:root {
    --primary-color: #ff6600; /* 竞技橙 */
    --secondary-color: #00ccff; /* 科技蓝 */
    --bg-dark: #0a0a12;
    --bg-card: #161622;
    --text-light: #ffffff;
    --text-gray: #a0a0a0;
    --gradient-primary: linear-gradient(135deg, #ff6600 0%, #ff3300 100%);
    --gradient-secondary: linear-gradient(135deg, #00ccff 0%, #0066ff 100%);
    --shadow-card: 0 10px 30px rgba(0, 0, 0, 0.5);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-light);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

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

/* Header */
.site-header {
    background-color: rgba(10, 10, 18, 0.9);
    backdrop-filter: blur(10px);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.site-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: bold;
    font-size: 1.2rem;
    color: var(--text-light);
}

.logo img {
    border-radius: 50%;
}

.main-nav ul {
    display: flex;
    gap: 30px;
}

.main-nav a {
    color: var(--text-gray);
    font-weight: 500;
    position: relative;
}

.main-nav a.active,
.main-nav a:hover {
    color: var(--primary-color);
}

.main-nav a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition);
}

.main-nav a:hover::after,
.main-nav a.active::after {
    width: 100%;
}

/* Mobile Menu */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--text-light);
    transition: var(--transition);
}

/* Hero Section */
.hero {
    position: relative;
    height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    margin-top: 70px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    z-index: -2;
    transform: scale(1.1);
    animation: zoomIn 20s infinite alternate;
}

@keyframes zoomIn {
    from { transform: scale(1.1); }
    to { transform: scale(1.2); }
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, rgba(10,10,18,0.3), var(--bg-dark));
    z-index: -1;
}

.hero-content {
    z-index: 1;
    max-width: 800px;
}

.badge {
    display: inline-block;
    padding: 5px 15px;
    background: rgba(255, 102, 0, 0.2);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
    border-radius: 20px;
    font-size: 0.9rem;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    line-height: 1.2;
    background: linear-gradient(to right, #fff, #ccc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-gray);
    margin-bottom: 40px;
}

.hero-actions {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.btn {
    padding: 12px 30px;
    border-radius: 30px;
    font-weight: bold;
    cursor: pointer;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    border: none;
    box-shadow: 0 5px 15px rgba(255, 102, 0, 0.4);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(255, 102, 0, 0.6);
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.btn-outline:hover {
    border-color: var(--text-light);
    background: rgba(255, 255, 255, 0.1);
}

/* Sections */
.section {
    padding: 80px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    position: relative;
    display: inline-block;
}

.section-header h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--gradient-primary);
    margin: 15px auto 0;
    border-radius: 2px;
}

.section-header p {
    color: var(--text-gray);
}

.bg-dark {
    background-color: #0f0f1a;
}

/* Grid Layouts */
.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

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

/* Video Cards */
.video-card {
    background: var(--bg-card);
    border-radius: 15px;
    overflow: hidden;
    transition: var(--transition);
    border: 1px solid rgba(255, 255, 255, 0.05);
    position: relative;
}

.video-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-card);
    border-color: var(--primary-color);
}

.video-thumb {
    position: relative;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    overflow: hidden;
}

.video-thumb img,
.placeholder-thumb {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.video-card:hover .video-thumb img {
    transform: scale(1.1);
}

.play-icon {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    width: 50px;
    height: 50px;
    background: rgba(0, 0, 0, 0.7);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 20px;
    transition: var(--transition);
    border: 2px solid var(--primary-color);
}

.video-card:hover .play-icon {
    transform: translate(-50%, -50%) scale(1);
}

.duration {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.8rem;
}

.video-info {
    padding: 20px;
}

.video-info h3 {
    font-size: 1.1rem;
    margin-bottom: 10px;
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-info p {
    font-size: 0.9rem;
    color: var(--text-gray);
    margin-bottom: 15px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-gray);
}

/* Expert Cards */
.expert-card {
    background: var(--bg-card);
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: var(--transition);
}

.expert-card:hover {
    border-color: var(--secondary-color);
    transform: translateY(-5px);
}

.expert-avatar {
    width: 100px;
    height: 100px;
    margin: 0 auto 20px;
    border-radius: 50%;
    overflow: hidden;
    border: 3px solid var(--secondary-color);
}

.expert-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.expert-card h3 {
    margin-bottom: 5px;
}

.expert-card .title {
    color: var(--secondary-color);
    font-size: 0.9rem;
    margin-bottom: 15px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.expert-card .desc {
    color: var(--text-gray);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

.btn-sm {
    padding: 8px 20px;
    font-size: 0.9rem;
}

/* Testimonials */
.testimonial-card {
    background: rgba(255, 255, 255, 0.05);
    padding: 30px;
    border-radius: 15px;
    position: relative;
}

.testimonial-card::before {
    content: '"';
    position: absolute;
    top: 10px;
    left: 20px;
    font-size: 4rem;
    color: rgba(255, 255, 255, 0.1);
    font-family: serif;
}

.quote {
    font-style: italic;
    margin-bottom: 20px;
    color: #ddd;
}

.user-info {
    display: flex;
    flex-direction: column;
}

.user-info .name {
    font-weight: bold;
    color: var(--primary-color);
}

.user-info .role {
    font-size: 0.8rem;
    color: var(--text-gray);
}

/* Footer */
.site-footer {
    background: #050508;
    padding: 80px 0 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 60px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: bold;
    font-size: 1.2rem;
    margin-bottom: 20px;
}

.footer-col p {
    color: var(--text-gray);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

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

.social-links a {
    width: 35px;
    height: 35px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
}

.social-links a:hover {
    background: var(--primary-color);
}

.footer-col h4 {
    margin-bottom: 20px;
    font-size: 1.1rem;
}

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

.footer-col ul li a {
    color: var(--text-gray);
}

.footer-col ul li a:hover {
    color: var(--primary-color);
    padding-left: 5px;
}

.qr-code {
    border-radius: 10px;
    margin-bottom: 10px;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--text-gray);
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 1024px) {
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }
    
    .main-nav {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--bg-card);
        padding: 20px;
        transform: translateY(-100%);
        transition: var(--transition);
        z-index: 999;
        opacity: 0;
        pointer-events: none;
    }
    
    .main-nav.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    
    .main-nav ul {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .grid-4, .grid-3 {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
}