:root{
    --bg:#f7f8fb;
    --surface:#ffffff;
    --surface-soft:#eef3fa;
    --ink:#101827;
    --muted:#5f6b7a;
    --line:#dfe6ef;
    --accent:#2563eb;
    --accent-soft:#dbeafe;
    --shadow:0 24px 80px rgba(15,23,42,.08);
    --radius:28px;
    --container:1180px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
    margin:0;
    background:var(--bg);
    color:var(--ink);
    font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",Arial,sans-serif;
    line-height:1.7;
    text-rendering:optimizeLegibility;
}
a{color:inherit;text-decoration:none}
img,video{display:block;max-width:100%;height:auto}
button,input{font:inherit}
.container{width:min(var(--container),calc(100% - 36px));margin-inline:auto}
.section-padding{padding:96px 0}
.soft-bg{background:linear-gradient(180deg,rgba(238,243,250,.75),rgba(247,248,251,.8))}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.site-header{
    position:sticky;
    top:0;
    z-index:20;
    background:rgba(247,248,251,.86);
    backdrop-filter:blur(22px);
    border-bottom:1px solid rgba(223,230,239,.72);
}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:18px 0 12px}
.brand-logo,.footer-logo{display:inline-flex;align-items:center}
.brand-logo img,.footer-logo img{width:150px;height:auto}
.main-nav{display:flex;align-items:center;justify-content:center;gap:6px;flex:1}
.main-nav a{
    padding:10px 14px;
    border-radius:999px;
    color:var(--muted);
    transition:background .2s ease,color .2s ease,transform .2s ease;
}
.main-nav a:hover,.main-nav a.active{background:var(--surface);color:var(--ink);box-shadow:0 10px 30px rgba(15,23,42,.06);transform:translateY(-1px)}
.header-cta,.btn{
    display:inline-flex;
    align-items:center;
    justify-content:center;
    border-radius:999px;
    min-height:44px;
    padding:0 20px;
    border:1px solid var(--line);
    transition:transform .2s ease,box-shadow .2s ease,background .2s ease;
}
.header-cta{background:var(--ink);color:#fff;border-color:var(--ink)}
.header-cta:hover,.btn:hover{transform:translateY(-2px);box-shadow:0 14px 32px rgba(15,23,42,.12)}
.search-row{display:grid;grid-template-columns:1fr auto minmax(220px,auto);gap:12px;align-items:center;padding:0 0 16px}
.search-row input{
    width:100%;
    border:1px solid var(--line);
    background:var(--surface);
    color:var(--ink);
    border-radius:999px;
    padding:13px 18px;
    outline:none;
    box-shadow:0 12px 32px rgba(15,23,42,.04);
}
.search-row input:focus{border-color:var(--accent);box-shadow:0 0 0 5px var(--accent-soft)}
.search-row button{
    border:0;
    border-radius:999px;
    background:var(--surface);
    color:var(--ink);
    padding:13px 20px;
    cursor:pointer;
}
#search-hint{font-size:14px;color:var(--muted);text-align:right}
.hero{overflow:hidden;background:radial-gradient(circle at 85% 8%,rgba(37,99,235,.14),transparent 34%),linear-gradient(180deg,#fff,var(--bg))}
.hero-grid{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(380px,.95fr);gap:64px;align-items:center}
.eyebrow{margin:0 0 12px;color:var(--accent);font-size:13px;letter-spacing:.12em;text-transform:uppercase;font-weight:700}
h1,h2,h3{line-height:1.18;margin:0;color:var(--ink);letter-spacing:-.035em}
h1{font-size:clamp(42px,6vw,76px);max-width:820px}
h2{font-size:clamp(30px,4vw,48px)}
h3{font-size:22px}
.hero-subtitle{font-size:18px;color:var(--muted);max-width:680px;margin:24px 0 0}
.hero-actions{display:flex;flex-wrap:wrap;gap:14px;margin:34px 0}
.btn.primary{background:var(--ink);color:#fff;border-color:var(--ink)}
.btn.ghost{background:rgba(255,255,255,.74);color:var(--ink)}
.hero-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:36px 0 0;padding:0}
.hero-stats div,.metric-grid div{
    background:rgba(255,255,255,.78);
    border:1px solid rgba(223,230,239,.9);
    border-radius:24px;
    padding:18px;
    box-shadow:0 18px 50px rgba(15,23,42,.05);
}
.hero-stats dt,.metric-grid span{color:var(--muted);font-size:14px}
