/* ========================================
   Beijing Dayue Shengqi Technology Co., Ltd.
   Responsive Stylesheet
   ======================================== */

/* Extra Large Devices (1400px and up) */
@media (min-width: 1400px) {
    .container {
        max-width: 1320px;
    }
    
    .hero-title {
        font-size: 4.5rem;
    }
    
    .section-title {
        font-size: 3rem;
    }
}

/* Large Devices (1200px - 1399px) */
@media (min-width: 1200px) and (max-width: 1399px) {
    .container {
        max-width: 1140px;
    }
}

/* Medium Large Devices (992px - 1199px) */
@media (min-width: 992px) and (max-width: 1199px) {
    .container {
        max-width: 960px;
    }
    
    h1 { font-size: 2.75rem; }
    h2 { font-size: 2.25rem; }
    h3 { font-size: 1.75rem; }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .team-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .news-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
    
    .app-showcase {
        gap: 3rem;
    }
    
    .contact-grid {
        gap: 3rem;
    }
}

/* Tablet Devices (768px - 991px) */
@media (min-width: 768px) and (max-width: 991px) {
    .container {
        max-width: 720px;
    }
    
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.5rem; }
    
    .header .container {
        height: 70px;
    }
    
    .nav-menu {
        gap: 1.5rem;
    }
    
    .hero {
        min-height: auto;
        padding: 7rem 0 4rem;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .section {
        padding: 5rem 0;
    }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .app-showcase {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .app-preview {
        order: -1;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .stat-number {
        font-size: 2.5rem;
    }
    
    .team-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
    
    .footer-brand {
        grid-column: span 2;
    }
    
    .ad-platforms-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .ad-types-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .page-header {
        padding: 7rem 0 3rem;
    }
    
    .page-title {
        font-size: 2.5rem;
    }
}

/* Mobile Devices (576px - 767px) */
@media (min-width: 576px) and (max-width: 767px) {
    .container {
        max-width: 540px;
    }
    
    h1 { font-size: 2.25rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.375rem; }
    h4 { font-size: 1.125rem; }
    
    .header .container {
        height: 60px;
    }
    
    .logo {
        font-size: 1.25rem;
    }
    
    .logo svg {
        width: 32px;
        height: 32px;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-menu {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: #ffffff;
        flex-direction: column;
        padding: 1.5rem;
        gap: 1rem;
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
        border-top: 1px solid var(--border-color);
    }
    
    .nav-menu.active {
        display: flex;
    }
    
    .nav-menu a {
        padding: 0.75rem 0;
        border-bottom: 1px solid var(--border-color);
    }
    
    .hero {
        min-height: auto;
        padding: 6rem 0 3rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-buttons .btn {
        width: 100%;
        justify-content: center;
    }
    
    .hero-badge {
        font-size: 0.75rem;
        padding: 0.375rem 0.75rem;
    }
    
    .section {
        padding: 4rem 0;
    }
    
    .section-header {
        margin-bottom: 2.5rem;
    }
    
    .section-badge {
        font-size: 0.75rem;
        padding: 0.375rem 0.75rem;
    }
    
    .section-description {
        font-size: 1rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .feature-card {
        padding: 1.5rem;
    }
    
    .feature-icon {
        width: 48px;
        height: 48px;
    }
    
    .feature-icon svg {
        width: 24px;
        height: 24px;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .service-image {
        height: 160px;
    }
    
    .service-image svg {
        width: 60px;
        height: 60px;
    }
    
    .service-content {
        padding: 1.25rem;
    }
    
    .app-showcase {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .app-preview {
        order: -1;
    }
    
    .phone-mockup {
        max-width: 250px;
    }
    
    .phone-screen {
        height: 400px;
        font-size: 1rem;
    }
    
    .app-buttons {
        flex-direction: column;
    }
    
    .store-badge {
        width: 100%;
        justify-content: center;
        padding: 0.625rem 1.25rem;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }
    
    .stat-item {
        padding: 0.75rem;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .stat-label {
        font-size: 0.875rem;
    }
    
    .team-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .team-avatar {
        width: 100px;
        height: 100px;
        font-size: 2rem;
    }
    
    .timeline::before {
        left: 15px;
    }
    
    .timeline-item {
        padding-left: 40px;
        padding-right: 0;
        justify-content: flex-start;
    }
    
    .timeline-item:nth-child(odd),
    .timeline-item:nth-child(even) {
        padding-left: 40px;
        padding-right: 0;
    }
    
    .timeline-dot {
        left: 15px;
        width: 12px;
        height: 12px;
    }
    
    .timeline-content {
        padding: 1rem;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .news-image {
        height: 160px;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .contact-icon {
        width: 40px;
        height: 40px;
    }
    
