:root {
    --primary-color: #f5f5f5;
    --secondary-color: #ffffff;
    --bg-dark: #1a1a1a;
    --text-color: #333333;
    --text-gray: #666666;
    --accent-color: #0066ff;
    --text-dark: #1a1a1a;
    --text-light: #666666;
    --transition: all 0.3s ease;
}

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

a {
    text-decoration: none;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--primary-color);
}

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

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(10px);
    padding: 8px 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    font-size: 24px;
    font-weight: 700;
    color: #ffffff;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-menu a {
    color: #ffffff;
    text-decoration: none;
    font-size: 16px;
    transition: var(--transition);
    padding: 5px 10px;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--accent-color);
}

.nav-full {
    display: inline;
}

.nav-short {
    display: none;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: #ffffff;
    margin: 3px 0;
    transition: var(--transition);
}

/* 首页视频展示 */
.featured-video {
    padding: 60px 0 60px;
    background: var(--primary-color);
}

.section-title {
    text-align: center;
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 36px;
    color: var(--text-dark);
    position: relative;
    padding-bottom: 14px;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 44px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 2px;
}

.featured-videos-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    max-width: 1400px;
    margin: 0 auto;
}

.featured-video-item {
    background: var(--secondary-color);
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
}

.featured-video-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.case-play-btn {
    width: 56px;
    height: 56px;
    background: rgba(255,255,255,0.15);
    border: 2px solid rgba(255,255,255,0.7);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s, background 0.2s;
}

.case-video-card:hover .case-play-btn {
    transform: scale(1.12);
    background: rgba(255,255,255,0.25);
}

.video-title {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-dark);
    text-align: center;
}

.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    border-radius: 10px;
    background: #000;
}

.video-container iframe,
.video-container video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}


/* 产品列表 */
.products {
    padding: 60px 0;
    background: var(--primary-color);
}

.products-list {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.product-item {
    background: var(--secondary-color);
    border-radius: 15px;
    overflow: hidden;
    transition: var(--transition);
    cursor: pointer;
}

.product-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 102, 255, 0.2);
}

.product-item .product-img {
    width: 100%;
    aspect-ratio: 4/3;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 0;
    object-fit: cover;
    display: block;
}

.product-info {
    padding: 10px 14px;
}

.product-info h3 {
    font-size: 15px;
    margin-bottom: 0;
    color: var(--text-dark);
    text-align: center;
}

.product-info p {
    font-size: 16px;
    color: var(--text-gray);
    line-height: 1.8;
}

/* 关于我们 */
.about {
    background: var(--primary-color);
}

/* 统一区块小标题（带蓝线装饰） */
.about-section-title {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-dark);
    text-align: center;
    margin-bottom: 28px;
    position: relative;
    padding-bottom: 14px;
}

.about-section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 44px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 2px;
}

/* 顶部标题区 */
.about-hero {
    padding: 50px 0 24px;
    text-align: center;
}

.about-hero-title {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 10px;
}

.about-hero-sub {
    font-size: 16px;
    color: var(--text-gray);
}

/* 数据亮点带 */
.about-stats-band {
    background: var(--accent-color);
    padding: 36px 0;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.stat-item {
    text-align: center;
}

.stat-item h4 {
    font-size: 40px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 6px;
}

.stat-item p {
    font-size: 14px;
    color: rgba(255,255,255,0.85);
}

/* 企业简介 */
.about-intro {
    max-width: 820px;
    margin: 0 auto;
}

.about-intro-title {}

.about-intro p {
    font-size: 16px;
    line-height: 1.85;
    color: var(--text-gray);
    margin-bottom: 14px;
    text-indent: 2em;
}

/* 业务范围 */
.business-scope {
    max-width: 820px;
    margin: 48px auto 0;
    text-align: center;
}

.business-scope-title {}

.scope-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    justify-content: center;
}

