feat: per-workspace theme system with 5 theme options

Replaces in-memory darkMode toggle with persisted per-workspace theme
selection. Adds dark, nord, dracula, and solarized CSS theme definitions.
Theme is applied via data-theme attribute and derived isDark class.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tauri/src/App.svelte

@@ -12,7 +12,7 @@
   });
 </script>
 
-<div class={app.darkMode ? "dark" : ""}>
+<div class={app.isDark ? "dark" : ""} data-theme={app.currentTheme ?? ""}>
   <div class="h-screen w-screen" class:p-2={isLinux}>
     <div
       class="relative h-full w-full overflow-hidden bg-surface-light text-text-light dark:bg-surface-dark dark:text-text-dark"
@@ -30,7 +30,7 @@
       {/if}
 
       {#if app.screen === "setup"}
-        <SetupScreen />
+        <SetupScreen cancellable={app.hasWorkspace} />
       {:else}
         <TasksScreen />
       {/if}

apps/tauri/src/app.css

@@ -68,3 +68,68 @@ body {
   background-color: #242424;
   color: #e5e7eb;
 }
+
+/* ── Theme overrides ─────────────────────────────────────────────── */
+
+[data-theme="dark"] {
+  --color-primary: #2d87b8;
+  --color-primary-hover: #2474a0;
+  --color-surface-light: #242424;
+  --color-surface-dark: #242424;
+  --color-card-light: #303030;
+  --color-card-dark: #303030;
+  --color-text-light: #e5e7eb;
+  --color-text-dark: #e5e7eb;
+  --color-text-secondary-light: #9ca3af;
+  --color-text-secondary-dark: #9ca3af;
+  --color-border-light: #3d3d3d;
+  --color-border-dark: #3d3d3d;
+}
+
+[data-theme="nord"] {
+  --color-primary: #88c0d0;
+  --color-primary-hover: #7ab3c3;
+  --color-surface-light: #2e3440;
+  --color-surface-dark: #2e3440;
+  --color-card-light: #3b4252;
+  --color-card-dark: #3b4252;
+  --color-text-light: #eceff4;
+  --color-text-dark: #eceff4;
+  --color-text-secondary-light: #d8dee9;
+  --color-text-secondary-dark: #d8dee9;
+  --color-border-light: #434c5e;
+  --color-border-dark: #434c5e;
+  --color-danger: #bf616a;
+}
+
+[data-theme="dracula"] {
+  --color-primary: #bd93f9;
+  --color-primary-hover: #a87ef0;
+  --color-surface-light: #282a36;
+  --color-surface-dark: #282a36;
+  --color-card-light: #343746;
+  --color-card-dark: #343746;
+  --color-text-light: #f8f8f2;
+  --color-text-dark: #f8f8f2;
+  --color-text-secondary-light: #bfbfbf;
+  --color-text-secondary-dark: #bfbfbf;
+  --color-border-light: #44475a;
+  --color-border-dark: #44475a;
+  --color-danger: #ff5555;
+}
+
+[data-theme="solarized"] {
+  --color-primary: #268bd2;
+  --color-primary-hover: #1e7ac0;
+  --color-surface-light: #002b36;
+  --color-surface-dark: #002b36;
+  --color-card-light: #073642;
+  --color-card-dark: #073642;
+  --color-text-light: #93a1a1;
+  --color-text-dark: #93a1a1;
+  --color-text-secondary-light: #657b83;
+  --color-text-secondary-dark: #657b83;
+  --color-border-light: #094959;
+  --color-border-dark: #094959;
+  --color-danger: #dc322f;
+}

apps/tauri/src/lib/stores/app.svelte.ts

@@ -20,9 +20,7 @@ let config = $state<AppConfig | null>(null);
 let lists = $state<TaskList[]>([]);
 let activeListId = $state<string | null>(null);
 let tasks = $state<Task[]>([]);
-let darkMode = $state(
+let osDark = globalThis.matchMedia?.("(prefers-color-scheme: dark)").matches ?? false;
-  globalThis.matchMedia?.("(prefers-color-scheme: dark)").matches ?? false,
-);
 let syncing = $state(false);
 let syncMode = $state<"full" | "push" | "pull">("full");
 let lastSyncResult = $state<SyncResult | null>(null);
@@ -56,6 +54,16 @@ let hasWorkspace = $derived(
     Object.keys(config.workspaces).length > 0,
 );
 
+const DARK_THEMES = new Set(["dark", "nord", "dracula", "solarized"]);
+let currentTheme = $derived(
+  config?.current_workspace
+    ? config.workspaces[config.current_workspace]?.theme ?? null
+    : null,
+);
+let isDark = $derived(
+  currentTheme ? DARK_THEMES.has(currentTheme) : osDark,
+);
+
 // ── Actions ──────────────────────────────────────────────────────────
 
 async function loadConfig() {
@@ -311,8 +319,31 @@ function setSyncMode(mode: "full" | "push" | "pull") {
   syncMode = mode;
 }
 
-function toggleDarkMode() {
+async function setTheme(theme: string | null) {
-  darkMode = !darkMode;
+  if (!config?.current_workspace) return;
+  try {
+    await invoke("set_workspace_theme", {
+      workspaceName: config.current_workspace,
+      theme,
+    });
+    config = await invoke<AppConfig>("get_config");
+  } catch (e) {
+    error = String(e);
+  }
+}
+
+async function addWebdavWorkspace(name: string, webdavUrl: string, username: string, password: string) {
+  try {
+    await invoke("add_webdav_workspace", { name, webdavUrl, username, password });
+    config = await invoke<AppConfig>("get_config");
+    await loadLists();
+    const ws = config?.workspaces[name];
+    if (ws) invoke("watch_workspace", { path: ws.path }).catch((e) => console.warn("File watcher failed:", e));
+    screen = "tasks";
+    error = null;
+  } catch (e) {
+    error = String(e);
+  }
 }
 
 function setScreen(s: Screen) {
@@ -350,8 +381,11 @@ export const app = {
   get completedTasks() {
     return completedTasks;
   },
-  get darkMode() {
+  get currentTheme() {
-    return darkMode;
+    return currentTheme;
+  },
+  get isDark() {
+    return isDark;
   },
   get syncing() {
     return syncing;
@@ -388,7 +422,8 @@ export const app = {
   setGroupByDueDate,
   triggerSync,
   setSyncMode,
-  toggleDarkMode,
+  setTheme,
+  addWebdavWorkspace,
   setScreen,
   clearError,
 };