js';
+import * as StatsService from '../services/stats.service.js';
+import { StudyItem } from '../models/StudyItem.js';
+
+export const getCollection = async (req, reply) => {
+	const items = await StudyItem.find({ userId: req.user._id });
+	return reply.send(items);
+};
+
+export const getQueue = async (req, reply) => {
+	const { limit, sort } = req.query;
+	const queue = await ReviewService.getQueue(req.user, parseInt(limit) || 20, sort);
+	return reply.send(queue);
+};
+
+export const getStats = async (req, reply) => {
+	const stats = await StatsService.getUserStats(req.user);
+	return reply.send(stats);
+};
+
+export const updateSettings = async (req, reply) => {
+	const { batchSize, drawingAccuracy } = req.body;
+	const user = req.user;
+
+	if (!user.settings) user.settings = {};
+
+	if (batchSize) user.settings.batchSize = batchSize;
+	if (drawingAccuracy) user.settings.drawingAccuracy = drawingAccuracy;
+
+	await user.save();
+	return reply.send({ success: true, settings: user.settings });
+};
--- a/server/src/controllers/review.controller.js
+++ b/server/src/controllers/review.controller.js
@@ -0,0 +1,11 @@
+import * as ReviewService from '../services/review.service.js';
+
+export const submitReview = async (req, reply) => {
+	const { subjectId, success } = req.body;
+	try {
+		const result = await ReviewService.processReview(req.user, subjectId, success);
+		return reply.send(result);
+	} catch (err) {
+		return reply.code(404).send({ error: err.message });
+	}
+};
--- a/server/src/controllers/sync.controller.js
+++ b/server/src/controllers/sync.controller.js
@@ -0,0 +1,10 @@
+import * as SyncService from '../services/sync.service.js';
+
+export const sync = async (req, reply) => {
+	try {
+		const result = await SyncService.syncWithWaniKani(req.user);
+		return reply.send(result);
+	} catch (error) {
+		return reply.code(500).send({ error: error.message });
+	}
+};
--- a/server/src/models/ReviewLog.js
+++ b/server/src/models/ReviewLog.js
@@ -0,0 +1,10 @@
+import mongoose from 'mongoose';
+
+const reviewLogSchema = new mongoose.Schema({
+	userId: { type: mongoose.Schema.Types.ObjectId, ref: 'User', required: true },
+	date: { type: String, required: true },
+	count: { type: Number, default: 0 }
+});
+
+reviewLogSchema.index({ userId: 1, date: 1 }, { unique: true });
+export const ReviewLog = mongoose.model('ReviewLog', reviewLogSchema);
--- a/server/src/models/StudyItem.js
+++ b/server/src/models/StudyItem.js
@@ -0,0 +1,21 @@
+import mongoose from 'mongoose';
+
+const studyItemSchema = new mongoose.Schema({
+	userId: { type: mongoose.Schema.Types.ObjectId, ref: 'User', required: true },
+	wkSubjectId: { type: Number, required: true },
+	char: { type: String, required: true },
+	meaning: { type: String, required: true },
+	level: { type: Number, required: true },
+	srsLevel: { type: Number, default: 0 },
+	nextReview: { type: Date, default: Date.now },
+	onyomi: { type: [String], default: [] },
+	kunyomi: { type: [String], default: [] },
+	nanori: { type: [String], default: [] },
+	stats: {
+		correct: { type: Number, default: 0 },
+		total: { type: Number, default: 0 }
+	}
+});
+
+studyItemSchema.index({ userId: 1, wkSubjectId: 1 }, { unique: true });
+export const StudyItem = mongoose.model('StudyItem', studyItemSchema);
--- a/server/src/models/User.js
+++ b/server/src/models/User.js
@@ -0,0 +1,21 @@
+import mongoose from 'mongoose';
+
+const userSchema = new mongoose.Schema({
+	wkApiKey: { type: String, required: true, unique: true },
+	lastSync: { type: Date, default: Date.now },
+	settings: {
+		batchSize: { type: Number, default: 20 },
+		drawingAccuracy: { type: Number, default: 10 }
+	},
+	tokenVersion: { type: Number, default: 0 },
+	stats: {
+		totalReviews: { type: Number, default: 0 },
+		correctReviews: { type: Number, default: 0 },
+		currentStreak: { type: Number, default: 0 },
+		maxStreak: { type: Number, default: 0 },
+		lastStudyDate: { type: String, default: null },
+		lastFreezeDate: { type: Date, default: null }
+	}
+});
+
+export const User = mongoose.model('User', userSchema);
--- a/server/src/routes/v1.js
+++ b/server/src/routes/v1.js
@@ -0,0 +1,22 @@
+import { login, logout } from '../controllers/auth.controller.js';
+import { sync } from '../controllers/sync.controller.js';
+import { submitReview } from '../controllers/review.controller.js';
+import { getStats, getQueue, getCollection, updateSettings } from '../controllers/collection.controller.js';
+
+async function routes(fastify, options) {
+	fastify.post('/api/auth/login', login);
+
+	fastify.register(async (privateParams) => {
+		privateParams.addHook('onRequest', fastify.authenticate);
+
+		privateParams.post('/api/auth/logout', logout);
+		privateParams.post('/api/sync', sync);
+		privateParams.post('/api/review', submitReview);
+		privateParams.get('/api/stats', getStats);
+		privateParams.get('/api/queue', getQueue);
+		privateParams.get('/api/collection', getCollection);
+		privateParams.post('/api/settings', updateSettings);
+	});
+}
+
+export default routes;
--- a/server/src/services/auth.service.js
