feat(client): redesign frontend with TailwindCSS v4

Replace inline styles with TailwindCSS, implementing a cohesive Japanese-inspired
design system with custom colors (cream, teal primary), typography (Fraunces,
DM Sans), and animations. Update all pages and components with consistent styling,
improve accessibility by adding aria-hidden to decorative SVGs, and configure
Biome for Tailwind CSS syntax support.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 178 insertions, 74 deletions

diff --git a/src/client/pages/HomePage.tsx b/src/client/pages/HomePage.tsx
index 783e623..fcae971 100644
--- a/src/client/pages/HomePage.tsx
+++ b/src/client/pages/HomePage.tsx
@@ -62,122 +62,226 @@ export function HomePage() {
 	}, [fetchDecks]);
 
 	return (
-		<div>
-			<header
-				style={{
-					display: "flex",
-					justifyContent: "space-between",
-					alignItems: "center",
-					marginBottom: "1rem",
-				}}
-			>
-				<h1>Kioku</h1>
-				<div style={{ display: "flex", alignItems: "center", gap: "1rem" }}>
-					<SyncStatusIndicator />
-					<SyncButton />
-					<button type="button" onClick={logout}>
-						Logout
-					</button>
+		<div className="min-h-screen bg-cream">
+			{/* Header */}
+			<header className="bg-white border-b border-border/50 sticky top-0 z-10">
+				<div className="max-w-4xl mx-auto px-4 py-4 flex items-center justify-between">
+					<h1 className="font-display text-2xl font-semibold text-ink">
+						Kioku
+					</h1>
+					<div className="flex items-center gap-3">
+						<SyncStatusIndicator />
+						<SyncButton />
+						<button
+							type="button"
+							onClick={logout}
+							className="text-sm text-muted hover:text-slate transition-colors px-3 py-1.5 rounded-lg hover:bg-ivory"
+						>
+							Logout
+						</button>
+					</div>
 				</div>
 			</header>
 
-			<main>
-				<div
-					style={{
-						display: "flex",
-						justifyContent: "space-between",
-						alignItems: "center",
-						marginBottom: "1rem",
-					}}
-				>
-					<h2 style={{ margin: 0 }}>Your Decks</h2>
-					<button type="button" onClick={() => setIsCreateModalOpen(true)}>
-						Create Deck
+			{/* Main Content */}
+			<main className="max-w-4xl mx-auto px-4 py-8">
+				{/* Section Header */}
+				<div className="flex items-center justify-between mb-6">
+					<h2 className="font-display text-xl font-medium text-slate">
+						Your Decks
+					</h2>
+					<button
+						type="button"
+						onClick={() => setIsCreateModalOpen(true)}
+						className="inline-flex items-center gap-2 bg-primary hover:bg-primary-dark text-white font-medium py-2 px-4 rounded-lg transition-all duration-200 active:scale-[0.98] shadow-sm hover:shadow-md"
+					>
+						<svg
+							className="w-5 h-5"
+							fill="none"
+							stroke="currentColor"
+							viewBox="0 0 24 24"
+							aria-hidden="true"
+						>
+							<path
+								strokeLinecap="round"
+								strokeLinejoin="round"
+								strokeWidth={2}
+								d="M12 4v16m8-8H4"
+							/>
+						</svg>
+						New Deck
 					</button>
 				</div>
 
-				{isLoading && <p>Loading decks...</p>}
+				{/* Loading State */}
+				{isLoading && (
+					<div className="flex items-center justify-center py-12">
+						<svg
+							className="animate-spin h-8 w-8 text-primary"
+							viewBox="0 0 24 24"
+							aria-hidden="true"
+						>
+							<circle
+								className="opacity-25"
+								cx="12"
+								cy="12"
+								r="10"
+								stroke="currentColor"
+								strokeWidth="4"
+								fill="none"
+							/>
+							<path
+								className="opacity-75"
+								fill="currentColor"
+								d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z"
+							/>
+						</svg>
+					</div>
+				)}
 
+				{/* Error State */}
 				{error && (
-					<div role="alert" style={{ color: "red" }}>
-						{error}
+					<div
+						role="alert"
+						className="bg-error/5 border border-error/20 rounded-xl p-4 flex items-center justify-between"
+					>
+						<span className="text-error">{error}</span>
 						<button
 							type="button"
 							onClick={fetchDecks}
-							style={{ marginLeft: "0.5rem" }}
+							className="text-error hover:text-error/80 font-medium text-sm"
 						>
 							Retry
 						</button>
 					</div>
 				)}
 
