.tutorial-intro{padding:146px 0 65px;background:#081728}.tutorial-intro h1{font-size:52px;line-height:1.2;letter-spacing:-.03em;margin:20px 0}.tutorial-intro p{max-width:700px;color:#adc1d1;font-size:16px;line-height:1.9}.tutorial-summary{display:flex;flex-wrap:wrap;gap:12px 30px;margin-top:30px;color:#77c7d6;font-size:12px}.tutorial-section{padding:52px 0 84px;background:#f1f5f8}.tutorial-layout{display:grid;grid-template-columns:minmax(0,1fr) 350px;gap:30px;align-items:start}.tutorial-main{min-width:0}.tutorial-heading{display:flex;gap:15px;align-items:center;margin-bottom:22px}.tutorial-number{display:grid;place-items:center;width:48px;height:48px;border:1px solid #c5dce7;border-radius:12px;color:#1786a6;font-size:17px;font-weight:700;background:#e6f3f8}.tutorial-heading p{margin:0 0 5px;font-size:11px;color:#638298}.tutorial-heading h2{margin:0;font-size:25px;line-height:1.35}.tutorial-screen{position:relative;overflow:hidden;background:#081728;border-radius:12px;aspect-ratio:16/9;box-shadow:0 16px 40px #0b263c1a}.tutorial-screen video{display:block;width:100%;height:100%;object-fit:contain}.tutorial-description{line-height:1.9;font-size:14px;color:#526d81;margin:20px 0 13px}.tutorial-meta{display:flex;flex-wrap:wrap;gap:10px 22px;color:#72899a;font-size:11px}.tutorial-meta a{margin-left:auto;color:#1786a6}.tutorial-pager{display:flex;justify-content:space-between;align-items:center;gap:10px;margin:23px 0 30px;padding:16px 0;border-top:1px solid #d9e4eb;border-bottom:1px solid #d9e4eb}.tutorial-pager button,.tutorial-video-error button{border:1px solid #b9ceda;border-radius:7px;background:white;padding:10px 14px;font-size:12px;color:#28485d}.tutorial-pager button:disabled{opacity:.4;cursor:default}.tutorial-pager span{font-size:11px;color:#718899;text-align:center}.tutorial-chapters h3{font-size:18px;margin:0 0 6px}.tutorial-chapters p{font-size:12px;color:#718899;margin:0 0 16px}#chapter-list{display:grid;grid-template-columns:1fr 1fr;gap:9px}#chapter-list button{display:flex;gap:12px;align-items:center;text-align:left;background:white;border:1px solid #d5e2ea;border-radius:8px;padding:14px 15px;min-height:52px}#chapter-list span{font-size:11px;color:#1786a6;font-variant-numeric:tabular-nums}#chapter-list strong{font-size:12px;font-weight:500;color:#345165}#chapter-list i{margin-left:auto;color:#7c98a9;font-style:normal}.scope-explainer{margin-top:30px;padding:25px;border:1px solid #b9dce4;border-radius:12px;background:#eaf7f8}.scope-explainer>span{font-size:11px;color:#18839d}.scope-explainer h3{font-size:20px;margin:13px 0}.scope-explainer p{font-size:13px;line-height:1.9;color:#526d81}.scope-explainer a{display:inline-block;margin-top:10px;font-size:12px;color:#1786a6;font-weight:600}.tutorial-note{font-size:11px;color:#8296a4;line-height:1.9;margin:21px 0 0}.tutorial-catalog{padding:20px;border:1px solid #d7e2e9;border-radius:12px;background:white;position:sticky;top:95px}.catalog-heading{display:flex;justify-content:space-between;align-items:center;margin-bottom:17px}.catalog-heading h2{font-size:17px;margin:0}.catalog-heading span{font-size:10px;color:#758d9d}.tutorial-search input{width:100%;padding:11px 13px;border:1px solid #d5e2ea;border-radius:7px;background:#f7fafc;color:#28485d;font-size:12px}.tutorial-filters{display:flex;flex-wrap:wrap;gap:6px;margin:13px 0 15px}.tutorial-filters button{padding:6px 8px;border-radius:5px;border:1px solid #dde7ed;background:white;font-size:10px;color:#748c9c}.tutorial-filters button[aria-pressed=true]{background:#e9f5fa;border-color:#b3d7e5;color:#1683a3}.catalog-list{display:grid;gap:6px;max-height:580px;overflow:auto;padding-right:3px}.catalog-item{display:flex;align-items:center;gap:11px;padding:12px 9px;border:1px solid transparent;border-radius:7px;background:white;text-align:left;width:100%}.catalog-item:hover,.catalog-item.selected{border-color:#c1e1ec;background:#edf8fc}.catalog-item:disabled{opacity:.55;cursor:default}.catalog-number{font-size:11px;color:#78a1b5;font-variant-numeric:tabular-nums}.catalog-copy{min-width:0;flex:1}.catalog-copy strong{display:block;font-size:12px;color:#294a60;line-height:1.55}.catalog-copy small{display:block;font-size:9px;color:#8196a5;margin-top:5px;line-height:1.5}.catalog-time{font-size:10px;white-space:nowrap;color:#6f8797;font-variant-numeric:tabular-nums}.catalog-empty{padding:24px 8px;font-size:12px;line-height:1.9;color:#758b9a}.catalog-empty button{display:block;margin-top:10px;color:#1786a6;background:none;padding:0}.tutorial-video-error{position:absolute;inset:0;display:flex;flex-direction:column;justify-content:center;align-items:center;padding:20px;background:#081728;color:white;text-align:center}.tutorial-video-error[hidden],.catalog-empty[hidden]{display:none}.tutorial-video-error p{font-size:12px;color:#adc1d1}.tutorial-video-error a{font-size:12px;color:#77c7d6;margin-top:16px}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}body[data-page=features] button:focus-visible,body[data-page=features] a:focus-visible,body[data-page=features] input:focus-visible{outline:3px solid #169fc0;outline-offset:3px}.catalog-item.selected .catalog-number{font-weight:700;color:#1683a3}@media(max-width:1100px){.tutorial-layout{grid-template-columns:minmax(0,1fr) 310px;gap:22px}.tutorial-catalog{padding:16px}.tutorial-heading h2{font-size:22px}}@media(max-width:900px){.tutorial-intro{padding:118px 0 46px}.tutorial-intro h1{font-size:43px}.tutorial-layout{grid-template-columns:1fr}.tutorial-catalog{position:static}.catalog-list{max-height:none;grid-template-columns:1fr 1fr}.tutorial-section{padding:34px 0 56px}.tutorial-catalog{order:2}}@media(max-width:560px){.tutorial-intro h1{font-size:36px}.tutorial-intro p{font-size:14px}.tutorial-summary{gap:9px 18px}.tutorial-heading h2{font-size:20px}.tutorial-number{width:40px;height:40px;flex-shrink:0}.tutorial-heading{gap:11px}.tutorial-screen{border-radius:8px}.tutorial-meta a{margin-left:0}.tutorial-pager span{max-width:110px;line-height:1.5}.tutorial-pager button{padding:10px;font-size:11px}#chapter-list,.catalog-list{grid-template-columns:1fr}.scope-explainer{padding:20px}.scope-explainer h3{font-size:18px}.tutorial-catalog{padding:17px}.tutorial-video-error strong{font-size:14px}.tutorial-video-error p{font-size:10px;margin:5px 0}.tutorial-video-error button{padding:6px 10px}.tutorial-video-error a{margin-top:8px;font-size:10px}}

/* 固定导航下保留标题和播放器的滚动定位空间。 */
#watch,.tutorial-heading,.tutorial-screen{scroll-margin-top:95px}