.hero-stats dd,.metric-grid strong{margin:4px 0 0;font-size:28px;font-weight:800;letter-spacing:-.04em}
.hero-visual{margin:0;border-radius:36px;padding:14px;background:rgba(255,255,255,.68);border:1px solid rgba(255,255,255,.85);box-shadow:var(--shadow)}
.hero-visual img{border-radius:28px;aspect-ratio:16/9;object-fit:cover}
.hero-visual figcaption,.image-desc{font-size:12px;color:var(--muted);margin:12px 8px 2px}
.split-section{display:grid;grid-template-columns:.85fr 1.15fr;gap:60px;align-items:start}
.prose-card,.join-card{
    border:1px solid var(--line);
    border-radius:var(--radius);
    background:var(--surface);
    padding:34px;
    box-shadow:var(--shadow);
}
.prose-card p{margin:0 0 16px;color:var(--muted)}
.prose-card p:last-child{margin-bottom:0}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:36px;margin-bottom:34px}
.section-head h2{max-width:720px}
.section-head p:not(.eyebrow){max-width:480px;margin:0;color:var(--muted)}
.section-head.compact{display:block;text-align:center}
.card-grid{display:grid;gap:24px}
.video-grid{grid-template-columns:repeat(3,1fr)}
.video-card{
    background:var(--surface);
    border:1px solid var(--line);
    border-radius:30px;
    overflow:hidden;
    box-shadow:0 20px 70px rgba(15,23,42,.07);
    transition:transform .24s ease,box-shadow .24s ease,border-color .24s ease;
}
.video-card:hover{transform:translateY(-6px);box-shadow:0 30px 90px rgba(15,23,42,.12);border-color:#c8d5e6}
.video-media{position:relative;aspect-ratio:16/9;background:#e8eef7;overflow:hidden}
.video-media img,.video-media video{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;transition:opacity .24s ease,transform .4s ease}
.video-media video{opacity:0}
.video-card.is-playing .video-media video{opacity:1}
.video-card.is-playing .video-media img{opacity:0}
.video-card:hover .video-media img{transform:scale(1.025)}
.play-overlay{
    position:absolute;
    left:50%;top:50%;
    transform:translate(-50%,-50%) scale(.92);
    width:62px;height:62px;
    border-radius:999px;
    border:1px solid rgba(255,255,255,.7);
    background:rgba(255,255,255,.86);
    color:var(--accent);
    cursor:pointer;
    opacity:0;
    transition:opacity .2s ease,transform .2s ease;
    box-shadow:0 18px 40px rgba(15,23,42,.18);
}
.video-card:hover .play-overlay,.video-card:focus-within .play-overlay{opacity:1;transform:translate(-50%,-50%) scale(1)}
.video-body{padding:24px}
.video-body p{color:var(--muted);margin:12px 0 0}
.tag-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}
.tag-row span,.board-card span{
    display:inline-flex;
    align-items:center;
    border-radius:999px;
    background:var(--accent-soft);
    color:#1d4ed8;
    padding:6px 10px;
    font-size:12px;
    font-weight:700;
}
.stats{display:flex;flex-wrap:wrap;gap:12px;margin-top:16px;color:var(--muted);font-size:13px}
.board-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.board-card{
    min-height:230px;
    border:1px solid var(--line);
    border-radius:30px;
    background:var(--surface);
    padding:28px;
    transition:transform .22s ease,box-shadow .22s ease;
}
.board-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.board-card h3{margin-top:20px}
.board-card p{color:var(--muted)}
.board-card strong{display:block;margin-top:22px;color:var(--accent)}
.metric-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;text-align:center}
.metric-grid strong{display:block;font-size:40px}
.review-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.review-card{
    background:var(--surface);
    border:1px solid var(--line);
    border-radius:28px;
    padding:28px;
}
.review-card p{color:var(--muted);margin:0 0 24px}
.review-card span{color:var(--muted);font-size:14px}
.faq-list{display:grid;gap:12px;max-width:920px}
details{
    background:var(--surface);
    border:1px solid var(--line);
    border-radius:22px;
    padding:18px 22px;
}
