/* 小贝网课平台介绍页 · 与主站共用配色与动效语言 */
:root{--ink:#171c18;--ink-soft:#343b35;--muted:#737a73;--bg:#f4f1e9;--surface:#fffdf8;--surface-soft:#f8f5ee;--line:rgba(23,28,24,.12);--line-strong:rgba(23,28,24,.22);--accent:#ff5a36;--accent-deep:#e74724;--lime:#d8fb72;--teal:#0d8f7c;--blue:#3977f6;--shadow:0 20px 55px rgba(23,28,24,.09);--shadow-sm:0 8px 24px rgba(23,28,24,.06);--ease:cubic-bezier(.22,1,.36,1);--spring:cubic-bezier(.16,1.2,.3,1)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:var(--bg);font-family:"Microsoft YaHei","PingFang SC",Arial,sans-serif;line-height:1.72;overflow-x:hidden}body:before{content:"";position:fixed;inset:0;pointer-events:none;background-image:linear-gradient(rgba(23,28,24,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(23,28,24,.035) 1px,transparent 1px);background-size:38px 38px;mask-image:linear-gradient(to bottom,#000,transparent 68%);z-index:-1}a{color:inherit;text-decoration:none}button,a{-webkit-tap-highlight-color:transparent}.shell{width:min(1160px,calc(100% - 36px));margin:0 auto}
.site-head{position:sticky;top:0;z-index:30;background:rgba(244,241,233,.82);backdrop-filter:blur(18px);border-bottom:1px solid var(--line);animation:head-in .55s var(--ease) both}.head-inner{min-height:74px;display:flex;align-items:center;justify-content:space-between;gap:22px}.brand{display:flex;align-items:center;gap:12px;font-weight:900;letter-spacing:-.03em}.brand-mark{width:42px;height:42px;display:grid;place-items:center;border-radius:13px;background:var(--ink);color:var(--lime);font-size:20px;box-shadow:0 10px 22px rgba(23,28,24,.18);transition:transform .35s var(--spring)}.brand:hover .brand-mark{transform:rotate(-6deg) scale(1.05)}.brand small{display:block;color:var(--muted);font-size:11px;font-weight:600;letter-spacing:.08em}.head-nav{display:flex;align-items:center;gap:24px;font-size:14px;font-weight:750;color:var(--ink-soft)}.head-nav a{position:relative;padding:8px 0}.head-nav a:after{content:"";position:absolute;left:0;right:100%;bottom:2px;height:2px;background:var(--accent);transition:right .28s var(--ease)}.head-nav a:hover:after{right:0}.head-action{padding:10px 16px;border-radius:999px;background:var(--ink);color:#fff;font-size:13px;font-weight:800;box-shadow:0 8px 18px rgba(23,28,24,.14);transition:transform .3s var(--spring),box-shadow .3s}.head-action:hover{transform:translateY(-2px);box-shadow:0 12px 24px rgba(23,28,24,.2)}
.hero{padding:54px 0 38px}.hero-card{position:relative;isolation:isolate;overflow:hidden;min-height:390px;padding:58px;border-radius:34px;color:#fff;background:radial-gradient(circle at 84% 2%,rgba(255,90,54,.46),transparent 23rem),radial-gradient(circle at 100% 100%,rgba(216,251,114,.12),transparent 22rem),linear-gradient(135deg,#141916 0%,#202a23 58%,#111512 100%);box-shadow:0 28px 80px rgba(23,28,24,.2);animation:hero-in .8s var(--ease) both}.hero-card:before{content:"";position:absolute;inset:0;z-index:-1;opacity:.52;background-image:linear-gradient(rgba(255,255,255,.055) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.055) 1px,transparent 1px);background-size:36px 36px;mask-image:linear-gradient(90deg,transparent 2%,#000 52%,#000)}.hero-card:after{content:"";position:absolute;z-index:-1;right:-95px;top:-130px;width:390px;height:390px;border:1px solid rgba(255,255,255,.18);border-radius:50%;box-shadow:0 0 0 38px rgba(255,255,255,.026),0 0 0 82px rgba(255,255,255,.018),0 0 0 126px rgba(255,255,255,.012);animation:orbit 14s linear infinite}.hero-topline{display:flex;align-items:center;gap:10px;color:rgba(255,255,255,.58);font-size:12px;font-weight:800;letter-spacing:.13em;text-transform:uppercase}.hero-topline:before{content:"";width:28px;height:2px;background:var(--accent)}.hero h1{max-width:810px;margin:18px 0;font-size:clamp(38px,6vw,72px);line-height:1.05;letter-spacing:-.065em;font-weight:950;text-wrap:balance}.hero p{max-width:700px;margin:0;color:rgba(255,255,255,.68);font-size:17px;line-height:1.8}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:48px;padding:0 21px;border-radius:14px;font-size:14px;font-weight:850;transition:transform .3s var(--spring),box-shadow .3s}.btn:hover{transform:translateY(-3px)}.btn-primary{background:var(--accent);color:#fff;box-shadow:0 12px 26px rgba(255,90,54,.25)}.btn-light{background:rgba(255,255,255,.09);color:#fff;border:1px solid rgba(255,255,255,.18);backdrop-filter:blur(10px)}.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:28px}.chip{padding:7px 12px;border-radius:999px;border:1px solid rgba(255,255,255,.13);background:rgba(255,255,255,.06);color:rgba(255,255,255,.68);font-size:12px;font-weight:650}