+++ b/server/src/services/auth.service.js
@@ -0,0 +1,29 @@
+import { User } from '../models/User.js';
+
+export const loginUser = async (apiKey) => {
+	const response = await fetch('https://api.wanikani.com/v2/user', {
+		headers: { Authorization: `Bearer ${apiKey}` }
+	});
+
+	if (response.status !== 200) {
+		throw new Error('Invalid API Key');
+	}
+
+	let user = await User.findOne({ wkApiKey: apiKey });
+
+	if (!user) {
+		user = await User.create({
+			wkApiKey: apiKey,
+			tokenVersion: 0,
+			stats: { totalReviews: 0, correctReviews: 0, currentStreak: 0, maxStreak: 0 },
+			settings: { batchSize: 20 }
+		});
+	}
+
+	return user;
+};
+
+export const logoutUser = async (userId) => {
+	await User.findByIdAndUpdate(userId, { $inc: { tokenVersion: 1 } });
+	return true;
+};
--- a/server/src/services/review.service.js
+++ b/server/src/services/review.service.js
@@ -0,0 +1,85 @@
+import { ReviewLog } from '../models/ReviewLog.js';
+import { StudyItem } from '../models/StudyItem.js';
+import { getDaysDiff, getSRSDate } from '../utils/dateUtils.js';
+
+export const processReview = async (user, subjectId, success) => {
+	if (!user.stats) user.stats = { totalReviews: 0, correctReviews: 0, currentStreak: 0, maxStreak: 0 };
+	user.stats.totalReviews += 1;
+	if (success) user.stats.correctReviews += 1;
+
+	const todayStr = new Date().toISOString().split('T')[0];
+	const lastStudyStr = user.stats.lastStudyDate;
+
+	if (lastStudyStr !== todayStr) {
+		if (!lastStudyStr) {
+			user.stats.currentStreak = 1;
+		} else {
+			const diff = getDaysDiff(lastStudyStr, todayStr);
+			if (diff === 1) {
+				user.stats.currentStreak += 1;
+			} else if (diff > 1) {
+				const lastFreeze = user.stats.lastFreezeDate ? new Date(user.stats.lastFreezeDate) : null;
+				let daysSinceFreeze = 999;
+				if (lastFreeze) daysSinceFreeze = getDaysDiff(lastFreeze.toISOString().split('T')[0], todayStr);
+
+				const canUseShield = daysSinceFreeze >= 7;
+
+				if (canUseShield && diff === 2) {
+					console.log(`User ${user._id} saved by Zen Shield!`);
+					user.stats.lastFreezeDate = new Date();
+					user.stats.currentStreak += 1;
+				} else {
+					user.stats.currentStreak = 1;
+				}
+			}
+		}
+		user.stats.lastStudyDate = todayStr;
+		if (user.stats.currentStreak > user.stats.maxStreak) user.stats.maxStreak = user.stats.currentStreak;
+	}
+	await user.save();
+
+	await ReviewLog.findOneAndUpdate(
+		{ userId: user._id, date: todayStr },
+		{ $inc: { count: 1 } },
+		{ upsert: true, new: true }
+	);
+
+	const item = await StudyItem.findOne({ userId: user._id, wkSubjectId: subjectId });
+	if (!item) throw new Error('Item not found');
+
+	if (!item.stats) item.stats = { correct: 0, total: 0 };
+	item.stats.total += 1;
+	if (success) item.stats.correct += 1;
+
+	if (success) {
+		const nextLevel = Math.min(item.srsLevel + 1, 10);
+		item.srsLevel = nextLevel;
+		item.nextReview = getSRSDate(nextLevel);
+	} else {
+		item.srsLevel = Math.max(1, item.srsLevel - 1);
+		item.nextReview = Date.now();
+	}
+
+	await item.save();
+	return { nextReview: item.nextReview, srsLevel: item.srsLevel };
+};
+
+export const getQueue = async (user, limit = 100, sortMode) => {
+	const query = {
+		userId: user._id,
+		srsLevel: { $lt: 10, $gt: 0 },
+		nextReview: { $lte: new Date() }
+	};
+
+	let dueItems;
+	if (sortMode === 'priority') {
+		dueItems = await StudyItem.find(query).sort({ srsLevel: 1, level: 1 }).limit(limit);
+	} else {
+		dueItems = await StudyItem.find(query).limit(limit);
+		for (let i = dueItems.length - 1; i > 0; i--) {
+			const j = Math.floor(Math.random() * (i + 1));
+			[dueItems[i], dueItems[j]] = [dueItems[j], dueItems[i]];
+		}
+	}
+	return dueItems;
+};
--- a/server/src/services/stats.service.js
+++ b/server/src/services/stats.service.js
@@ -0,0 +1,112 @@
+import { StudyItem } from '../models/StudyItem.js';
+import { ReviewLog } from '../models/ReviewLog.js';
+import { getDaysDiff } from '../utils/dateUtils.js';
+
+export const getUserStats = async (user) => {
+	const userId = user._id;
+
+	const srsCounts = await StudyItem.aggregate([
+		{ $match: { userId: userId } },
+		{ $group: { _id: "$srsLevel", count: { $sum: 1 } } }
+	]);
+	const dist = { 1: 0, 2: 0, 3: 0, 4: 0, 5: 0, 6: 0 };
+	srsCounts.forEach(g => { if (dist[g._id] !== undefined) dist[g._id] = g.count; });
+
+	const now = new Date();
+	const next24h = new Date(now.getTime() + 24 * 60 * 60 * 1000);
+	const upcoming = await StudyItem.find({
+		userId: userId,
+		srsLevel: { $lt: 6, $gt: 0 },
+		nextReview: { $lte: next24h }
+	}).select('nextReview');
+
+	const forecast = new Array(24).fill(0);
+	upcoming.forEach(item => {
+		const diff = Math.floor((new Date(item.nextReview) - now) / 3600000);
+		if (diff < 0) forecast[0]++;
+		else if (diff < 24) forecast[diff]++;
+	});
+
+	const queueItems = await StudyItem.find({
+		userId: userId,
+		srsLevel: { $lt: 6, $gt: 0 },
+		nextReview: { $lte: now }
+	}).select('srsLevel');
+	const queueCount = queueItems.length;
+
+	let hasLowerLevels = false;
+	let lowerLevelCount = 0;
+	if (queueCount > 0) {
