* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: system-ui, sans-serif; background: #f5f5f5; display: flex; justify-content: center; padding: 40px 16px; }
.container { width: 100%; max-width: 500px; }
h1 { margin-bottom: 20px; color: #333; }
.add-form { display: flex; gap: 8px; margin-bottom: 24px; }
.add-form input { flex: 1; padding: 10px; border: 1px solid #ddd; border-radius: 6px; font-size: 16px; }
.add-form button { padding: 10px 20px; background: #d94a4a; color: #fff; border: none; border-radius: 6px; cursor: pointer; font-size: 16px; }
.add-form button:hover { background: #357abd; }
.todo { display: flex; align-items: center; gap: 10px; background: #fff; padding: 12px 16px; border-radius: 6px; margin-bottom: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.08); }
.todo.done span { text-decoration: line-through; color: #999; }
.todo span { flex: 1; }
.todo button { background: none; border: none; cursor: pointer; font-size: 18px; padding: 4px 8px; }
.empty { color: #999; text-align: center; margin-top: 40px; }