    .contact-icon svg {
        width: 20px;
        height: 20px;
    }
    
    .contact-form {
        padding: 1.5rem;
    }
    
    .form-group {
        margin-bottom: 1rem;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .footer-brand {
        grid-column: span 1;
        max-width: 100%;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .footer-legal {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .ad-platforms-grid {
        grid-template-columns: 1fr;
    }
    
    .ad-types-grid {
        grid-template-columns: 1fr;
    }
    
    .page-header {
        padding: 6rem 0 2.5rem;
    }
    
    .page-title {
        font-size: 2rem;
    }
    
    .page-subtitle {
        font-size: 1rem;
    }
    
    .breadcrumb {
        font-size: 0.75rem;
    }
    
    .legal-content {
        padding: 3rem 0;
    }
    
    .legal-section {
        margin-bottom: 1.5rem;
    }
    
    .legal-title {
        font-size: 1.25rem;
    }
}

/* Extra Small Devices (up to 575px) */
@media (max-width: 575px) {
    .container {
        padding: 0 1rem;
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.25rem; }
    h4 { font-size: 1rem; }
    
    .header .container {
        height: 56px;
    }
    
    .logo {
        font-size: 1.125rem;
    }
    
    .logo svg {
        width: 28px;
        height: 28px;
    }
    
    .mobile-menu-btn svg {
        width: 24px;
        height: 24px;
    }
    
    .nav-menu {
        top: 56px;
    }
    
    .hero {
        min-height: auto;
        padding: 5rem 0 2.5rem;
    }
    
    .hero-content {
        text-align: center;
    }
    
    .hero-badge {
        font-size: 0.625rem;
        padding: 0.25rem 0.5rem;
        margin-bottom: 1rem;
    }
    
    .hero-title {
        font-size: 2rem;
        margin-bottom: 1rem;
    }
    
    .hero-subtitle {
        font-size: 0.875rem;
        margin-bottom: 1.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.875rem;
    }
    
    .btn-lg {
        padding: 0.875rem 2rem;
        font-size: 1rem;
    }
    
    .section {
        padding: 3rem 0;
    }
    
    .section-header {
        margin-bottom: 2rem;
    }
    
    .section-badge {
        font-size: 0.625rem;
        padding: 0.25rem 0.5rem;
    }
    
    .section-description {
        font-size: 0.875rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .feature-card {
        padding: 1.25rem;
    }
    
    .feature-icon {
        width: 40px;
        height: 40px;
        margin-bottom: 1rem;
    }
    
    .feature-icon svg {
        width: 20px;
        height: 20px;
    }
    
    .feature-title {
        font-size: 1rem;
    }
    
    .feature-description {
        font-size: 0.875rem;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .service-image {
        height: 140px;
    }
    
    .service-image svg {
        width: 48px;
        height: 48px;
    }
    
    .service-content {
        padding: 1rem;
    }
    
    .service-title {
        font-size: 1rem;
    }
    
    .service-description {
        font-size: 0.875rem;
    }
    
    .app-showcase {
        gap: 1.5rem;
    }
    
    .app-content h3 {
        font-size: 1.5rem;
    }
    
    .app-features li {
        font-size: 0.875rem;
    }
    
    .app-buttons {
        gap: 0.75rem;
    }
    
    .store-badge {
        flex: 1;
        padding: 0.5rem 1rem;
    }
    
    .store-badge svg {
        width: 20px;
        height: 20px;
    }
    
    .store-badge-text span {
        font-size: 0.625rem;
    }
    
    .store-badge-text strong {
        font-size: 0.875rem;
    }
    
    .phone-mockup {
        max-width: 220px;
        border-radius: 30px;
        padding: 8px;
    }
    
    .phone-screen {
        height: 350px;
        border-radius: 24px;
        font-size: 0.875rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .stat-number {
        font-size: 1.75rem;
    }
    
    .stat-label {
        font-size: 0.75rem;
    }
    
    .team-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .team-card {
        padding: 1.5rem;
    }
    
    .team-avatar {
        width: 80px;
        height: 80px;
        font-size: 1.5rem;
    }
    
    .team-name {
        font-size: 1rem;
    }
    
    .team-role {
        font-size: 0.875rem;
    }
    
    .team-bio {
        font-size: 0.75rem;
    }
    
    .timeline::before {
        left: 10px;
    }
    
    .timeline-item {
        padding-left: 30px;
    }
    
    .timeline-item:nth-child(odd),
    .timeline-item:nth-child(even) {
        padding-left: 30px;
        padding-right: 0;
    }
    
    .timeline-dot {
        left: 10px;
        width: 10px;
        height: 10px;
        border-width: 2px;
    }
    
