/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

/* 主题变量 */
:root {
    --background-color: #f5f5f7;
    --card-color: #ffffff;
    --primary-color: #0a84ff;
    --secondary-color: #8e8e93;
    --danger-color: #ff6b8b;
    --text-color: #1d1d1f;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --border-radius: 16px;
}

/* 暗黑模式 */
@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #1c1c1e;
        --card-color: #2c2c2e;
        --text-color: #ffffff;
        --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    }
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    width: 100%;
    max-width: 500px;
    padding: 20px;
}

.timer-card {
    background-color: var(--card-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 40px;
    text-align: center;
}

h1 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 30px;
    background: linear-gradient(45deg, #0a84ff, #64d2ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.timer-display {
    font-size: 3.5rem;
    font-weight: 300;
    margin-bottom: 40px;
    letter-spacing: 2px;
}

.colon {
    opacity: 0.8;
    animation: blink 1s infinite;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.controls {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.btn {
    padding: 12px 24px;
    border-radius: 12px;
    border: none;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 100px;
}

.btn:active {
    transform: scale(0.97);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn.primary {
    background: linear-gradient(135deg, #0a84ff, #00d2ff);
    color: white;
    box-shadow: 0 4px 10px rgba(10, 132, 255, 0.3);
}

.btn.primary:hover:not(:disabled) {
    box-shadow: 0 6px 15px rgba(10, 132, 255, 0.4);
    transform: translateY(-2px);
}

.btn.secondary {
    background: linear-gradient(135deg, #8e8e93, #aeaeb2);
    color: white;
    box-shadow: 0 4px 10px rgba(142, 142, 147, 0.3);
}

.btn.secondary:hover:not(:disabled) {
    box-shadow: 0 6px 15px rgba(142, 142, 147, 0.4);
    transform: translateY(-2px);
}

.btn.danger {
    background: linear-gradient(135deg, #ff6b8b, #ff9db0);
    color: white;
    box-shadow: 0 4px 10px rgba(255, 107, 139, 0.3);
}

.btn.danger:hover:not(:disabled) {
    box-shadow: 0 6px 15px rgba(255, 107, 139, 0.4);
    transform: translateY(-2px);
}

/* 响应式设计 */
@media (max-width: 576px) {
    .timer-card {
        padding: 30px 20px;
    }
    
    .timer-display {
        font-size: 2.8rem;
    }
    
    .controls {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
}