+		const levels = queueItems.map(i => i.srsLevel);
+		const minSrs = Math.min(...levels);
+		const maxSrs = Math.max(...levels);
+		if (minSrs < maxSrs) {
+			hasLowerLevels = true;
+			lowerLevelCount = queueItems.filter(i => i.srsLevel === minSrs).length;
+		}
+	}
+
+	const oneYearAgo = new Date();
+	oneYearAgo.setDate(oneYearAgo.getDate() - 365);
+	const dateStr = oneYearAgo.toISOString().split('T')[0];
+	const logs = await ReviewLog.find({ userId: userId, date: { $gte: dateStr } });
+	const heatmap = {};
+	logs.forEach(l => { heatmap[l.date] = l.count; });
+
+	const todayStr = new Date().toISOString().split('T')[0];
+	const lastStudyStr = user.stats.lastStudyDate || null;
+	let displayStreak = user.stats.currentStreak || 0;
+
+	if (lastStudyStr) {
+		const diff = getDaysDiff(lastStudyStr, todayStr);
+		if (diff > 1) displayStreak = 0;
+	}
+
+	const lastFreeze = user.stats.lastFreezeDate ? new Date(user.stats.lastFreezeDate) : null;
+	let daysSinceFreeze = 999;
+	if (lastFreeze) {
+		daysSinceFreeze = getDaysDiff(lastFreeze.toISOString().split('T')[0], todayStr);
+	}
+
+	const shieldReady = daysSinceFreeze >= 7;
+	const shieldCooldown = shieldReady ? 0 : (7 - daysSinceFreeze);
+
+	const history7Days = [];
+	for (let i = 6; i >= 0; i--) {
+		const d = new Date();
+		d.setDate(d.getDate() - i);
+		const dStr = d.toISOString().split('T')[0];
+		const count = heatmap[dStr] || 0;
+		history7Days.push({ date: dStr, active: count > 0 });
+	}
+
+	const allGhosts = await StudyItem.find({ userId: userId, 'stats.total': { $gte: 2 } })
+		.select('char meaning stats srsLevel');
+
+	const sortedGhosts = allGhosts.map(item => ({
+		...item.toObject(),
+		accuracy: Math.round((item.stats.correct / item.stats.total) * 100)
+	})).filter(i => i.accuracy < 85)
+		.sort((a, b) => a.accuracy - b.accuracy)
+		.slice(0, 4);
+
+	return {
+		distribution: dist,
+		forecast: forecast,
+		queueLength: queueCount,
+		hasLowerLevels,
+		lowerLevelCount,
+		heatmap: heatmap,
+		ghosts: sortedGhosts,
+		streak: {
+			current: displayStreak,
+			best: user.stats.maxStreak || 0,
+			shield: { ready: shieldReady, cooldown: Math.max(0, shieldCooldown) },
+			history: history7Days
+		},
+		accuracy: {
+			total: user.stats.totalReviews || 0,
+			correct: user.stats.correctReviews || 0
+		}
+	};
+};
--- a/server/src/services/sync.service.js
+++ b/server/src/services/sync.service.js
@@ -0,0 +1,78 @@
+import { User } from '../models/User.js';
+import { StudyItem } from '../models/StudyItem.js';
+
+export const syncWithWaniKani = async (user) => {
+	const apiKey = user.wkApiKey;
+
+	if (!apiKey) {
+		throw new Error('User has no WaniKani API Key');
+	}
+
+	console.log(`Starting sync for user: ${user._id}`);
+
+	let allSubjectIds = [];
+	let nextUrl = 'https://api.wanikani.com/v2/assignments?subject_types=kanji&started=true';
+
+	try {
+		while (nextUrl) {
+			const res = await fetch(nextUrl, {
+				headers: { Authorization: `Bearer ${apiKey}` }
+			});
+
+			if (!res.ok) {
+				throw new Error(`WaniKani API Error: ${res.statusText}`);
+			}
+
+			const json = await res.json();
+			allSubjectIds = allSubjectIds.concat(json.data.map(d => d.data.subject_id));
+			nextUrl = json.pages.next_url;
+		}
+	} catch (err) {
+		console.error("Error fetching assignments:", err);
+		throw new Error("Failed to connect to WaniKani. Check your internet connection.");
+	}
+
+	if (allSubjectIds.length === 0) {
+		return { count: 0, message: "No unlocked kanji found.", settings: user.settings };
+	}
+
+	const existingItems = await StudyItem.find({ userId: user._id }).select('wkSubjectId');
+	const existingIds = new Set(existingItems.map(i => i.wkSubjectId));
+	const newIds = allSubjectIds.filter(id => !existingIds.has(id));
+
+	console.log(`Found ${newIds.length} new items to download.`);
+
+	const CHUNK_SIZE = 100;
+	for (let i = 0; i < newIds.length; i += CHUNK_SIZE) {
+		const chunk = newIds.slice(i, i + CHUNK_SIZE);
+
+		const subRes = await fetch(`https://api.wanikani.com/v2/subjects?ids=${chunk.join(',')}`, {
+			headers: { Authorization: `Bearer ${apiKey}` }
+		});
+		const subJson = await subRes.json();
+
+		const operations = subJson.data.map(d => {
+			const readings = d.data.readings || [];
+			return {
+				userId: user._id,
+				wkSubjectId: d.id,
+				char: d.data.characters,
+				meaning: d.data.meanings.find(m => m.primary)?.meaning || 'Unknown',
+				level: d.data.level,
+				srsLevel: 1,
+				nextReview: Date.now(),
+				onyomi: readings.filter(r => r.type === 'onyomi').map(r => r.reading),
+				kunyomi: readings.filter(r => r.type === 'kunyomi').map(r => r.reading),
+				nanori: readings.filter(r => r.type === 'nanori').map(r => r.reading),
+				stats: { correct: 0, total: 0 }
+			};
+		});
+
+		if (operations.length > 0) {
+			await StudyItem.insertMany(operations);
+		}
+	}
+
+	const finalCount = await StudyItem.countDocuments({ userId: user._id });
+	return { success: true, count: finalCount, settings: user.settings };
+};
--- a/server/src/utils/dateUtils.js
+++ b/server/src/utils/dateUtils.js
@@ -0,0 +1,32 @@
