/* ============================================
   兄妹乱伦 - 原创样式表
   品牌：兄妹乱伦 | nudmven.cn
   配色：赛博霓虹风
   ============================================ */

/* --- CSS Variables --- */
:root {
    --v51-bg: #0a0e1a;
    --v51-bg2: #111827;
    --v51-card: #1a2035;
    --v51-primary: #6c5ce7;
    --v51-secondary: #00cec9;
    --v51-accent: #fd79a8;
    --v51-text: #e2e8f0;
    --v51-text2: #94a3b8;
    --v51-border: #2d3748;
    --v51-gradient: linear-gradient(135deg, #6c5ce7, #00cec9);
    --v51-shadow: 0 4px 24px rgba(108, 92, 231, 0.15);
    --v51-radius: 12px;
    --v51-transition: all 0.3s ease;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; overflow-x: hidden; }
body {
    font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
    background: var(--v51-bg);
    color: var(--v51-text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}
a { color: var(--v51-secondary); text-decoration: none; transition: var(--v51-transition); }
a:hover { color: var(--v51-accent); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

/* --- Container --- */
.v51-container { max-width: 1200px; margin: 0 auto; padding: 0 20px; overflow: hidden; }

/* --- Header --- */
.v51-header {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(10, 14, 26, 0.92);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--v51-border);
    padding: 0 20px;
    overflow: hidden;
}
.v51-header-inner {
    max-width: 1200px; margin: 0 auto;
    display: flex; align-items: center; justify-content: space-between;
    height: 68px;
}
.v51-logo img { height: 42px; width: auto; }
.v51-nav { display: flex; gap: 6px; }
.v51-nav a {
    color: var(--v51-text2); font-size: 15px; padding: 8px 14px;
    border-radius: 8px; transition: var(--v51-transition); font-weight: 500;
}
.v51-nav a:hover, .v51-nav a.active {
    color: var(--v51-text); background: rgba(108, 92, 231, 0.15);
}
.v51-menu-btn {
    display: none; background: none; border: none; color: var(--v51-text);
    font-size: 24px; cursor: pointer; padding: 8px;
}

/* --- Search Bar --- */
.v51-search-bar {
    background: var(--v51-bg2); border-bottom: 1px solid var(--v51-border);
    padding: 12px 20px; margin-top: 68px;
}
.v51-search-inner {
    max-width: 680px; margin: 0 auto; display: flex; gap: 10px;
}
.v51-search-input {
    flex: 1; background: var(--v51-card); border: 1px solid var(--v51-border);
    border-radius: 24px; padding: 10px 20px; color: var(--v51-text);
    font-size: 14px; outline: none; transition: var(--v51-transition);
}
.v51-search-input:focus { border-color: var(--v51-primary); box-shadow: 0 0 0 3px rgba(108,92,231,0.2); }
.v51-search-input::placeholder { color: var(--v51-text2); }
.v51-search-btn {
    background: var(--v51-gradient); border: none; color: #fff;
    padding: 10px 24px; border-radius: 24px; cursor: pointer;
    font-size: 14px; font-weight: 600; transition: var(--v51-transition);
}
.v51-search-btn:hover { opacity: 0.85; transform: translateY(-1px); }

/* --- Hero Banner --- */
.v51-hero {
    position: relative; overflow: hidden;
    min-height: 480px; display: flex; align-items: center;
    background: var(--v51-bg2);
}
.v51-hero-bg {
    position: absolute; inset: 0; z-index: 0;
    background-size: cover; background-position: center;
    filter: brightness(0.4);
}
.v51-hero-content {
    position: relative; z-index: 1; max-width: 1200px;
    margin: 0 auto; padding: 80px 20px; text-align: center;
}
.v51-hero h1 {
    font-size: 42px; font-weight: 800; margin-bottom: 16px;
    background: var(--v51-gradient); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
    line-height: 1.3;
}
.v51-hero h2 {
    font-size: 20px; color: var(--v51-text2); font-weight: 400;
    margin-bottom: 32px; max-width: 600px; margin-left: auto; margin-right: auto;
}
.v51-hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.v51-btn-primary {
    background: var(--v51-gradient); color: #fff; padding: 14px 36px;
    border-radius: 30px; font-size: 16px; font-weight: 600;
    border: none; cursor: pointer; transition: var(--v51-transition);
    display: inline-block;
}
.v51-btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(108,92,231,0.4); color: #fff; }
.v51-btn-outline {
    background: transparent; color: var(--v51-secondary);
    padding: 14px 36px; border-radius: 30px; font-size: 16px;
    font-weight: 600; border: 2px solid var(--v51-secondary);
    cursor: pointer; transition: var(--v51-transition); display: inline-block;
}
.v51-btn-outline:hover { background: var(--v51-secondary); color: var(--v51-bg); }