+				{/* Empty State */}
 				{!isLoading && !error && decks.length === 0 && (
-					<div>
-						<p>You don't have any decks yet.</p>
-						<p>Create your first deck to start learning!</p>
+					<div className="text-center py-16 animate-fade-in">
+						<div className="w-16 h-16 mx-auto mb-4 bg-ivory rounded-2xl flex items-center justify-center">
+							<svg
+								className="w-8 h-8 text-muted"
+								fill="none"
+								stroke="currentColor"
+								viewBox="0 0 24 24"
+								aria-hidden="true"
+							>
+								<path
+									strokeLinecap="round"
+									strokeLinejoin="round"
+									strokeWidth={1.5}
+									d="M19 11H5m14 0a2 2 0 012 2v6a2 2 0 01-2 2H5a2 2 0 01-2-2v-6a2 2 0 012-2m14 0V9a2 2 0 00-2-2M5 11V9a2 2 0 012-2m0 0V5a2 2 0 012-2h6a2 2 0 012 2v2M7 7h10"
+								/>
+							</svg>
+						</div>
+						<h3 className="font-display text-lg font-medium text-slate mb-2">
+							No decks yet
+						</h3>
+						<p className="text-muted text-sm mb-6">
+							Create your first deck to start learning
+						</p>
+						<button
+							type="button"
+							onClick={() => setIsCreateModalOpen(true)}
+							className="inline-flex items-center gap-2 bg-primary hover:bg-primary-dark text-white font-medium py-2.5 px-5 rounded-lg transition-all duration-200"
+						>
+							<svg
+								className="w-5 h-5"
+								fill="none"
+								stroke="currentColor"
+								viewBox="0 0 24 24"
+								aria-hidden="true"
+							>
+								<path
+									strokeLinecap="round"
+									strokeLinejoin="round"
+									strokeWidth={2}
+									d="M12 4v16m8-8H4"
+								/>
+							</svg>
+							Create Your First Deck
+						</button>
 					</div>
 				)}
 
+				{/* Deck List */}
 				{!isLoading && !error && decks.length > 0 && (
-					<ul style={{ listStyle: "none", padding: 0 }}>
-						{decks.map((deck) => (
-							<li
+					<div className="space-y-3 animate-fade-in">
+						{decks.map((deck, index) => (
+							<div
 								key={deck.id}
-								style={{
-									border: "1px solid #ccc",
-									padding: "1rem",
-									marginBottom: "0.5rem",
-									borderRadius: "4px",
-								}}
+								className="bg-white rounded-xl border border-border/50 p-5 shadow-card hover:shadow-md transition-all duration-200 group"
+								style={{ animationDelay: `${index * 50}ms` }}
 							>
-								<div
-									style={{
-										display: "flex",
-										justifyContent: "space-between",
-										alignItems: "flex-start",
-									}}
-								>
-									<div>
-										<h3 style={{ margin: 0 }}>
-											<Link
-												href={`/decks/${deck.id}`}
-												style={{ textDecoration: "none", color: "inherit" }}
-											>
+								<div className="flex items-start justify-between gap-4">
+									<div className="flex-1 min-w-0">
+										<Link
+											href={`/decks/${deck.id}`}
+											className="block group-hover:text-primary transition-colors"
+										>
+											<h3 className="font-display text-lg font-medium text-slate truncate">
 												{deck.name}
-											</Link>
-										</h3>
+											</h3>
+										</Link>
 										{deck.description && (
-											<p style={{ margin: "0.5rem 0 0 0", color: "#666" }}>
+											<p className="text-muted text-sm mt-1 line-clamp-2">
 												{deck.description}
 											</p>
 										)}
 									</div>
-									<div style={{ display: "flex", gap: "0.5rem" }}>
-										<button type="button" onClick={() => setEditingDeck(deck)}>
-											Edit
+									<div className="flex items-center gap-2 shrink-0">
+										<button
+											type="button"
+											onClick={() => setEditingDeck(deck)}
+											className="p-2 text-muted hover:text-slate hover:bg-ivory rounded-lg transition-colors"
+											title="Edit deck"
+										>
+											<svg
+												className="w-4 h-4"
+												fill="none"
+												stroke="currentColor"
+												viewBox="0 0 24 24"
+												aria-hidden="true"
+											>
+												<path
+													strokeLinecap="round"
+													strokeLinejoin="round"
+													strokeWidth={2}
+													d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"
+												/>
+											</svg>
 										</button>
 										<button
 											type="button"
 											onClick={() => setDeletingDeck(deck)}
-											style={{
-												backgroundColor: "#dc3545",
-												color: "white",
-												border: "none",
-												padding: "0.25rem 0.5rem",
-												borderRadius: "4px",
-												cursor: "pointer",
-											}}
+											className="p-2 text-muted hover:text-error hover:bg-error/5 rounded-lg transition-colors"
+											title="Delete deck"
 										>
-											Delete
+											<svg
+												className="w-4 h-4"
+												fill="none"
+												stroke="currentColor"
+												viewBox="0 0 24 24"
+												aria-hidden="true"
+											>
+												<path
+													strokeLinecap="round"
+													strokeLinejoin="round"
+													strokeWidth={2}
+													d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16"
+												/>
+											</svg>
 										</button>
 									</div>
 								</div>
-							</li>
+							</div>
 						))}
-					</ul>
+					</div>
 				)}
 			</main>
 
+			{/* Modals */}
 			<CreateDeckModal
 				isOpen={isCreateModalOpen}
 				onClose={() => setIsCreateModalOpen(false)}