+export const getDaysDiff = (date1Str, date2Str) => {
+	const d1 = new Date(date1Str);
+	const d2 = new Date(date2Str);
+	const diff = d2 - d1;
+	return Math.floor(diff / (1000 * 60 * 60 * 24));
+};
+
+export const getSRSDate = (level) => {
+	const now = new Date();
+	let hoursToAdd = 0;
+
+	switch (level) {
+		case 1: hoursToAdd = 4; break;
+		case 2: hoursToAdd = 8; break;
+		case 3: hoursToAdd = 24; break;
+		case 4: hoursToAdd = 2 * 24; break;
+		case 5: hoursToAdd = 7 * 24; break;
+		case 6: hoursToAdd = 14 * 24; break;
+
+		case 7: hoursToAdd = 7 * 24; break;
+		case 8: hoursToAdd = 30 * 24; break;
+		case 9: hoursToAdd = 90 * 24; break;
+
+		case 10: break;
+		default: hoursToAdd = 4;
+	}
+
+	if (hoursToAdd === 0) return null;
+
+	now.setUTCHours(now.getUTCHours() + hoursToAdd);
+	return now;
+};
--- a/server/tests/services/auth.service.test.js
+++ b/server/tests/services/auth.service.test.js
@@ -0,0 +1,52 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { loginUser, logoutUser } from '../../src/services/auth.service.js';
+import { User } from '../../src/models/User.js';
+
+vi.mock('../../src/models/User.js');
+global.fetch = vi.fn();
+
+describe('Auth Service', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('loginUser', () => {
+		it('should throw error for invalid API Key', async () => {
+			fetch.mockResolvedValue({ status: 401 });
+			await expect(loginUser('bad_key')).rejects.toThrow('Invalid API Key');
+		});
+
+		it('should return existing user if found', async () => {
+			fetch.mockResolvedValue({ status: 200 });
+			const mockUser = { wkApiKey: 'valid_key', _id: '123' };
+			User.findOne.mockResolvedValue(mockUser);
+
+			const result = await loginUser('valid_key');
+			expect(result).toEqual(mockUser);
+			expect(User.create).not.toHaveBeenCalled();
+		});
+
+		it('should create new user if not found', async () => {
+			fetch.mockResolvedValue({ status: 200 });
+			User.findOne.mockResolvedValue(null);
+			const newUser = { wkApiKey: 'valid_key', _id: 'new_id' };
+			User.create.mockResolvedValue(newUser);
+
+			const result = await loginUser('valid_key');
+			expect(result).toEqual(newUser);
+			expect(User.create).toHaveBeenCalledWith(expect.objectContaining({
+				wkApiKey: 'valid_key',
+				tokenVersion: 0
+			}));
+		});
+	});
+
+	describe('logoutUser', () => {
+		it('should increment token version', async () => {
+			User.findByIdAndUpdate.mockResolvedValue(true);
+			const result = await logoutUser('userId');
+			expect(User.findByIdAndUpdate).toHaveBeenCalledWith('userId', { $inc: { tokenVersion: 1 } });
+			expect(result).toBe(true);
+		});
+	});
+});
--- a/server/tests/services/controllers.test.js
+++ b/server/tests/services/controllers.test.js
@@ -0,0 +1,142 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import * as AuthController from '../../src/controllers/auth.controller.js';
+import * as ReviewController from '../../src/controllers/review.controller.js';
+import * as SyncController from '../../src/controllers/sync.controller.js';
+import * as CollectionController from '../../src/controllers/collection.controller.js';
+
+import * as AuthService from '../../src/services/auth.service.js';
+import * as ReviewService from '../../src/services/review.service.js';
+import * as SyncService from '../../src/services/sync.service.js';
+import * as StatsService from '../../src/services/stats.service.js';
+import { StudyItem } from '../../src/models/StudyItem.js';
+
+vi.mock('../../src/services/auth.service.js');
+vi.mock('../../src/services/review.service.js');
+vi.mock('../../src/services/sync.service.js');
+vi.mock('../../src/services/stats.service.js');
+vi.mock('../../src/models/StudyItem.js');
+
+const mockReq = (body = {}, user = {}, query = {}) => ({ body, user, query });
+const mockReply = () => {
+	const res = {};
+	res.code = vi.fn().mockReturnValue(res);
+	res.send = vi.fn().mockReturnValue(res);
+	res.jwtSign = vi.fn().mockResolvedValue('token');
+	return res;
+};
+
+describe('Controllers', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('Auth Controller', () => {
+		it('login should fail without apiKey', async () => {
+			const reply = mockReply();
+			await AuthController.login(mockReq({}), reply);
+			expect(reply.code).toHaveBeenCalledWith(400);
+		});
+
+		it('login should succeed', async () => {
+			const reply = mockReply();
+			AuthService.loginUser.mockResolvedValue({ _id: 1, tokenVersion: 1 });
+			await AuthController.login(mockReq({ apiKey: 'key' }), reply);
+			expect(reply.jwtSign).toHaveBeenCalled();
+			expect(reply.code).not.toHaveBeenCalledWith(401);
+		});
+
+		it('login should catch errors', async () => {
+			const reply = mockReply();
+			AuthService.loginUser.mockRejectedValue(new Error('fail'));
+			await AuthController.login(mockReq({ apiKey: 'k' }), reply);
+			expect(reply.code).toHaveBeenCalledWith(401);
+		});
+
+		it('logout should succeed', async () => {
+			const reply = mockReply();
+			await AuthController.logout(mockReq({}, { _id: 1 }), reply);
+			expect(AuthService.logoutUser).toHaveBeenCalled();