    .timeline-content {
        padding: 0.875rem;
    }
    
    .timeline-year {
        font-size: 0.875rem;
    }
    
    .timeline-title {
        font-size: 1rem;
    }
    
    .timeline-description {
        font-size: 0.75rem;
    }
    
    .news-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .news-image {
        height: 140px;
    }
    
    .news-content {
        padding: 1rem;
    }
    
    .news-meta {
        font-size: 0.75rem;
    }
    
    .news-title {
        font-size: 1rem;
    }
    
    .news-excerpt {
        font-size: 0.75rem;
    }
    
    .contact-grid {
        gap: 1.5rem;
    }
    
    .contact-info h3 {
        font-size: 1.25rem;
    }
    
    .contact-item {
        margin-bottom: 1rem;
    }
    
    .contact-icon {
        width: 36px;
        height: 36px;
    }
    
    .contact-icon svg {
        width: 18px;
        height: 18px;
    }
    
    .contact-label {
        font-size: 0.75rem;
    }
    
    .contact-value {
        font-size: 0.875rem;
    }
    
    .contact-form {
        padding: 1rem;
    }
    
    .form-label {
        font-size: 0.875rem;
    }
    
    .form-input,
    .form-textarea,
    .form-select {
        padding: 0.625rem 0.75rem;
        font-size: 0.875rem;
    }
    
    .form-textarea {
        min-height: 100px;
    }
    
    .footer {
        padding-top: 3rem;
    }
    
    .footer-grid {
        gap: 1.5rem;
        padding-bottom: 2rem;
    }
    
    .footer-logo {
        font-size: 1rem;
    }
    
    .footer-logo svg {
        width: 24px;
        height: 24px;
    }
    
    .footer-description {
        font-size: 0.875rem;
    }
    
    .footer-title {
        font-size: 1rem;
        margin-bottom: 1rem;
    }
    
    .footer-links {
        font-size: 0.875rem;
    }
    
    .footer-links li {
        margin-bottom: 0.5rem;
    }
    
    .social-link {
        width: 32px;
        height: 32px;
    }
    
    .social-link svg {
        width: 16px;
        height: 16px;
    }
    
    .footer-bottom {
        padding: 1rem 0;
        font-size: 0.75rem;
    }
    
    .ad-platforms-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .ad-platform-card {
        padding: 1rem;
    }
    
    .ad-platform-name {
        font-size: 0.875rem;
    }
    
    .ad-platform-type {
        font-size: 0.75rem;
    }
    
    .ad-types-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .ad-type-card {
        padding: 1.5rem;
    }
    
    .ad-type-title {
        font-size: 1rem;
    }
    
    .ad-type-description {
        font-size: 0.75rem;
    }
    
    .page-header {
        padding: 5rem 0 2rem;
    }
    
    .page-title {
        font-size: 1.75rem;
        margin-bottom: 0.75rem;
    }
    
    .page-subtitle {
        font-size: 0.875rem;
    }
    
    .breadcrumb {
        font-size: 0.625rem;
        gap: 0.25rem;
    }
    
    .legal-content {
        padding: 2rem 0;
    }
    
    .legal-section {
        margin-bottom: 1rem;
    }
    
    .legal-title {
        font-size: 1.125rem;
    }
    
    .legal-text {
        font-size: 0.875rem;
        line-height: 1.7;
    }
    
    .legal-list {
        font-size: 0.875rem;
    }
}

/* Touch Device Optimizations */
@media (hover: none) and (pointer: coarse) {
    .btn:hover {
        transform: none;
    }
    
    .feature-card:hover {
        transform: none;
    }
    
    .service-card:hover {
        transform: none;
    }
    
    .team-card:hover {
        transform: none;
    }
    
    .news-card:hover {
        transform: none;
    }
    
    .social-link:hover {
        transform: none;
    }
    
    .nav-menu a::after {
        display: none;
    }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .hero,
    .stats-section,
    .contact-form,
    .mobile-menu-btn,
    .scroll-indicator,
    .preloader {
        display: none !important;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.5;
        color: #000;
        background: #fff;
    }
    
    .container {
        max-width: 100%;
        padding: 0;
    }
    
    .section {
        padding: 2rem 0;
        page-break-inside: avoid;
    }
    
    a {
        color: #000;
        text-decoration: underline;
    }
    
    .legal-content {
        padding: 1rem 0;
    }
}

/* Landscape Mode on Mobile */
@media (max-height: 500px) and (orientation: landscape) {
    .hero {
        min-height: auto;
        padding: 4rem 0 2rem;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 0.875rem;
    }
    
    .hero-buttons {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* High DPI Displays */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .hero::before,
    .page-header::before {
        background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        /* Can be customized for dark mode */
    }
}