:root{
  --bg:#f7f8fa;
  --surface:#ffffff;
  --ink:#101828;
  --muted:#667085;
  --line:#e5e7eb;
  --soft:#eef2f7;
  --brand:#111827;
  --brand-2:#475467;
  --accent:#64748b;
  --radius:28px;
  --shadow:0 24px 80px rgba(15,23,42,.08);
  --shadow-soft:0 14px 40px rgba(15,23,42,.06);
  --max:1180px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:radial-gradient(circle at top left,rgba(226,232,240,.85),transparent 34rem),var(--bg);
  color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Arial,sans-serif;
  line-height:1.72;
  text-rendering:optimizeLegibility;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block;height:auto}
button,input,textarea{font:inherit}
.container{width:min(var(--max),calc(100% - 40px));margin:0 auto}
.site-header{position:sticky;top:0;z-index:20;background:rgba(247,248,250,.82);backdrop-filter:blur(20px);border-bottom:1px solid rgba(229,231,235,.78)}
.navbar{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:18px 0}
.logo{display:inline-flex;align-items:center;gap:12px;font-weight:800;letter-spacing:-.03em}
.logo-mark{display:grid;place-items:center;width:44px;height:44px;border-radius:16px;background:#111827;color:#fff;box-shadow:0 12px 34px rgba(17,24,39,.16)}
.logo-text{display:flex;flex-direction:column;line-height:1.12}
.logo-text small{font-size:12px;color:var(--muted);font-weight:600;letter-spacing:0}
.nav-links{display:flex;align-items:center;gap:4px;padding:6px;border:1px solid rgba(229,231,235,.9);border-radius:999px;background:rgba(255,255,255,.72)}
.nav-links a{padding:10px 15px;border-radius:999px;color:#344054;font-size:14px;font-weight:650;transition:background .2s ease,color .2s ease,transform .2s ease}
.nav-links a:hover,.nav-links a[aria-current="page"]{background:#111827;color:#fff;transform:translateY(-1px)}
.header-cta{display:inline-flex;align-items:center;gap:8px;padding:12px 16px;border-radius:999px;background:#fff;border:1px solid var(--line);box-shadow:var(--shadow-soft);font-weight:700;color:#111827}
.search-strip{padding:0 0 18px}
.search-shell{display:flex;align-items:center;gap:12px;border:1px solid rgba(229,231,235,.96);background:rgba(255,255,255,.82);box-shadow:0 18px 60px rgba(15,23,42,.05);border-radius:999px;padding:9px 9px 9px 18px}
.search-shell input{width:100%;border:0;outline:0;background:transparent;color:#111827;min-height:42px}
.search-shell button{border:0;white-space:nowrap;border-radius:999px;background:#111827;color:#fff;padding:11px 18px;font-weight:750;cursor:pointer}
.search-hint{font-size:13px;color:var(--muted);padding:8px 18px 0;min-height:26px}
.hero{padding:76px 0 56px}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center}
.eyebrow{display:inline-flex;align-items:center;gap:8px;border:1px solid var(--line);border-radius:999px;padding:8px 13px;background:rgba(255,255,255,.76);color:#475467;font-size:13px;font-weight:700}
.hero h1,.page-hero h1{font-size:clamp(42px,7vw,82px);line-height:.98;letter-spacing:-.075em;margin:22px 0 24px}
.hero p,.page-hero p{font-size:18px;color:var(--muted);max-width:690px;margin:0 0 30px}
.actions{display:flex;gap:14px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;justify-content:center;border-radius:999px;padding:14px 20px;font-weight:800;transition:transform .2s ease,box-shadow .2s ease,background .2s ease;border:1px solid transparent}
.btn:hover{transform:translateY(-2px)}
.btn-primary{background:#111827;color:#fff;box-shadow:0 20px 60px rgba(17,24,39,.18)}
.btn-secondary{background:#fff;color:#111827;border-color:var(--line)}
.hero-panel{position:relative;border:1px solid rgba(229,231,235,.95);background:linear-gradient(180deg,rgba(255,255,255,.92),rgba(255,255,255,.66));border-radius:44px;padding:18px;box-shadow:var(--shadow);overflow:hidden}
.hero-panel:before{content:"";position:absolute;inset:-30% -20% auto auto;width:360px;height:360px;background:radial-gradient(circle,rgba(148,163,184,.28),transparent 66%)}
.video-card-large{position:relative;border-radius:32px;overflow:hidden;background:#111827;isolation:isolate;min-height:420px}
