feat(themes): redesign theme picker with gradient cards + beefy mode selector

Replace the shared ThemePage component inside the Themes workbench
panel with a custom compact layout better suited to the narrow
(~300px) panel context. ThemePage was designed for a full-width
desktop route and reads as noisy/overloaded in a panel.

Mode selector (Hell/Dunkel/System) — primary-fill active state with
white icon+text (was subtle shadow-sm that barely registered in dark
mode), fill-weight icons when active, equal-width pill buttons in a
shared muted container.

Theme cards (Option D — "Farbton-Karte") — swap the 2×5 overlapping
color-dot preview for a large 16:10 gradient (primary → secondary in
the effective mode), theme name overlaid bottom-left with text-shadow,
subtle dark-overlay at the bottom for readability, white check badge
in the corner when active, 2px primary border + glow ring for the
active state. Hover lifts the card 1px. Renders all 8 variants
(default + extended) in a uniform 2-column grid.

Wallpaper tabs (Farben/Bilder/Upload + scope toggle) — restyle via
scoped :global() overrides to match the mode selector: muted pill
container, primary-fill active state, muted-foreground inactive.
Previously these used .bg-surface + .shadow-sm which was nearly
invisible against the panel background.

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

apps/mana/apps/web/src/lib/modules/themes/ListView.svelte

@@ -1,29 +1,106 @@
 <!--
-  Themes — Workbench-embedded theme picker with variant selection,
-  light/dark mode toggle, and wallpaper picker.
+  Themes — Workbench-embedded theme picker.
+
+  Custom layout tuned for the narrow panel (no shared ThemePage):
+  - Big gradient theme cards (primary → secondary) with overlay label
+  - Beefy mode selector (Hell / Dunkel / System)
+  - Wallpaper picker below in a 2-column grid
 -->
 <script lang="ts">
-	import { ThemePage } from '@mana/shared-theme-ui';
+	import { Sun, Moon, Desktop, Check } from '@mana/shared-icons';
+	import {
+		THEME_DEFINITIONS,
+		DEFAULT_THEME_VARIANTS,
+		EXTENDED_THEME_VARIANTS,
+		type ThemeVariant,
+		type ThemeMode,
+	} from '@mana/shared-theme';
 	import { theme } from '$lib/stores/theme';
 	import { wallpaperStore } from '$lib/stores/wallpaper.svelte';
 	import WallpaperPicker from '$lib/components/wallpaper/WallpaperPicker.svelte';
+
+	const modes: { id: ThemeMode; label: string; icon: typeof Sun }[] = [
+		{ id: 'light', label: 'Hell', icon: Sun },
+		{ id: 'dark', label: 'Dunkel', icon: Moon },
+		{ id: 'system', label: 'System', icon: Desktop },
+	];
+
+	/** Pick the light- or dark-mode palette based on the effective mode,
+	 *  so the preview card reflects what the app actually renders right
+	 *  now instead of a single canonical look. */
+	function paletteFor(variant: ThemeVariant) {
+		const def = THEME_DEFINITIONS[variant];
+		return theme.effectiveMode === 'dark' ? def.dark : def.light;
+	}
+
+	function gradientCss(variant: ThemeVariant): string {
+		const c = paletteFor(variant);
+		return `linear-gradient(135deg, hsl(${c.primary}) 0%, hsl(${c.secondary}) 100%)`;
+	}
+
+	let allVariants = $derived<ThemeVariant[]>([
+		...DEFAULT_THEME_VARIANTS,
+		...EXTENDED_THEME_VARIANTS,
+	]);
 </script>
 