+		});
+	});
+
+	describe('Review Controller', () => {
+		it('submitReview should succeed', async () => {
+			const reply = mockReply();
+			ReviewService.processReview.mockResolvedValue({});
+			await ReviewController.submitReview(mockReq({}), reply);
+			expect(reply.send).toHaveBeenCalled();
+		});
+
+		it('submitReview should handle error', async () => {
+			const reply = mockReply();
+			ReviewService.processReview.mockRejectedValue(new Error('err'));
+			await ReviewController.submitReview(mockReq({}), reply);
+			expect(reply.code).toHaveBeenCalledWith(404);
+		});
+	});
+
+	describe('Sync Controller', () => {
+		it('sync should succeed', async () => {
+			const reply = mockReply();
+			SyncService.syncWithWaniKani.mockResolvedValue({});
+			await SyncController.sync(mockReq({}, {}), reply);
+			expect(reply.send).toHaveBeenCalled();
+		});
+
+		it('sync should handle error', async () => {
+			const reply = mockReply();
+			SyncService.syncWithWaniKani.mockRejectedValue(new Error('err'));
+			await SyncController.sync(mockReq({}, {}), reply);
+			expect(reply.code).toHaveBeenCalledWith(500);
+		});
+	});
+
+	describe('Collection Controller', () => {
+		it('getCollection should return items', async () => {
+			const reply = mockReply();
+			StudyItem.find.mockResolvedValue([]);
+			await CollectionController.getCollection(mockReq({}, { _id: 1 }), reply);
+			expect(reply.send).toHaveBeenCalledWith([]);
+		});
+
+		it('getQueue should call service with default limit', async () => {
+			const reply = mockReply();
+			ReviewService.getQueue.mockResolvedValue([]);
+			await CollectionController.getQueue(mockReq({}, {}, {}), reply);
+			expect(ReviewService.getQueue).toHaveBeenCalledWith(expect.anything(), 20, undefined);
+		});
+
+		it('getQueue should call service with provided limit', async () => {
+			const reply = mockReply();
+			ReviewService.getQueue.mockResolvedValue([]);
+			await CollectionController.getQueue(mockReq({}, {}, { limit: '50' }), reply);
+			expect(ReviewService.getQueue).toHaveBeenCalledWith(expect.anything(), 50, undefined);
+		});
+
+		it('getStats should call service', async () => {
+			const reply = mockReply();
+			StatsService.getUserStats.mockResolvedValue({});
+			await CollectionController.getStats(mockReq({}, {}), reply);
+			expect(StatsService.getUserStats).toHaveBeenCalled();
+		});
+
+		it('updateSettings should initialize settings if missing', async () => {
+			const reply = mockReply();
+			const save = vi.fn();
+			const user = { save };
+			await CollectionController.updateSettings(mockReq({ batchSize: 50 }, user), reply);
+			expect(user.settings).toBeDefined();
+			expect(user.settings.batchSize).toBe(50);
+			expect(save).toHaveBeenCalled();
+		});
+
+		it('updateSettings should update drawingAccuracy', async () => {
+			const reply = mockReply();
+			const save = vi.fn();
+			const user = { settings: {}, save };
+			await CollectionController.updateSettings(mockReq({ drawingAccuracy: 5 }, user), reply);
+			expect(user.settings.drawingAccuracy).toBe(5);
+			expect(save).toHaveBeenCalled();
+		});
+	});
+});
--- a/server/tests/services/review.service.test.js
+++ b/server/tests/services/review.service.test.js
@@ -0,0 +1,144 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import * as ReviewService from '../../src/services/review.service.js';
+import { User } from '../../src/models/User.js';
+import { ReviewLog } from '../../src/models/ReviewLog.js';
+import { StudyItem } from '../../src/models/StudyItem.js';
+
+vi.mock('../../src/models/ReviewLog.js');
+vi.mock('../../src/models/StudyItem.js');
+
+describe('Review Service', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.setSystemTime(new Date('2023-01-10T00:00:00Z'));
+	});
+
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.resetAllMocks();
+	});
+
+	describe('processReview', () => {
+		const mockUser = (stats = {}) => ({
+			_id: 'u1',
+			stats: { ...stats },
+			save: vi.fn()
+		});
+
+		const mockItem = (srs = 1) => ({
+			userId: 'u1',
+			wkSubjectId: 100,
+			srsLevel: srs,
+			stats: { correct: 0, total: 0 },
+			save: vi.fn(),
+			nextReview: null
+		});
+
+		it('should throw error if item not found', async () => {
+			const user = mockUser();
+			StudyItem.findOne.mockResolvedValue(null);
+
+			await expect(ReviewService.processReview(user, 999, true))
+				.rejects.toThrow('Item not found');
+
+			expect(StudyItem.findOne).toHaveBeenCalledWith({
+				userId: user._id,
+				wkSubjectId: 999
+			});
+		});
+
+		it('should handle standard success flow', async () => {
+			const user = mockUser();
+			delete user.stats;
+			StudyItem.findOne.mockResolvedValue(mockItem());
+			const res = await ReviewService.processReview(user, 100, true);
+			expect(user.save).toHaveBeenCalled();
+			expect(res.srsLevel).toBe(2);
+		});
+
+		it('should handle failure flow', async () => {
+			const user = mockUser();
+			const item = mockItem(2);
+			StudyItem.findOne.mockResolvedValue(item);
+			await ReviewService.processReview(user, 100, false);
+			expect(item.srsLevel).toBe(1);
+		});