.video-card-large img{width:100%;height:420px;object-fit:cover;opacity:.9;transition:transform .55s ease,opacity .55s ease}
.video-card-large:hover img{transform:scale(1.04);opacity:.78}
.play-float{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%) scale(.94);width:76px;height:76px;border-radius:50%;display:grid;place-items:center;background:rgba(255,255,255,.92);box-shadow:0 24px 70px rgba(0,0,0,.24);opacity:.96;transition:transform .24s ease,opacity .24s ease}
.video-card-large:hover .play-float,.video-card:hover .play-float{transform:translate(-50%,-50%) scale(1.04);opacity:1}
.play-float:after{content:"";width:0;height:0;border-top:13px solid transparent;border-bottom:13px solid transparent;border-left:20px solid #111827;margin-left:5px}
.video-meta{position:absolute;left:22px;right:22px;bottom:22px;padding:18px;border-radius:24px;background:rgba(255,255,255,.88);backdrop-filter:blur(18px)}
.video-meta strong{font-size:19px;display:block;letter-spacing:-.02em}
.video-stats{display:flex;gap:12px;flex-wrap:wrap;color:#667085;font-size:13px;margin-top:8px}
.section{padding:54px 0}
.section-heading{display:flex;justify-content:space-between;gap:24px;align-items:end;margin-bottom:24px}
.section-heading h2{font-size:clamp(28px,4vw,48px);line-height:1.05;letter-spacing:-.055em;margin:0;max-width:720px}
.section-heading p{margin:0;color:var(--muted);max-width:420px}
.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.card,.topic-card,.board-card,.review-card,.faq-item,.stat-card,.form-card{background:rgba(255,255,255,.76);border:1px solid rgba(229,231,235,.96);border-radius:var(--radius);box-shadow:0 10px 38px rgba(15,23,42,.04);transition:transform .22s ease,box-shadow .22s ease,border-color .22s ease}
.card:hover,.topic-card:hover,.board-card:hover,.review-card:hover{transform:translateY(-5px);box-shadow:var(--shadow-soft);border-color:#cbd5e1}
.card{padding:28px}.card h3{margin:12px 0 10px;font-size:22px;letter-spacing:-.035em}.card p{margin:0;color:var(--muted)}
.kicker{font-size:12px;text-transform:uppercase;letter-spacing:.16em;color:#667085;font-weight:850}
.topic-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.topic-card{overflow:hidden;position:relative}
.topic-card .thumb{position:relative;min-height:210px;background:#111827;overflow:hidden;border-radius:calc(var(--radius) - 1px) calc(var(--radius) - 1px) 0 0}
.topic-card .thumb img{width:100%;height:230px;object-fit:cover;transition:transform .45s ease,opacity .45s ease;opacity:.96}
.topic-card:hover .thumb img{transform:scale(1.05);opacity:.78}
.topic-body{padding:22px}.topic-body h3{font-size:21px;line-height:1.28;margin:8px 0 10px;letter-spacing:-.03em}.topic-body p{color:var(--muted);margin:0 0 14px}.tags{display:flex;gap:8px;flex-wrap:wrap}.tag{display:inline-flex;border-radius:999px;background:#f1f5f9;color:#475467;padding:6px 10px;font-size:12px;font-weight:750}
.board-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.board-card{padding:24px;min-height:190px}.board-icon{width:48px;height:48px;border-radius:18px;background:#111827;color:#fff;display:grid;place-items:center;font-weight:900}.board-card h3{margin:18px 0 8px;font-size:20px;letter-spacing:-.03em}.board-card p{margin:0;color:var(--muted);font-size:14px}.board-card small{display:block;margin-top:16px;color:#667085;font-weight:750}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.stat-card{padding:26px}.stat-card strong{display:block;font-size:38px;letter-spacing:-.05em;line-height:1}.stat-card span{color:var(--muted);font-weight:650}
.reviews{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.review-card{padding:24px}.review-card p{color:#475467;margin:10px 0 18px}.avatar{display:flex;align-items:center;gap:12px}.avatar span{display:grid;place-items:center;width:42px;height:42px;border-radius:50%;background:#111827;color:#fff;font-weight:850}.avatar strong{display:block}.avatar small{color:var(--muted)}
