:root {
    --primary: #1a3a6c;
    --secondary: #2c5282;
    --accent: #4c7db5;
    --light: #f0f4f8;
    --dark: #0d1b2a;
    --gray: #718096;
    --light-gray: #e2e8f0;
    --white: #ffffff;
    --warning: #e67e22;
    --lang-bg: #f8fafc;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: var(--dark);
    line-height: 1.6;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.tech-header {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 60px 0;
    text-align: center;
    margin-bottom: 60px;
}

.tech-header h1 {
    font-size: 2.8rem;
    margin-bottom: 15px;
    font-weight: 700;
}

.tech-header p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 700px;
    margin: 0 auto;
}

.tech-nav {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-bottom: 50px;
    flex-wrap: wrap;
}

.tech-nav-btn {
    padding: 10px 24px;
    background: var(--white);
    border: 1px solid var(--light-gray);
    border-radius: 6px;
    color: var(--dark);
    font-weight: 500;
    font-size: 14px;
    text-decoration: none;
    transition: all 0.3s ease;
}

.tech-nav-btn:hover, .tech-nav-btn.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.tech-content {
    margin-bottom: 80px;
}

.tech-section {
    background: var(--white);
    border-radius: 8px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.06);
    padding: 40px;
    margin-bottom: 40px;
}

.tech-section h2 {
    color: var(--primary);
    font-size: 1.8rem;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--light);
}

.tech-section h3 {
    color: var(--secondary);
    font-size: 1.4rem;
    margin: 25px 0 15px;
}

.tech-section p {
    color: var(--gray);
    line-height: 1.8;
    margin-bottom: 20px;
}

.tech-section ul {
    margin-left: 25px;
    margin-bottom: 20px;
    color: var(--gray);
}

.tech-section ul li {
    margin-bottom: 10px;
    line-height: 1.7;
}

.tech-params-table {
    width: 100% !important;
    border-collapse: collapse !important;
    margin: 30px 0 !important;
    table-layout: fixed !important;
}

.tech-params-table th,
.tech-params-table td {
    text-align: center !important;
    vertical-align: middle !important;
    border: 1px solid var(--light-gray) !important;
    padding: 14px 10px !important;
    font-size: 14px !important;
    white-space: normal !important;
    word-wrap: break-word !important;
}

.tech-params-table th {
    background-color: var(--light) !important;
    color: var(--primary) !important;
    font-weight: 600 !important;
}

.tech-params-table tr:nth-child(even) {
    background-color: var(--lang-bg) !important;
}

.tech-params-table tr:hover {
    background-color: rgba(76, 125, 181, 0.05) !important;
}

.param-note {
    font-size: 14px;
    color: var(--warning);
    margin-top: 10px;
    font-style: italic;
}

.tech-videos {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.video-card {
    background: var(--white);
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    overflow: hidden;
    transition: all 0.3s ease;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.video-thumbnail {
    height: 200px;
    position: relative;
    overflow: hidden;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.video-card:hover .video-thumbnail img {
    transform: scale(1.05);
}

.play-icon {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: rgba(26, 58, 108, 0.8);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
    text-decoration: none;
    transition: all 0.3s ease;
}

.play-icon:hover {
    background: var(--primary);
    transform: translate(-50%, -50%) scale(1.1);
}

.video-info {
    padding: 20px;
}

.video-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 10px;
}

.video-desc {
    font-size: 14px;
    color: var(--gray);
    line-height: 1.6;
}

/* 视频弹窗终极美化 */
.video-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 9999;
    align-items: center;
    justify-content: center;
}

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

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: relative;
    z-index: 10;
    width: 92%;
    max-width: 1100px;
    background: #000;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0,0,0,0.5);
}

.close-modal {
    position: absolute;
    top: 12px;
    right: 12px;
    width: 36px;
    height: 36px;
    background: rgba(0,0,0,0.5);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    z-index: 11;
    transition: 0.2s;
    text-decoration: none;
}

.close-modal:hover {
    background: #ff3a3a;
    color: #fff;
}

.video-wrapper {
    position: relative;
    width: 100%;
    padding-top: 56.25%;
}

.modal-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    background: #000;
    border: none;
}

/* 响应式 */
@media (max-width: 992px) {
    .tech-header h1 { font-size: 2.2rem; }
    .tech-header { padding: 40px 0; }
    .tech-videos{grid-template-columns:repeat(2,1fr)!important;gap:25px!important;}
}

@media (max-width: 768px){
    .tech-header{padding:40px 0!important;}
    .tech-header h1{font-size:24px!important;}
    .tech-header p{font-size:14px!important;}
    .tech-nav{display:flex!important;overflow-x:auto!important;white-space:nowrap!important;padding-bottom:10px!important;gap:8px!important;}
    .tech-nav-btn{flex:0 0 auto!important;padding:10px 16px!important;font-size:14px!important;}
    .tech-params-table{width:100%!important;display:block!important;overflow-x:auto!important;}
    .tech-params-table table{width:100%!important;}
    .tech-videos{grid-template-columns:1fr!important;gap:20px!important;}
    .modal-content{width:95%!important;padding:0!important;}
    .close-modal {width:32px;height:32px;font-size:14px;}
}

@media (max-width: 576px) {
    .tech-header h1 { font-size: 1.8rem; }
    .tech-header p { font-size: 1rem; }
    .video-thumbnail { height: 180px; }
}