.scope-tag {
    display: inline-block;
    padding: 10px 28px;
    border: 2px solid var(--accent-color);
    color: var(--accent-color);
    border-radius: 30px;
    font-size: 15px;
    font-weight: 500;
    background: rgba(0,102,255,0.04);
    transition: background 0.2s, color 0.2s;
}

.scope-tag:hover {
    background: var(--accent-color);
    color: #fff;
}

/* 合作单位 */
.partners {
    padding: 40px 0;
    background: var(--primary-color);
}

.partners-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
}

.partner-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: var(--secondary-color);
    border-radius: 10px;
    transition: var(--transition);
}

.partner-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.partner-item img {
    max-width: 100%;
    max-height: 80px;
    object-fit: contain;
}

.partner-name {
    font-size: 14px;
    color: var(--text-dark);
    text-align: center;
    margin-top: 10px;
}

/* 页脚 */
.footer {
    background: var(--bg-dark);
    color: #ffffff;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    font-size: 18px;
    margin-bottom: 20px;
    font-weight: 600;
}

.footer-col p {
    font-size: 14px;
    color: #cccccc;
    line-height: 1.6;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col a {
    color: #cccccc;
    text-decoration: none;
    font-size: 14px;
    transition: var(--transition);
}

.footer-col a:hover {
    color: var(--accent-color);
}

.social-links {
    display: flex;
    gap: 15px;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #999999;
    font-size: 14px;
}

.footer-bottom a {
    color: var(--accent-color);
    text-decoration: none;
}

/* 二维码弹窗 */
.qr-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 2000;
    justify-content: center;
    align-items: center;
}

.qr-modal.active {
    display: flex;
}

.qr-modal-content {
    position: relative;
    width: 320px;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0,0,0,0.4);
}

.qr-close {
    position: absolute;
    top: 12px;
    right: 16px;
    font-size: 28px;
    cursor: pointer;
    color: rgba(255,255,255,0.8);
    transition: color 0.2s;
    line-height: 1;
    z-index: 1;
}

.qr-close:hover {
    color: #fff;
}

/* 拖动排序样式 */
.drag-mode .drag-item {
    cursor: move;
}

.drag-item.dragging {
    opacity: 0.5;
}

.drag-item.drag-over {
    border-top: 3px solid var(--accent-color);
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .featured-videos-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .partners-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* 手机端导航：标题栏内联显示 首页 产品 科研 关于 */
@media (max-width: 992px) {
    .hamburger {
        display: none !important;
    }
    
    .nav-menu {
        position: static !important;
        display: flex !important;
        flex-direction: row;
        gap: 8px;
        padding: 0;
        width: auto;
        min-width: auto;
        height: auto;
        background: transparent;
    }
    
    .nav-menu li {
        width: auto;
    }
    
    .nav-menu a {
        display: inline-block;
        padding: 6px 10px;
        font-size: 15px;
        min-height: auto;
        line-height: 1.2;
        border: none;
        border-radius: 4px;
    }
    
    .nav-full {
        display: none;
    }
    
    .nav-short {
        display: inline;
    }
    
    .navbar .logo h1 {
        font-size: 18px;
    }
    
    .featured-videos-grid {
        grid-template-columns: 1fr;
    }
    
    .products-list {
        grid-template-columns: 1fr;
    }
    
    
    .partners-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: 30px;
    }
}

@media (max-width: 480px) {
    .section-title {
        font-size: 28px;
    }

    .about-hero-title {
        font-size: 28px;
    }

    .about-stats {
        grid-template-columns: repeat(3, 1fr);
        gap: 10px;
    }

    .stat-item h4 {
        font-size: 28px;
    }
    
    .partners-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

/* ========== 产品/项目详情页 ========== */
.item-detail-page {
    padding: 55px 0 40px;
    background: var(--primary-color);
    min-height: calc(100vh - 200px);
}