/* --- Section Common --- */
.v51-section { padding: 72px 0; overflow: hidden; }
.v51-section-alt { background: var(--v51-bg2); }
.v51-section-title {
    text-align: center; margin-bottom: 48px;
}
.v51-section-title h2 {
    font-size: 32px; font-weight: 700; margin-bottom: 12px;
    color: var(--v51-text);
}
.v51-section-title h2 span {
    background: var(--v51-gradient); -webkit-background-clip: text;
    -webkit-text-fill-color: transparent; background-clip: text;
}
.v51-section-title p {
    color: var(--v51-text2); font-size: 16px; max-width: 600px;
    margin: 0 auto;
}

/* --- Video Card Grid --- */
.v51-grid { display: grid; gap: 24px; }
.v51-grid-3 { grid-template-columns: repeat(3, 1fr); }
.v51-grid-4 { grid-template-columns: repeat(4, 1fr); }
.v51-grid-2 { grid-template-columns: repeat(2, 1fr); }

.v51-video-card {
    background: var(--v51-card); border-radius: var(--v51-radius);
    overflow: hidden; transition: var(--v51-transition);
    border: 1px solid var(--v51-border);
}
.v51-video-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--v51-shadow);
    border-color: var(--v51-primary);
}
.v51-video-thumb {
    position: relative; padding-top: 56.25%; overflow: hidden;
}
.v51-video-thumb img,
.v51-video-thumb video,
.v51-video-thumb .v51-h5-video {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    object-fit: cover; transition: transform 0.4s ease;
}
.v51-video-card:hover .v51-video-thumb img,
.v51-video-card:hover .v51-video-thumb video,
.v51-video-card:hover .v51-video-thumb .v51-h5-video { transform: scale(1.08); }
.v51-play-btn {
    position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);
    width: 56px; height: 56px; background: rgba(108, 92, 231, 0.85);
    border-radius: 50%; display: flex; align-items: center; justify-content: center;
    opacity: 0; transition: var(--v51-transition); z-index: 2;
}
.v51-play-btn::after {
    content: ''; display: block; width: 0; height: 0;
    border-style: solid; border-width: 10px 0 10px 18px;
    border-color: transparent transparent transparent #fff;
    margin-left: 4px;
}
.v51-video-card:hover .v51-play-btn { opacity: 1; }
.v51-video-info { padding: 16px; }
.v51-video-info h3 {
    font-size: 15px; font-weight: 600; margin-bottom: 8px;
    color: var(--v51-text); line-height: 1.4;
    display: -webkit-box; -webkit-line-clamp: 2;
    -webkit-box-orient: vertical; overflow: hidden;
}
.v51-video-meta {
    display: flex; gap: 12px; font-size: 12px; color: var(--v51-text2);
}
.v51-video-meta span { display: flex; align-items: center; gap: 4px; }
.v51-video-tag {
    position: absolute; top: 10px; left: 10px; z-index: 2;
    background: var(--v51-accent); color: #fff; font-size: 11px;
    padding: 3px 10px; border-radius: 12px; font-weight: 600;
}
.v51-video-duration {
    position: absolute; bottom: 10px; right: 10px; z-index: 2;
    background: rgba(0,0,0,0.75); color: #fff; font-size: 12px;
    padding: 2px 8px; border-radius: 4px;
}

/* --- Feature Cards --- */
.v51-feature-card {
    background: var(--v51-card); border-radius: var(--v51-radius);
    padding: 32px 24px; text-align: center;
    border: 1px solid var(--v51-border); transition: var(--v51-transition);
}
.v51-feature-card:hover {
    border-color: var(--v51-primary);
    transform: translateY(-4px); box-shadow: var(--v51-shadow);
}
.v51-feature-icon {
    width: 64px; height: 64px; margin: 0 auto 20px;
    background: var(--v51-gradient); border-radius: 16px;
    display: flex; align-items: center; justify-content: center;
    font-size: 28px;
}
.v51-feature-card h3 { font-size: 18px; margin-bottom: 10px; color: var(--v51-text); }
.v51-feature-card p { font-size: 14px; color: var(--v51-text2); line-height: 1.6; }