+
+		it('should increment streak (diff = 1)', async () => {
+			const user = mockUser({ lastStudyDate: '2023-01-09', currentStreak: 5 });
+			StudyItem.findOne.mockResolvedValue(mockItem());
+			await ReviewService.processReview(user, 100, true);
+			expect(user.stats.currentStreak).toBe(6);
+		});
+
+		it('should maintain streak (diff = 0)', async () => {
+			const user = mockUser({ lastStudyDate: '2023-01-10', currentStreak: 5 });
+			StudyItem.findOne.mockResolvedValue(mockItem());
+			await ReviewService.processReview(user, 100, true);
+			expect(user.stats.currentStreak).toBe(5);
+		});
+
+		it('should reset streak (diff > 1, no shield)', async () => {
+			const user = mockUser({ lastStudyDate: '2023-01-08', currentStreak: 5, lastFreezeDate: '2023-01-09' });
+			StudyItem.findOne.mockResolvedValue(mockItem());
+			await ReviewService.processReview(user, 100, true);
+			expect(user.stats.currentStreak).toBe(1);
+		});
+
+		it('should use shield (diff = 2, shield ready)', async () => {
+			const user = mockUser({ lastStudyDate: '2023-01-08', currentStreak: 5, lastFreezeDate: '2022-01-01' });
+			StudyItem.findOne.mockResolvedValue(mockItem());
+			await ReviewService.processReview(user, 100, true);
+			expect(user.stats.currentStreak).toBe(6);
+			expect(user.stats.lastFreezeDate).toBeDefined();
+		});
+
+		it('should use shield (diff = 2) when lastFreezeDate is undefined', async () => {
+			const user = mockUser({ lastStudyDate: '2023-01-08', currentStreak: 5 });
+			user.stats.lastFreezeDate = null;
+
+			StudyItem.findOne.mockResolvedValue(mockItem());
+
+			await ReviewService.processReview(user, 100, true);
+
+			expect(user.stats.currentStreak).toBe(6);
+			expect(user.stats.lastFreezeDate).toBeDefined();
+		});
+
+		it('should initialize item stats if missing', async () => {
+			const user = mockUser();
+			const item = mockItem();
+			delete item.stats;
+			StudyItem.findOne.mockResolvedValue(item);
+
+			await ReviewService.processReview(user, 100, true);
+
+			expect(item.stats).toEqual(expect.objectContaining({ correct: 1, total: 1 }));
+		});
+
+		it('should not break on time travel (diff < 0)', async () => {
+			const user = mockUser({ lastStudyDate: '2023-01-11', currentStreak: 5 });
+			StudyItem.findOne.mockResolvedValue(mockItem());
+
+			await ReviewService.processReview(user, 100, true);
+
+			expect(user.stats.lastStudyDate).toBe('2023-01-10');
+			expect(user.stats.currentStreak).toBe(5);
+		});
+	});
+
+	describe('getQueue', () => {
+		it('should sort by priority', async () => {
+			const mockFind = { sort: vi.fn().mockReturnThis(), limit: vi.fn().mockResolvedValue([]) };
+			StudyItem.find.mockReturnValue(mockFind);
+			await ReviewService.getQueue({ _id: 'u1' }, 10, 'priority');
+			expect(mockFind.sort).toHaveBeenCalled();
+		});
+		it('should shuffle (default)', async () => {
+			const mockFind = { limit: vi.fn().mockResolvedValue([1, 2]) };
+			StudyItem.find.mockReturnValue(mockFind);
+			await ReviewService.getQueue({ _id: 'u1' }, 10, 'random');
+			expect(mockFind.limit).toHaveBeenCalled();
+		});
+	});
+});
--- a/server/tests/services/stats.service.test.js
+++ b/server/tests/services/stats.service.test.js
@@ -0,0 +1,147 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { getUserStats } from '../../src/services/stats.service.js';
+import { StudyItem } from '../../src/models/StudyItem.js';
+import { ReviewLog } from '../../src/models/ReviewLog.js';
+
+vi.mock('../../src/models/StudyItem.js');
+vi.mock('../../src/models/ReviewLog.js');
+
+describe('Stats Service', () => {
+	beforeEach(() => {
+		vi.useFakeTimers();
+		vi.setSystemTime(new Date('2023-01-10T12:00:00Z'));
+	});
+	afterEach(() => {
+		vi.useRealTimers();
+		vi.clearAllMocks();
+	});
+
+	const mockUser = {
+		_id: 'u1',
+		stats: {
+			totalReviews: 10,
+			correctReviews: 8,
+			currentStreak: 5,
+			lastStudyDate: '2023-01-10',
+			lastFreezeDate: '2022-01-01'
+		}
+	};
+
+	it('should calculate stats correctly including ghosts, forecast, and unknown SRS levels', async () => {
+		StudyItem.aggregate.mockResolvedValue([
+			{ _id: 1, count: 5 },
+			{ _id: 8, count: 2 }
+		]);
+
+		StudyItem.find.mockImplementation(() => ({
+			select: vi.fn().mockImplementation((fields) => {
+				if (fields.includes('nextReview')) {
+					const now = new Date();
+					return Promise.resolve([
+						{ nextReview: new Date(now.getTime() - 1000) },
+						{ nextReview: new Date(now.getTime() + 3600000) },
+						{ nextReview: new Date(now.getTime() + 24 * 3600000) }
+					]);
+				}
+				if (fields.includes('stats')) {
+					const mkGhost = (acc) => ({
+						char: 'A', meaning: 'B', stats: { correct: acc, total: 100 }, srsLevel: 1,
+						toObject: () => ({ char: 'A', meaning: 'B', stats: { correct: acc, total: 100 }, srsLevel: 1 })
+					});
+					return Promise.resolve([mkGhost(60), mkGhost(50), mkGhost(90)]);
+				}
+				if (fields.includes('srsLevel')) {
+					return Promise.resolve([{ srsLevel: 1 }, { srsLevel: 4 }]);
+				}
+				return Promise.resolve([]);
+			})
+		}));
+
+		ReviewLog.find.mockResolvedValue([