.faq-list{display:grid;gap:12px}.faq-item{padding:0;overflow:hidden}.faq-item summary{cursor:pointer;list-style:none;padding:22px 24px;font-weight:850;display:flex;align-items:center;justify-content:space-between;gap:20px}.faq-item summary::-webkit-details-marker{display:none}.faq-item summary:after{content:"+";font-size:24px;color:#667085}.faq-item[open] summary:after{content:"−"}.faq-item p{padding:0 24px 22px;margin:0;color:var(--muted)}
.join-grid{display:grid;grid-template-columns:.85fr 1.15fr;gap:22px;align-items:stretch}.form-card{padding:26px}.form-card label{display:block;font-size:13px;font-weight:800;color:#475467;margin:14px 0 7px}.form-card input,.form-card textarea{width:100%;border:1px solid var(--line);border-radius:18px;background:#fff;padding:13px 15px;outline:none;transition:border-color .2s ease,box-shadow .2s ease}.form-card input:focus,.form-card textarea:focus{border-color:#94a3b8;box-shadow:0 0 0 4px rgba(148,163,184,.16)}.form-card textarea{min-height:126px;resize:vertical}.form-note{font-size:13px;color:var(--muted)}
.page-hero{padding:70px 0 28px}.breadcrumb{display:flex;gap:8px;align-items:center;color:#667085;font-size:14px}.breadcrumb a{font-weight:800}.content-layout{display:grid;grid-template-columns:1fr 320px;gap:28px}.prose-card{background:rgba(255,255,255,.78);border:1px solid var(--line);border-radius:34px;padding:34px;box-shadow:var(--shadow-soft)}.prose-card h2{font-size:32px;letter-spacing:-.04em;line-height:1.12}.prose-card p{color:#475467}.side-card{position:sticky;top:140px;background:#111827;color:#fff;border-radius:32px;padding:26px;height:max-content}.side-card p{color:#cbd5e1}.list-lines{display:grid;gap:14px}.line-item{display:flex;justify-content:space-between;gap:18px;padding:18px;border:1px solid var(--line);border-radius:22px;background:#fff}.line-item strong{letter-spacing:-.02em}.line-item span{color:var(--muted);font-size:14px}.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:28px;background:#fff}.rank-table{width:100%;border-collapse:collapse}.rank-table th,.rank-table td{text-align:left;padding:18px;border-bottom:1px solid var(--line);white-space:nowrap}.rank-table th{color:#475467;font-size:13px}.rank-table tr:last-child td{border-bottom:0}
.share-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:10px}.share-link{border:1px solid var(--line);background:#fff;border-radius:18px;padding:12px;text-align:center;font-weight:800;color:#475467}
.site-footer{margin-top:70px;border-top:1px solid var(--line);background:rgba(255,255,255,.58)}.footer-grid{display:grid;grid-template-columns:1.2fr .8fr .8fr;gap:24px;padding:42px 0}.footer-grid h2,.footer-grid h3{margin:0 0 12px;letter-spacing:-.03em}.footer-grid p,.footer-grid a{color:#667085}.footer-links{display:grid;gap:8px}.footer-bottom{display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;border-top:1px solid var(--line);padding:18px 0;color:#667085;font-size:14px}.domain-pill{display:inline-flex;align-items:center;padding:4px 8px;border-radius:999px;background:#eef2f7;color:#344054;font-weight:800}
.reveal{opacity:0;transform:translateY(12px);transition:opacity .55s ease,transform .55s ease}.reveal.is-visible{opacity:1;transform:none}
@media (max-width:980px){.hero-grid,.join-grid,.content-layout{grid-template-columns:1fr}.board-grid,.stats{grid-template-columns:repeat(2,1fr)}.card-grid,.topic-grid,.reviews{grid-template-columns:1fr 1fr}.side-card{position:static}.nav-links{display:none}.header-cta{display:none}.share-grid{grid-template-columns:repeat(3,1fr)}}
@media (max-width:640px){.container{width:min(100% - 28px,var(--max))}.navbar{padding:14px 0}.hero{padding:52px 0 34px}.hero h1,.page-hero h1{font-size:42px}.search-shell{border-radius:24px;align-items:stretch;flex-direction:column;padding:14px}.search-shell button{width:100%}.card-grid,.topic-grid,.board-grid,.stats,.reviews,.footer-grid{grid-template-columns:1fr}.video-card-large,.video-card-large img{min-height:330px;height:330px}.section-heading{display:block}.section-heading p{margin-top:12px}.footer-bottom{display:block}.share-grid{grid-template-columns:repeat(2,1fr)}}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

.footer-logo-mark{display:inline-grid;margin-right:10px;vertical-align:middle}