/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f7;
}

/* 头部样式 */
.header {
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 100;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 600;
}

.nav a {
    color: #333;
    text-decoration: none;
    margin-left: 2rem;
    transition: color 0.3s;
}

.nav a:hover, .nav a.active {
    color: #007AFF;
}

/* 主要内容区域 */
.main-content {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 80px 20px;
}

.container {
    background-color: white;
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    text-align: center;
}

/* 计时器显示 */
.timer {
    font-size: 4rem;
    font-weight: 300;
    margin-bottom: 2rem;
    font-variant-numeric: tabular-nums;
}

/* 按钮样式 */
.buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn {
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
}

#startBtn {
    background-color: #007AFF;
    color: white;
}

#pauseBtn {
    background-color: #FF9500;
    color: white;
}

#resetBtn {
    background-color: #FF3B30;
    color: white;
}

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

/* 页脚样式 */
.footer {
    background-color: #fff;
    padding: 2rem 0;
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links a {
    color: #666;
    text-decoration: none;
    margin-left: 1.5rem;
    transition: color 0.3s;
}

.footer-links a:hover {
    color: #007AFF;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .timer {
        font-size: 3rem;
    }
    
    .buttons {
        flex-direction: column;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }
    
    .footer-links a {
        margin: 0 0.75rem;
    }
}