+			{ date: '2023-01-09', count: 5 }
+		]);
+
+		const stats = await getUserStats(mockUser);
+
+		expect(stats.forecast[0]).toBe(1);
+		expect(stats.forecast[1]).toBe(1);
+
+		expect(stats.ghosts.length).toBe(2);
+		expect(stats.ghosts[0].accuracy).toBe(50);
+		expect(stats.ghosts[1].accuracy).toBe(60);
+
+		expect(stats.distribution[1]).toBe(5);
+		expect(stats.distribution[8]).toBeUndefined();
+
+		expect(stats.heatmap['2023-01-09']).toBe(5);
+	});
+
+	it('should handle queue with same levels (hasLowerLevels = false)', async () => {
+		StudyItem.aggregate.mockResolvedValue([]);
+		StudyItem.find.mockImplementation(() => ({
+			select: vi.fn().mockImplementation((fields) => {
+				if (fields.includes('stats')) {
+					return Promise.resolve([]);
+				}
+
+				if (fields.includes('srsLevel')) {
+					return Promise.resolve([{ srsLevel: 2 }, { srsLevel: 2 }]);
+				}
+				return Promise.resolve([]);
+			})
+		}));
+		ReviewLog.find.mockResolvedValue([]);
+
+		const stats = await getUserStats(mockUser);
+		expect(stats.hasLowerLevels).toBe(false);
+	});
+
+	it('should calculate shield cooldown', async () => {
+		StudyItem.aggregate.mockResolvedValue([]);
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+		ReviewLog.find.mockResolvedValue([]);
+
+		const frozenUser = {
+			...mockUser,
+			stats: { ...mockUser.stats, lastFreezeDate: '2023-01-07' }
+		};
+
+		const stats = await getUserStats(frozenUser);
+		expect(stats.streak.shield.ready).toBe(false);
+		expect(stats.streak.shield.cooldown).toBe(4);
+	});
+
+	it('should handle streak logic when lastStudyDate is missing or old', async () => {
+		const userNoDate = { ...mockUser, stats: { ...mockUser.stats, lastStudyDate: null, currentStreak: 5 } };
+		StudyItem.aggregate.mockResolvedValue([]);
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+		ReviewLog.find.mockResolvedValue([]);
+
+		const res1 = await getUserStats(userNoDate);
+		expect(res1.streak.current).toBe(5);
+
+		const userMissed = { ...mockUser, stats: { ...mockUser.stats, lastStudyDate: '2023-01-08' } };
+		const res2 = await getUserStats(userMissed);
+		expect(res2.streak.current).toBe(0);
+	});
+
+	it('should handle missing user stats fields (null checks)', async () => {
+		const emptyUser = {
+			_id: 'u2',
+			stats: {}
+		};
+
+		StudyItem.aggregate.mockResolvedValue([]);
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+		ReviewLog.find.mockResolvedValue([]);
+
+		const stats = await getUserStats(emptyUser);
+
+		expect(stats.streak.current).toBe(0);
+		expect(stats.streak.best).toBe(0);
+		expect(stats.accuracy.total).toBe(0);
+		expect(stats.accuracy.correct).toBe(0);
+
+		expect(stats.streak.shield.ready).toBe(true);
+	});
+});
--- a/server/tests/services/sync.service.test.js
+++ b/server/tests/services/sync.service.test.js
@@ -0,0 +1,212 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { syncWithWaniKani } from '../../src/services/sync.service.js';
+import { StudyItem } from '../../src/models/StudyItem.js';
+
+vi.mock('../../src/models/StudyItem.js');
+global.fetch = vi.fn();
+
+describe('Sync Service', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	const mockUser = { _id: 'u1', wkApiKey: 'key', settings: {} };
+
+	it('should throw if no API key', async () => {
+		await expect(syncWithWaniKani({}))
+			.rejects.toThrow('User has no WaniKani API Key');
+	});
+
+	it('should handle API fetch error', async () => {
+		fetch.mockResolvedValue({ ok: false, statusText: 'Unauthorized' });
+		await expect(syncWithWaniKani(mockUser))
+			.rejects.toThrow('Failed to connect to WaniKani');
+	});
+
+	it('should return 0 if no unlocked kanji', async () => {
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({ data: [], pages: { next_url: null } })
+		});
+
+		const res = await syncWithWaniKani(mockUser);
+		expect(res.count).toBe(0);
+		expect(res.message).toContain('No unlocked kanji');
+	});
+
+	it('should sync new items with full reading data', async () => {
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [{ data: { subject_id: 101 } }],
+				pages: { next_url: null }
+			})
+		});
+
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [{
+					id: 101,
+					data: {
+						characters: 'A',
+						meanings: [{ primary: true, meaning: 'A_Meaning' }],
+						level: 5,
+						readings: [
+							{ type: 'onyomi', reading: 'on' },
+							{ type: 'kunyomi', reading: 'kun' },
+							{ type: 'nanori', reading: 'nan' }
+						]
+					}
+				}]
+			})
+		});
+
+		StudyItem.insertMany.mockResolvedValue(true);
+		StudyItem.countDocuments.mockResolvedValue(1);
+
+		await syncWithWaniKani(mockUser);
+
+		expect(StudyItem.insertMany).toHaveBeenCalledWith(expect.arrayContaining([
+			expect.objectContaining({
+				wkSubjectId: 101,
+				onyomi: ['on'],
+				kunyomi: ['kun'],
+				nanori: ['nan']
+			})
+		]));
+	});
+
+	it('should filter out existing items', async () => {
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [
+					{ data: { subject_id: 101 } },
+					{ data: { subject_id: 102 } }
+				],
+				pages: { next_url: null }
+			})
+		});