 <div class="themes-page">
-	<ThemePage
-		currentVariant={theme.variant}
-		onSelectTheme={(v) => theme.setVariant(v)}
-		showModeSelector={true}
-		currentMode={theme.mode}
-		onModeChange={(m) => theme.setMode(m)}
-		showBackButton={false}
-		transparent={wallpaperStore.hasWallpaper}
-	>
-		<section class="wallpaper-section">
-			<h2 class="wallpaper-heading">Hintergrund</h2>
-			<WallpaperPicker />
-		</section>
-	</ThemePage>
+	<!-- ── Mode selector ──────────────────────────────────────────── -->
+	<section class="mode-section">
+		<h2 class="section-heading">Modus</h2>
+		<div class="mode-row" role="tablist">
+			{#each modes as m}
+				{@const isActive = theme.mode === m.id}
+				<button
+					type="button"
+					role="tab"
+					aria-selected={isActive}
+					class="mode-btn"
+					class:active={isActive}
+					onclick={() => theme.setMode(m.id)}
+				>
+					<m.icon size={16} weight={isActive ? 'fill' : 'regular'} />
+					<span>{m.label}</span>
+				</button>
+			{/each}
+		</div>
+	</section>
+
+	<!-- ── Theme cards ────────────────────────────────────────────── -->
+	<section class="themes-section">
+		<h2 class="section-heading">Aktuelles Theme</h2>
+		<div class="themes-grid">
+			{#each allVariants as variant (variant)}
+				{@const def = THEME_DEFINITIONS[variant]}
+				{@const isActive = theme.variant === variant}
+				<button
+					type="button"
+					class="theme-card"
+					class:active={isActive}
+					style:background={gradientCss(variant)}
+					onclick={() => theme.setVariant(variant)}
+					aria-label={def.label}
+					aria-pressed={isActive}
+				>
+					<!-- Active checkmark -->
+					{#if isActive}
+						<span class="active-check">
+							<Check size={12} weight="bold" />
+						</span>
+					{/if}
+
+					<!-- Theme name overlay -->
+					<span class="theme-label">{def.label}</span>
+				</button>
+			{/each}
+		</div>
+	</section>
+
+	<!-- ── Wallpaper section ──────────────────────────────────────── -->
+	<section class="wallpaper-section">
+		<h2 class="section-heading">Hintergrund</h2>
+		<WallpaperPicker />
+	</section>
 </div>
 
 <style>
@@ -31,18 +108,172 @@
 		padding: 0.75rem;
 		height: 100%;
 		overflow-y: auto;
+		display: flex;
+		flex-direction: column;
+		gap: 1.25rem;
 	}
 
