/* 平板设备 (768px - 1024px) */
@media (max-width: 1024px) {
    .container {
        padding: 0 15px;
    }
    
    nav {
        padding: 0 15px;
    }
    
    .nav-links {
        gap: 1.5rem;
    }
    
    section {
        padding: 4rem 0;
    }
    
    .grid-2 {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .grid-3 {
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
        gap: 1.5rem;
    }
    
    .hero {
        padding: 7rem 0 3rem;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
}

/* 移动设备 (768px 以下) */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .container {
        padding: 0 10px;
    }
    
    /* 移动端导航 */
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(26, 86, 219, 0.98);
        flex-direction: column;
        padding: 1rem;
        gap: 0;
        backdrop-filter: blur(20px);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-links a {
        padding: 1rem;
        border-bottom: 1px solid rgba(255,255,255,0.1);
        width: 100%;
        text-align: center;
    }
    
    .nav-links a:last-child {
        border-bottom: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    /* 移动端布局调整 */
    section {
        padding: 3rem 0;
    }
    
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .hero {
        padding: 6rem 0 2rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .card {
        padding: 1.5rem;
    }
    
    .card-feature {
        padding: 2rem 1.5rem;
    }
    
    /* 按钮组垂直排列 */
    .button-group {
        flex-direction: column;
        align-items: center;
    }
    
    .button-group .cta-button,
    .button-group .secondary-button {
        width: 100%;
        max-width: 300px;
    }
    
    /* 页脚调整 */
    .footer-links {
        flex-direction: column;
        gap: 1rem;
    }
}

/* 小屏移动设备 (480px 以下) */
@media (max-width: 480px) {
    html {
        font-size: 13px;
    }
    
    .container {
        padding: 0 5px;
    }
    
    nav {
        padding: 0 10px;
    }
    
    section {
        padding: 2rem 0;
    }
    
    .hero {
        padding: 5rem 0 2rem;
    }
    
    .card {
        padding: 1rem;
    }
    
    .cta-button,
    .secondary-button {
        padding: 12px 20px;
        font-size: 0.9rem;
    }
}

/* 桌面大屏 (1200px 以上) */
@media (min-width: 1200px) {
    .container {
        max-width: var(--desktop-width);
    }
}

/* 超大屏 (1400px 以上) */
@media (min-width: 1400px) {
    .container {
        max-width: 1320px;
    }
}

/* 打印样式 */
@media print {
    .cta-button,
    .secondary-button,
    .mobile-menu-btn {
        display: none !important;
    }
    
    header {
        position: static;
    }
    
    main {
        margin-top: 0;
    }
}