+
+		StudyItem.find.mockReturnValue({
+			select: vi.fn().mockResolvedValue([{ wkSubjectId: 102 }])
+		});
+
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [{
+					id: 101,
+					data: {
+						characters: 'New',
+						meanings: [],
+						level: 1,
+						readings: []
+					}
+				}]
+			})
+		});
+
+		StudyItem.insertMany.mockResolvedValue(true);
+		StudyItem.countDocuments.mockResolvedValue(2);
+
+		await syncWithWaniKani(mockUser);
+
+		expect(StudyItem.insertMany).toHaveBeenCalledTimes(1);
+		expect(StudyItem.insertMany).toHaveBeenCalledWith(expect.arrayContaining([
+			expect.objectContaining({ wkSubjectId: 101 })
+		]));
+		expect(StudyItem.insertMany).not.toHaveBeenCalledWith(expect.arrayContaining([
+			expect.objectContaining({ wkSubjectId: 102 })
+		]));
+	});
+
+	it('should handle assignment pagination', async () => {
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [{ data: { subject_id: 1 } }],
+				pages: { next_url: 'http://next-page' }
+			})
+		});
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [{ data: { subject_id: 2 } }],
+				pages: { next_url: null }
+			})
+		});
+
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({ data: [] })
+		});
+
+		StudyItem.countDocuments.mockResolvedValue(2);
+
+		await syncWithWaniKani(mockUser);
+
+		expect(fetch).toHaveBeenCalledTimes(3);
+	});
+
+	it('should skip insert if operations are empty (e.g. subject data missing)', async () => {
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: [{ data: { subject_id: 101 } }],
+				pages: { next_url: null }
+			})
+		});
+
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({ data: [] })
+		});
+
+		StudyItem.countDocuments.mockResolvedValue(0);
+
+		await syncWithWaniKani(mockUser);
+
+		expect(StudyItem.insertMany).not.toHaveBeenCalled();
+	});
+
+	it('should sync items in chunks', async () => {
+		const manyIds = Array.from({ length: 150 }, (_, i) => i + 1);
+		const subjectData = manyIds.map(id => ({ data: { subject_id: id } }));
+
+		fetch.mockResolvedValueOnce({
+			ok: true,
+			json: async () => ({
+				data: subjectData,
+				pages: { next_url: null }
+			})
+		});
+
+		StudyItem.find.mockReturnValue({ select: vi.fn().mockResolvedValue([]) });
+
+		fetch
+			.mockResolvedValueOnce({
+				ok: true,
+				json: async () => ({ data: [{ id: 1, data: { characters: 'C', meanings: [], level: 1 } }] })
+			})
+			.mockResolvedValueOnce({
+				ok: true,
+				json: async () => ({ data: [{ id: 101, data: { characters: 'D', meanings: [], level: 1 } }] })
+			});
+
+		StudyItem.insertMany.mockResolvedValue(true);
+		StudyItem.countDocuments.mockResolvedValue(150);
+
+		await syncWithWaniKani(mockUser);
+
+		expect(fetch).toHaveBeenCalledTimes(3);
+		expect(StudyItem.insertMany).toHaveBeenCalledTimes(2);
+	});
+});
--- a/server/tests/utils.test.js
+++ b/server/tests/utils.test.js
@@ -0,0 +1,54 @@
+import { describe, it, expect, vi, beforeAll, afterAll } from 'vitest';
+import { getDaysDiff, getSRSDate } from '../src/utils/dateUtils.js';
+
+describe('Date Utils', () => {
+	describe('getDaysDiff', () => {
+		it('should calculate difference between two dates correctly', () => {
+			const d1 = '2023-01-01';
+			const d2 = '2023-01-03';
+			expect(getDaysDiff(d1, d2)).toBe(2);
+		});
+
+		it('should return 0 for same day', () => {
+			expect(getDaysDiff('2023-01-01', '2023-01-01')).toBe(0);
+		});
+	});
+
+	describe('getSRSDate', () => {
+		beforeAll(() => {
+			vi.useFakeTimers();
+			vi.setSystemTime(new Date('2023-01-01T12:00:00Z'));
+		});
+
+		afterAll(() => {
+			vi.useRealTimers();
+		});
+
+		it('should add correct hours for levels 1-6', () => {
+			const base = new Date('2023-01-01T12:00:00Z');
+
+			expect(getSRSDate(1).toISOString()).toBe(new Date(base.getTime() + 4 * 3600000).toISOString());
+			expect(getSRSDate(2).toISOString()).toBe(new Date(base.getTime() + 8 * 3600000).toISOString());
+			expect(getSRSDate(3).toISOString()).toBe(new Date(base.getTime() + 24 * 3600000).toISOString());
+			expect(getSRSDate(4).toISOString()).toBe(new Date(base.getTime() + 48 * 3600000).toISOString());
+			expect(getSRSDate(5).toISOString()).toBe(new Date(base.getTime() + 7 * 24 * 3600000).toISOString());
+			expect(getSRSDate(6).toISOString()).toBe(new Date(base.getTime() + 14 * 24 * 3600000).toISOString());
+		});
+
+		it('should add correct hours for levels 7-9', () => {
+			const base = new Date('2023-01-01T12:00:00Z');
+			expect(getSRSDate(7).toISOString()).toBe(new Date(base.getTime() + 7 * 24 * 3600000).toISOString());
+			expect(getSRSDate(8).toISOString()).toBe(new Date(base.getTime() + 30 * 24 * 3600000).toISOString());
+			expect(getSRSDate(9).toISOString()).toBe(new Date(base.getTime() + 90 * 24 * 3600000).toISOString());
+		});
+
+		it('should return null for level 10 (burned)', () => {
+			expect(getSRSDate(10)).toBeNull();
+		});
+
+		it('should default to 4 hours for unknown levels', () => {
+			const base = new Date('2023-01-01T12:00:00Z');
+			expect(getSRSDate(99).toISOString()).toBe(new Date(base.getTime() + 4 * 3600000).toISOString());
+		});
+	});
+});