+	.section-heading {
+		font-size: 0.6875rem;
+		font-weight: 600;
+		color: hsl(var(--color-muted-foreground));
+		text-transform: uppercase;
+		letter-spacing: 0.06em;
+		margin: 0 0 0.625rem 0;
+	}
+
+	/* ── Mode selector ─────────────────────────────────────────── */
+	.mode-row {
+		display: flex;
+		gap: 0.25rem;
+		padding: 0.25rem;
+		background: hsl(var(--color-muted) / 0.3);
+		border-radius: 0.625rem;
+	}
+
+	.mode-btn {
+		flex: 1;
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		gap: 0.375rem;
+		padding: 0.5rem 0.625rem;
+		border: none;
+		background: transparent;
+		border-radius: 0.5rem;
+		font-size: 0.8125rem;
+		font-weight: 500;
+		color: hsl(var(--color-muted-foreground));
+		cursor: pointer;
+		transition:
+			background 0.15s,
+			color 0.15s,
+			box-shadow 0.15s;
+	}
+
+	.mode-btn:hover {
+		color: hsl(var(--color-foreground));
+	}
+
+	.mode-btn.active {
+		background: hsl(var(--color-primary));
+		color: hsl(var(--color-primary-foreground, 0 0% 100%));
+		box-shadow: 0 1px 3px hsl(0 0% 0% / 0.12);
+	}
+
+	.mode-btn.active:hover {
+		color: hsl(var(--color-primary-foreground, 0 0% 100%));
+	}
+
+	/* ── Theme cards ───────────────────────────────────────────── */
+	.themes-grid {
+		display: grid;
+		grid-template-columns: repeat(2, minmax(0, 1fr));
+		gap: 0.625rem;
+	}
+
+	.theme-card {
+		position: relative;
+		aspect-ratio: 16 / 10;
+		border: 1px solid hsl(var(--color-border));
+		border-radius: 0.75rem;
+		cursor: pointer;
+		overflow: hidden;
+		padding: 0;
+		transition:
+			transform 0.18s ease,
+			box-shadow 0.18s ease,
+			border-color 0.15s;
+	}
+
+	.theme-card:hover {
+		transform: translateY(-1px);
+		box-shadow: 0 4px 12px hsl(0 0% 0% / 0.12);
+	}
+
+	.theme-card.active {
+		border-color: hsl(var(--color-primary));
+		box-shadow:
+			0 0 0 2px hsl(var(--color-primary) / 0.35),
+			0 4px 12px hsl(0 0% 0% / 0.12);
+	}
+
+	/* Dark overlay at the bottom for label readability */
+	.theme-card::after {
+		content: '';
+		position: absolute;
+		inset: 0;
+		background: linear-gradient(180deg, transparent 50%, hsl(0 0% 0% / 0.35) 100%);
+		pointer-events: none;
+	}
+
+	.active-check {
+		position: absolute;
+		top: 0.5rem;
+		right: 0.5rem;
+		z-index: 2;
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		width: 20px;
+		height: 20px;
+		border-radius: 50%;
+		background: hsl(0 0% 100%);
+		color: hsl(var(--color-primary));
+		box-shadow: 0 1px 4px hsl(0 0% 0% / 0.2);
+	}
+
+	.theme-label {
+		position: absolute;
+		left: 0.625rem;
+		bottom: 0.5rem;
+		z-index: 1;
+		font-size: 0.875rem;
+		font-weight: 700;
+		color: hsl(0 0% 100%);
+		text-shadow: 0 1px 3px hsl(0 0% 0% / 0.5);
+		letter-spacing: -0.01em;
+	}
+
+	/* ── Wallpaper section ─────────────────────────────────────── */
 	.wallpaper-section {
-		margin-top: 2rem;
-		padding-top: 2rem;
+		padding-top: 1rem;
 		border-top: 1px solid hsl(var(--color-border));
 	}
 
-	.wallpaper-heading {
-		font-size: 0.875rem;
-		font-weight: 500;
+	/* Force all WallpaperPicker grids to 2 columns in this panel context
+	   (defaults are 4 and 3 which cram tiles in a narrow panel). */
+	.wallpaper-section :global(.grid.grid-cols-4),
+	.wallpaper-section :global(.grid.grid-cols-3) {
+		grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
+		gap: 0.625rem !important;
+	}
+
+	/* WallpaperPicker pill-group buttons (scope toggle + Farben/Bilder/
+	   Upload tabs) — restyle to match the mode selector above so active
+	   state reads clearly against the panel background. */
+	.wallpaper-section :global(.flex.rounded-lg.bg-muted) {
+		background: hsl(var(--color-muted) / 0.3);
+	}
+
+	.wallpaper-section :global(.flex.rounded-lg.bg-muted > button) {
 		color: hsl(var(--color-muted-foreground));
-		margin-bottom: 1rem;
+		transition:
+			background 0.15s,
+			color 0.15s,
+			box-shadow 0.15s;
+	}
+
+	.wallpaper-section :global(.flex.rounded-lg.bg-muted > button:hover) {
+		color: hsl(var(--color-foreground));
+	}
+
+	/* Active pill-group button — primary fill with white text, matching
+	   the mode selector. Targets the button that carries .bg-surface
+	   (applied via `class:bg-surface={activeTab === tab.id}`). */
+	.wallpaper-section :global(.flex.rounded-lg.bg-muted > button.bg-surface) {
+		background: hsl(var(--color-primary)) !important;
+		color: hsl(var(--color-primary-foreground, 0 0% 100%)) !important;
+		box-shadow: 0 1px 3px hsl(0 0% 0% / 0.12) !important;
 	}
 </style>