/* 移动端适配 */

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .main-nav {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--bg-secondary);
        flex-direction: column;
        padding: 20px;
        gap: 0;
        border-bottom: 1px solid var(--border);
        transform: translateY(-150%);
        transition: transform 0.3s;
        box-shadow: var(--shadow-lg);
        display: flex;
    }
    
    .main-nav.open {
        transform: translateY(0);
    }
    
    .nav-link {
        padding: 12px 0;
        border-bottom: 1px solid var(--border);
    }
    
    .nav-link:last-child {
        border-bottom: none;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
        letter-spacing: 2px;
    }
    
    .stats-bar {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    .stat-box {
        padding: 16px;
    }
    
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .about-image {
        order: -1;
        transform: none;
    }
    
    .about-image:hover {
        transform: none;
    }
    
    .timeline::before {
        left: 20px;
    }
    
    .timeline-item,
    .timeline-item:nth-child(even) {
        padding-left: 60px;
        padding-right: 0;
        justify-content: flex-start;
    }
    
    .timeline-content,
    .timeline-item:nth-child(even) .timeline-content {
        margin-left: 0;
        margin-right: 0;
        max-width: 100%;
    }
    
    .timeline-date {
        left: 20px;
        transform: translateX(-50%);
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
        text-align: center;
    }
    
    .footer-links h4::after {
        left: 50%;
        transform: translateX(-50%);
    }
    
    .slider-track {
        height: 250px;
    }
    
    .slider-arrow {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
    
    .slider-prev { left: 10px; }
    .slider-next { right: 10px; }
    
    .friends-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
        width: 100%;
        padding: 0 20px;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
}