/* --- Expert Section --- */
.v51-expert-card {
    background: var(--v51-card); border-radius: var(--v51-radius);
    padding: 32px; text-align: center;
    border: 1px solid var(--v51-border); transition: var(--v51-transition);
}
.v51-expert-card:hover { border-color: var(--v51-secondary); box-shadow: var(--v51-shadow); }
.v51-expert-avatar {
    width: 100px; height: 100px; border-radius: 50%; margin: 0 auto 16px;
    object-fit: cover; border: 3px solid var(--v51-primary);
}
.v51-expert-card h3 { font-size: 18px; margin-bottom: 4px; }
.v51-expert-card .v51-expert-role { color: var(--v51-accent); font-size: 14px; margin-bottom: 12px; }
.v51-expert-card p { font-size: 13px; color: var(--v51-text2); margin-bottom: 16px; }
.v51-expert-links { display: flex; gap: 10px; justify-content: center; }
.v51-expert-links a {
    padding: 6px 16px; border-radius: 20px; font-size: 13px;
    border: 1px solid var(--v51-border); color: var(--v51-text2);
}
.v51-expert-links a:hover { border-color: var(--v51-primary); color: var(--v51-primary); }

/* --- Partners Logo Wall --- */
.v51-partners { display: flex; flex-wrap: wrap; justify-content: center; gap: 32px; align-items: center; }
.v51-partner-item {
    background: var(--v51-card); border: 1px solid var(--v51-border);
    border-radius: 10px; padding: 16px 28px; font-size: 16px;
    font-weight: 600; color: var(--v51-text2); transition: var(--v51-transition);
}
.v51-partner-item:hover { border-color: var(--v51-primary); color: var(--v51-text); }

/* --- How-To Steps --- */
.v51-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.v51-step {
    text-align: center; padding: 28px 20px;
    background: var(--v51-card); border-radius: var(--v51-radius);
    border: 1px solid var(--v51-border); position: relative;
}
.v51-step-num {
    width: 48px; height: 48px; border-radius: 50%;
    background: var(--v51-gradient); color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-size: 20px; font-weight: 700; margin: 0 auto 16px;
}
.v51-step h3 { font-size: 16px; margin-bottom: 8px; }
.v51-step p { font-size: 13px; color: var(--v51-text2); }

/* --- FAQ --- */
.v51-faq-list { max-width: 800px; margin: 0 auto; }
.v51-faq-item {
    background: var(--v51-card); border: 1px solid var(--v51-border);
    border-radius: var(--v51-radius); margin-bottom: 12px; overflow: hidden;
}
.v51-faq-q {
    padding: 18px 24px; cursor: pointer; display: flex;
    justify-content: space-between; align-items: center;
    font-weight: 600; font-size: 15px; transition: var(--v51-transition);
}
.v51-faq-q:hover { color: var(--v51-primary); }
.v51-faq-q::after { content: '+'; font-size: 22px; color: var(--v51-primary); transition: var(--v51-transition); }
.v51-faq-item.open .v51-faq-q::after { content: '-'; }
.v51-faq-a {
    max-height: 0; overflow: hidden; transition: max-height 0.35s ease;
    padding: 0 24px; color: var(--v51-text2); font-size: 14px; line-height: 1.7;
}
.v51-faq-item.open .v51-faq-a { max-height: 300px; padding: 0 24px 18px; }

/* --- Reviews --- */
.v51-review-card {
    background: var(--v51-card); border-radius: var(--v51-radius);
    padding: 24px; border: 1px solid var(--v51-border);
}
.v51-review-header { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.v51-review-avatar {
    width: 44px; height: 44px; border-radius: 50%;
    background: var(--v51-gradient); display: flex; align-items: center;
    justify-content: center; color: #fff; font-weight: 700; font-size: 18px;
}
.v51-review-name { font-weight: 600; font-size: 15px; }
.v51-review-date { font-size: 12px; color: var(--v51-text2); }
.v51-review-stars { color: #f1c40f; font-size: 14px; margin-bottom: 8px; }
.v51-review-card p { font-size: 14px; color: var(--v51-text2); line-height: 1.6; }

/* --- Contact Section --- */
.v51-contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.v51-contact-info { display: flex; flex-direction: column; gap: 16px; }
.v51-contact-item {
    display: flex; gap: 12px; align-items: flex-start;
    padding: 16px; background: var(--v51-card); border-radius: 10px;
    border: 1px solid var(--v51-border);
}
.v51-contact-item strong { color: var(--v51-primary); min-width: 80px; display: inline-block; }
.v51-contact-qrcodes { display: flex; gap: 24px; justify-content: center; }
.v51-qrcode-item { text-align: center; }
.v51-qrcode-item img { width: 140px; height: 140px; border-radius: 10px; margin-bottom: 8px; }
.v51-qrcode-item p { font-size: 13px; color: var(--v51-text2); }

/* --- Social Share --- */
.v51-share { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.v51-share-btn {
    padding: 10px 24px; border-radius: 24px; font-size: 14px;
    font-weight: 500; border: 1px solid var(--v51-border);
    color: var(--v51-text2); background: var(--v51-card);
    cursor: pointer; transition: var(--v51-transition);
}
.v51-share-btn:hover { border-color: var(--v51-primary); color: var(--v51-primary); }