summary{cursor:pointer;font-weight:800;color:var(--ink)}
details p{color:var(--muted);margin:12px 0 2px}
.join-section{background:linear-gradient(135deg,#0f172a,#1d4ed8);color:#fff}
.join-section h2,.join-section .eyebrow{color:#fff}
.join-section p{color:rgba(255,255,255,.74)}
.join-card{display:grid;grid-template-columns:1.1fr .9fr;gap:38px;align-items:center;background:rgba(255,255,255,.12);border-color:rgba(255,255,255,.2);box-shadow:none}
.join-form{display:grid;gap:14px}
.join-form label{display:grid;gap:8px;color:rgba(255,255,255,.78)}
.join-form input{border:1px solid rgba(255,255,255,.24);border-radius:18px;background:rgba(255,255,255,.12);color:#fff;padding:14px 16px;outline:none}
.join-form input::placeholder{color:rgba(255,255,255,.55)}
.site-footer{padding:72px 0 26px;background:#fff;border-top:1px solid var(--line)}
.footer-grid{display:grid;grid-template-columns:1.2fr .8fr .8fr;gap:44px}
.site-footer p{color:var(--muted);max-width:520px}
.site-footer nav{display:grid;gap:10px;align-content:start}
.site-footer h2{font-size:16px;margin-bottom:8px}
.site-footer nav a{color:var(--muted)}
.site-footer nav a:hover{color:var(--accent)}
.share-list{display:flex;flex-wrap:wrap;gap:10px}
.share-btn{border:1px solid var(--line);background:var(--surface);border-radius:999px;padding:8px 12px;cursor:pointer;color:var(--muted)}
.share-btn:hover{color:var(--accent);border-color:#bfdbfe;background:#eff6ff}
.footer-bottom{border-top:1px solid var(--line);margin-top:44px;padding-top:22px;display:flex;justify-content:space-between;gap:18px;color:var(--muted);font-size:14px}
.page-hero{background:linear-gradient(180deg,#fff,var(--bg));padding:88px 0 62px}
.page-hero .crumb{color:var(--muted);font-size:14px;margin:0 0 16px}
.page-hero p:last-child{max-width:780px;color:var(--muted);font-size:18px}
.content-grid{display:grid;grid-template-columns:2fr 1fr;gap:26px;align-items:start}
.content-card,.side-card{
    background:var(--surface);
    border:1px solid var(--line);
    border-radius:28px;
    padding:30px;
    box-shadow:0 18px 55px rgba(15,23,42,.06);
}
.content-card + .content-card{margin-top:18px}
.content-card p,.side-card p{color:var(--muted)}
.side-card ul{margin:0;padding-left:20px;color:var(--muted)}
.inline-list{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}
.inline-list a{border:1px solid var(--line);border-radius:999px;padding:8px 12px;color:var(--muted);background:#fff}
.notice{border-left:4px solid var(--accent);padding-left:18px;color:var(--muted)}
@media (max-width:960px){
    .header-inner{flex-wrap:wrap}
    .main-nav{order:3;flex-basis:100%;justify-content:flex-start;overflow:auto;padding-bottom:4px}
    .search-row{grid-template-columns:1fr auto}
    #search-hint{grid-column:1/-1;text-align:left}
    .hero-grid,.split-section,.join-card,.content-grid{grid-template-columns:1fr}
    .video-grid,.board-grid,.review-grid{grid-template-columns:repeat(2,1fr)}
    .metric-grid,.footer-grid{grid-template-columns:repeat(2,1fr)}
    .section-head{display:block}
    .section-head p:not(.eyebrow){margin-top:14px}
}
@media (max-width:640px){
    .container{width:min(100% - 24px,var(--container))}
    .section-padding{padding:66px 0}
    .header-cta{display:none}
    .search-row{grid-template-columns:1fr}
    .search-row button{width:100%}
    h1{font-size:38px}
    .hero-stats,.video-grid,.board-grid,.review-grid,.metric-grid,.footer-grid{grid-template-columns:1fr}
    .hero-copy{padding-top:14px}
    .footer-bottom{display:block}
}
.rank-row{display:grid;grid-template-columns:56px 1fr auto;gap:18px;align-items:center;padding:20px 0;border-bottom:1px solid var(--line)}
.rank-row:last-child{border-bottom:0}
.rank-row strong{font-size:28px;color:var(--accent)}
.rank-row p{margin:6px 0 0;color:var(--muted)}
.rank-row span{white-space:nowrap;color:var(--muted)}
@media (max-width:640px){.rank-row{grid-template-columns:1fr}.rank-row span{white-space:normal}}