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

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 16px;
    padding: 8px 16px;
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    color: var(--text-color);
    font-size: 14px;
    text-decoration: none;
    transition: border-color 0.2s, color 0.2s, box-shadow 0.2s;
}

.back-link:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
    box-shadow: 0 2px 8px rgba(0,102,255,0.1);
}

.detail-content {
    background: var(--secondary-color);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    padding: 30px 40px 40px;
}

.detail-title {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 30px;
}

.image-grid-product {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    margin-bottom: 24px;
}

.image-grid-product .image-card {
    width: 100%;
    max-width: 100%;
    aspect-ratio: 4/3;
    border-radius: 12px;
    overflow: hidden;
    cursor: pointer;
    background: #eee;
}

.image-grid-product .image-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.2s;
}

.image-grid-product .image-card:hover img { transform: scale(1.03); }

.detail-description {
    font-size: 18px;
    line-height: 2;
    color: var(--text-gray);
    margin-bottom: 30px;
}

.video-section-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 16px;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.video-card {
    border-radius: 10px;
    overflow: hidden;
    background: #111;
    aspect-ratio: 16/9;
    position: relative;
}

.video-card iframe,
.video-card video {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
}

@media (min-width: 601px) {
    .video-card-desktop { cursor: pointer; }
    .video-card-overlay {
        position: absolute;
        inset: 0;
        z-index: 2;
        display: flex;
        align-items: center;
        justify-content: center;
        background: rgba(0,0,0,0.15);
        transition: background 0.2s;
    }
    .video-card-desktop:hover .video-card-overlay { background: rgba(0,0,0,0.45); }
    .video-card-desktop:hover .video-play-icon { transform: scale(1.12); }
    .video-play-icon {
        width: 56px;
        height: 56px;
        background: rgba(255,255,255,0.2);
        border: 2px solid rgba(255,255,255,0.8);
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        transition: transform 0.2s;
        pointer-events: none;
    }
}

.video-modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.88);
    z-index: 9999;
    align-items: center;
    justify-content: center;
}
.video-modal-overlay.active { display: flex; }
.video-modal-box {
    position: relative;
    width: 80vw;
    max-width: 960px;
    aspect-ratio: 16/9;
    background: #000;
    border-radius: 10px;
    overflow: hidden;
}
.video-modal-box iframe,
.video-modal-box video {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
}
.video-modal-close {
    position: fixed;
    top: 20px;
    right: 28px;
    color: #fff;
    font-size: 36px;
    cursor: pointer;
    user-select: none;
    line-height: 1;
}

.item-detail-loading {
    text-align: center;
    padding: 100px 20px;
    font-size: 18px;
    color: var(--text-gray);
}

.detail-lightbox {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.88);
    z-index: 9999;
    align-items: center;
    justify-content: center;
}
.detail-lightbox.active { display: flex; }
.detail-lightbox img {
    max-width: 90vw;
    max-height: 90vh;
    object-fit: contain;
    border-radius: 6px;
}
.lightbox-close {
    position: fixed;
    top: 20px;
    right: 28px;
    color: #fff;
    font-size: 36px;
    cursor: pointer;
    user-select: none;
    line-height: 1;
}
.lightbox-prev,
.lightbox-next {
    position: fixed;
    top: 50%;
    transform: translateY(-50%);
    color: #fff;
    font-size: 40px;
    cursor: pointer;
    padding: 10px 18px;
    user-select: none;
    background: rgba(0,0,0,0.3);
    border-radius: 6px;
}
.lightbox-prev { left: 16px; }
.lightbox-next { right: 16px; }
.lightbox-counter {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    color: rgba(255,255,255,0.7);
    font-size: 14px;
}

@media (max-width: 600px) {
    .detail-content { padding: 24px 16px; }
    .detail-title { font-size: 26px; }
    .detail-description { font-size: 16px; }
    .image-grid-product { grid-template-columns: 1fr; }
    .video-grid { grid-template-columns: 1fr; }
}