main{padding-bottom:50px}.section{padding:36px 0}.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:22px;margin-bottom:22px}.eyebrow{color:var(--accent);font-size:12px;font-weight:900;letter-spacing:.12em;text-transform:uppercase}.section h2{margin:7px 0 0;font-size:clamp(28px,4vw,42px);line-height:1.16;letter-spacing:-.045em}.section-intro{max-width:680px;color:var(--muted);font-size:15px}.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.panel{background:var(--surface);border:1px solid var(--line);border-radius:22px;padding:25px;box-shadow:var(--shadow-sm);transition:transform .36s var(--ease),box-shadow .36s,border-color .36s}.panel:hover{transform:translateY(-5px);border-color:rgba(255,90,54,.28);box-shadow:var(--shadow)}.num{width:36px;height:36px;display:grid;place-items:center;border-radius:11px;background:var(--surface-soft);color:var(--accent);font-weight:950;font-size:13px;border:1px solid var(--line)}.panel h3{margin:16px 0 8px;font-size:19px;letter-spacing:-.025em}.panel p{margin:0;color:var(--muted);font-size:14px;line-height:1.75}.list-panel{padding:28px}.check-list{margin:16px 0 0;padding:0;list-style:none;display:grid;gap:11px}.check-list li{position:relative;padding-left:27px;color:var(--ink-soft);font-size:14px}.check-list li:before{content:"";position:absolute;left:0;top:.55em;width:13px;height:13px;border-radius:50%;background:var(--lime);box-shadow:inset 0 0 0 4px var(--surface)}
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;counter-reset:step}.step{position:relative;padding:24px;border-radius:20px;background:var(--surface);border:1px solid var(--line);overflow:hidden}.step:before{counter-increment:step;content:"0" counter(step);position:absolute;right:16px;top:9px;color:rgba(23,28,24,.055);font-size:54px;font-weight:950;line-height:1}.step h3{position:relative;margin:0 0 8px;font-size:17px}.step p{position:relative;margin:0;color:var(--muted);font-size:13px;line-height:1.7}.faq-list{display:grid;gap:11px}.faq{background:var(--surface);border:1px solid var(--line);border-radius:18px;overflow:hidden}.faq summary{list-style:none;cursor:pointer;padding:18px 21px;font-weight:850;display:flex;justify-content:space-between;gap:16px}.faq summary::-webkit-details-marker{display:none}.faq summary:after{content:"+";color:var(--accent);font-size:22px;line-height:1;transition:transform .25s var(--ease)}.faq[open] summary:after{transform:rotate(45deg)}.faq-body{padding:0 21px 20px;color:var(--muted);font-size:14px;border-top:1px solid var(--line)}
.platform-links{display:grid;grid-template-columns:repeat(5,1fr);gap:10px}.platform-link{background:var(--surface);border:1px solid var(--line);border-radius:17px;padding:16px;transition:transform .3s var(--spring),border-color .3s}.platform-link:hover{transform:translateY(-4px);border-color:var(--accent)}.platform-link b{display:block;font-size:14px}.platform-link span{display:block;color:var(--muted);font-size:11px;margin-top:4px}.cta-band{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:32px 36px;border-radius:26px;background:var(--ink);color:#fff;box-shadow:0 22px 50px rgba(23,28,24,.18)}.cta-band h2{margin:0 0 7px;font-size:28px;letter-spacing:-.04em}.cta-band p{margin:0;color:rgba(255,255,255,.62);font-size:14px}.cta-band .btn-primary{flex:0 0 auto}.footer{padding:28px 0 42px;border-top:1px solid var(--line);color:var(--muted);font-size:13px}.footer-inner{display:flex;justify-content:space-between;gap:18px;flex-wrap:wrap}.footer a:hover{color:var(--accent)}
.js [data-reveal]{opacity:0;transform:translateY(22px);transition:opacity .7s var(--ease),transform .7s var(--ease)}.js [data-reveal].is-visible{opacity:1;transform:none}.js [data-reveal][data-delay="1"]{transition-delay:.08s}.js [data-reveal][data-delay="2"]{transition-delay:.16s}.js [data-reveal][data-delay="3"]{transition-delay:.24s}
@keyframes head-in{from{opacity:0;transform:translateY(-12px)}to{opacity:1;transform:none}}@keyframes hero-in{from{opacity:0;transform:translateY(22px) scale(.985)}to{opacity:1;transform:none}}@keyframes orbit{to{transform:rotate(360deg)}}
@media(max-width:900px){.head-nav{display:none}.hero-card{padding:40px 28px;min-height:0}.grid{grid-template-columns:1fr 1fr}.steps{grid-template-columns:1fr 1fr}.platform-links{grid-template-columns:1fr 1fr}.section-head{display:block}.section-intro{margin-top:12px}.cta-band{align-items:flex-start;flex-direction:column}}
@media(max-width:620px){.shell{width:min(100% - 24px,1160px)}.head-inner{min-height:64px}.head-action{padding:9px 12px;font-size:12px}.hero{padding:28px 0 22px}.hero-card{padding:32px 22px;border-radius:26px}.hero h1{font-size:42px}.hero p{font-size:15px}.hero-actions .btn{width:100%}.chips{gap:6px}.section{padding:25px 0}.grid,.steps,.platform-links{grid-template-columns:1fr}.panel,.list-panel,.step{padding:21px}.cta-band{padding:25px 22px;border-radius:22px}.cta-band .btn{width:100%}.footer-inner{display:block}.footer-inner span{display:block;margin-top:6px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important}.js [data-reveal]{opacity:1;transform:none}}