/* ==================== 全局样式 ==================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

/* ==================== 导航栏 ==================== */

.navbar {
    background: #fff;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: #2563eb;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 32px;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-links a {
    text-decoration: none;
    color: #666;
    font-size: 15px;
    transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: #2563eb;
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
    display: none;
    width: 40px;
    height: 40px;
    background: none;
    border: none;
    cursor: pointer;
    position: relative;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: #333;
    position: absolute;
    left: 8px;
    transition: all 0.3s;
}

.mobile-menu-btn span:nth-child(1) {
    top: 12px;
}

.mobile-menu-btn span:nth-child(2) {
    top: 19px;
}

.mobile-menu-btn span:nth-child(3) {
    top: 26px;
}

.mobile-menu-btn.active span:nth-child(1) {
    top: 19px;
    transform: rotate(45deg);
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    top: 19px;
    transform: rotate(-45deg);
}

/* ==================== 内容区域 ==================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

.section {
    background: #fff;
    padding: 40px;
    margin-bottom: 32px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.section h2 {
    font-size: 28px;
    margin-bottom: 20px;
    color: #1a1a1a;
}

.section h3 {
    font-size: 24px;
    margin-bottom: 16px;
    color: #1a1a1a;
}

.section p {
    margin-bottom: 12px;
    color: #666;
}

/* ==================== 功能卡片 ==================== */

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 32px;
}

.feature-card {
    background: #fff;
    padding: 28px;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

.feature-icon {
    font-size: 40px;
    margin-bottom: 16px;
}

.feature-card h4 {
    font-size: 18px;
    margin-bottom: 12px;
    color: #1a1a1a;
}

.feature-card p {
    font-size: 14px;
    color: #666;
    line-height: 1.8;
}

/* ==================== 按钮 ==================== */

.btn {
    display: inline-block;
    padding: 12px 28px;
    background: #2563eb;
    color: #fff;
    text-decoration: none;
    border-radius: 8px;
    font-size: 15px;
    transition: all 0.3s;
}

.btn:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: #fff;
    border: 2px solid rgba(255,255,255,0.5);
}

.btn-secondary:hover {
    background: rgba(255,255,255,0.15);
    transform: translateY(-2px);
}

/* ==================== Footer ==================== */

.footer {
    background: #1a1a1a;
    color: #999;
    padding: 40px 20px;
    text-align: center;
}

.footer a {
    color: #fff;
    text-decoration: none;
}

.footer a:hover {
    color: #2563eb;
}

/* ==================== 响应式设计 ==================== */

@media (max-width: 1024px) {
    .container {
        padding: 30px 16px;
    }
    
    .section {
        padding: 30px;
    }
    
    .features {
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    }
}

@media (max-width: 768px) {
    /* 显示移动端菜单按钮 */
    .mobile-menu-btn {
        display: block;
    }
    
    /* 导航菜单 */
    .nav-links {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: #fff;
        flex-direction: column;
        gap: 0;
        padding: 0;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        transform: translateY(-100%);
        opacity: 0;
        transition: all 0.3s ease;
        z-index: 999;
    }
    
    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
    }
    
    .nav-links li {
        border-bottom: 1px solid #f3f4f6;
    }
    
    .nav-links a {
        display: block;
        padding: 16px 20px;
        font-size: 16px;
    }
    
    /* 容器 */
    .container {
        padding: 30px 16px;
    }
    
    .section {
        padding: 24px 20px;
        margin-bottom: 24px;
    }
    
    .section h2 {
        font-size: 24px;
    }
    
    .section h3 {
        font-size: 20px;
    }
    
    /* 功能卡片 */
    .features {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .feature-card {
        padding: 20px;
    }
    
    .feature-card h4 {
        font-size: 16px;
    }
    
    /* Footer */
    .footer {
        padding: 30px 20px;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 20px;
    }
    
    .section h2 {
        font-size: 22px;
    }
    
    .section h3 {
        font-size: 18px;
    }
}