/* --- Friend Links --- */
.v51-friend-links {
    border-top: 1px solid var(--v51-border);
    padding-top: 20px;
    margin-top: 20px;
}
.v51-friend-links h4 {
    font-size: 14px;
    color: var(--v51-text2);
    margin-bottom: 10px;
}
.v51-friend-links a {
    font-size: 13px;
    color: var(--v51-text2);
    transition: color 0.3s;
}
.v51-friend-links a:hover {
    color: var(--v51-secondary);
}

/* --- Footer --- */
.v51-footer {
    background: var(--v51-bg2); border-top: 1px solid var(--v51-border);
    padding: 48px 0 24px; overflow: hidden;
}
.v51-footer-grid {
    display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
    margin-bottom: 32px;
}
.v51-footer-brand img { height: 36px; margin-bottom: 12px; }
.v51-footer-brand p { font-size: 13px; color: var(--v51-text2); line-height: 1.6; }
.v51-footer h4 { font-size: 15px; margin-bottom: 16px; color: var(--v51-text); }
.v51-footer-links a { display: block; color: var(--v51-text2); font-size: 13px; padding: 4px 0; }
.v51-footer-links a:hover { color: var(--v51-secondary); }
.v51-footer-bottom {
    border-top: 1px solid var(--v51-border); padding-top: 20px;
    text-align: center; font-size: 13px; color: var(--v51-text2);
}

/* --- Breadcrumb --- */
.v51-breadcrumb {
    padding: 16px 0; font-size: 13px; color: var(--v51-text2);
    margin-top: 68px;
}
.v51-breadcrumb a { color: var(--v51-secondary); }
.v51-breadcrumb span { margin: 0 8px; }

/* --- Page Hero (inner pages) --- */
.v51-page-hero {
    background: var(--v51-bg2); padding: 48px 0; text-align: center;
    border-bottom: 1px solid var(--v51-border);
}
.v51-page-hero h1 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.v51-page-hero p { color: var(--v51-text2); font-size: 16px; }

/* --- Community Cards --- */
.v51-community-card {
    background: var(--v51-card); border-radius: var(--v51-radius);
    padding: 28px; border: 1px solid var(--v51-border);
    transition: var(--v51-transition);
}
.v51-community-card:hover { border-color: var(--v51-accent); transform: translateY(-4px); }
.v51-community-icon { font-size: 36px; margin-bottom: 16px; }
.v51-community-card h3 { font-size: 18px; margin-bottom: 10px; }
.v51-community-card p { font-size: 14px; color: var(--v51-text2); }

/* --- Tags --- */
.v51-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.v51-tag {
    background: rgba(108, 92, 231, 0.12); color: var(--v51-primary);
    padding: 4px 12px; border-radius: 16px; font-size: 12px;
}

/* --- Noise Tags (hidden SEO) --- */
.v51-seo-noise {
    position: absolute; width: 1px; height: 1px; overflow: hidden;
    clip: rect(0,0,0,0); white-space: nowrap; border: 0;
    opacity: 0; pointer-events: none;
}

/* --- Mobile Menu Overlay --- */
.v51-mobile-menu {
    display: none; position: fixed; top: 68px; left: 0; right: 0; bottom: 0;
    background: rgba(10, 14, 26, 0.98); z-index: 999; padding: 24px;
}
.v51-mobile-menu.active { display: block; }
.v51-mobile-menu a {
    display: block; padding: 14px 0; font-size: 18px;
    color: var(--v51-text); border-bottom: 1px solid var(--v51-border);
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .v51-grid-4 { grid-template-columns: repeat(3, 1fr); }
    .v51-footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
    .v51-nav { display: none; }
    .v51-menu-btn { display: block; }
    .v51-grid-3, .v51-grid-4 { grid-template-columns: repeat(2, 1fr); }
    .v51-grid-2 { grid-template-columns: 1fr; }
    .v51-hero h1 { font-size: 28px; }
    .v51-hero h2 { font-size: 16px; }
    .v51-section { padding: 48px 0; }
    .v51-section-title h2 { font-size: 24px; }
    .v51-steps { grid-template-columns: repeat(2, 1fr); }
    .v51-contact-grid { grid-template-columns: 1fr; }
    .v51-footer-grid { grid-template-columns: 1fr; }
    .v51-hero-btns { flex-direction: column; align-items: center; }
}
@media (max-width: 480px) {
    .v51-grid-3, .v51-grid-4 { grid-template-columns: 1fr; }
    .v51-steps { grid-template-columns: 1fr; }
    .v51-hero { min-height: 360px; }
}