*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:26px}body{margin:0;color:#213a32;background:#f4f4ef;font:16px/1.6 system-ui,-apple-system,"Microsoft YaHei",sans-serif}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit;cursor:pointer}a{color:inherit}button:focus-visible,a:focus-visible{outline:3px solid #c18130;outline-offset:4px}button:disabled{opacity:.45;cursor:default}[hidden]{display:none!important}.skip{position:fixed;top:-80px;left:10px;background:white;padding:12px;z-index:10}.skip:focus{top:10px}.header{border-bottom:1px solid #dce1d9;background:#fafbf6}.header-inner{max-width:1200px;margin:auto;padding:22px 32px;display:flex;justify-content:space-between;align-items:center;gap:20px}.brand{text-decoration:none;display:flex;align-items:center;gap:11px;font-size:25px;line-height:1.1;font-weight:760;letter-spacing:.06em}.brand svg{width:37px;fill:none;stroke:#24684c;stroke-width:2.2}.brand small{display:block;margin-top:6px;font-size:12px;letter-spacing:.19em;font-weight:500;color:#66786b}nav{display:flex;gap:26px}nav a{font-size:14px;text-decoration:none;color:#426050}nav a:hover{text-decoration:underline}main{max-width:1200px;margin:auto;padding:40px 32px 44px}.eyebrow{font-size:12px;letter-spacing:.13em;color:#527361;font-weight:650}.intro h1{font-size:38px;line-height:1.3;letter-spacing:-.04em;font-weight:700;margin:12px 0}.lead{font-size:17px;color:#617364;margin:0}.badges{display:flex;gap:8px;flex-wrap:wrap;margin:20px 0 30px}.badges span{border:1px solid #d3ddd1;padding:4px 11px;font-size:12px;border-radius:4px;color:#50674f;background:#fbfcf7}.mobile-break{display:none}.lesson-layout{display:grid;grid-template-columns:minmax(280px,440px) minmax(300px,1fr);gap:42px;align-items:start}.watch{min-width:0}.player-shell{position:relative;width:100%;aspect-ratio:9/16;background:#14221c;overflow:hidden;border-radius:10px;box-shadow:0 12px 35px #1b352517}.player-shell video{display:block;width:100%;height:100%;object-fit:contain}.play-cover{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;border:0;color:white;background:linear-gradient(transparent 30%,#0d271455);gap:18px}.play-disc{display:grid;place-items:center;width:72px;height:72px;padding-left:5px;border-radius:50%;background:#f9fff5e8;color:#204d36;font-size:26px;box-shadow:0 5px 30px #0003}.play-cover:hover .play-disc{background:#fff;transform:scale(1.04)}.play-label{font-size:20px;font-weight:650;text-shadow:0 1px 10px #000}.play-label small{display:block;font-size:12px;font-weight:500;margin-top:6px}.video-error{position:absolute;inset:auto 12px 60px;padding:18px;border-radius:8px;background:#123125f5;color:#fff;font-size:14px}.video-error p{margin:0 0 12px}.now{display:grid;gap:4px;margin-top:20px;min-height:55px}.now-tag{font-size:12px;color:#6b7a6a;letter-spacing:.08em}.now strong{font-size:16px}.player-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}.button{border:1px solid #ccd8cc;color:#30583e;background:#fff;padding:8px 12px;font-size:13px;border-radius:5px;min-height:40px}.button:hover{background:#e8eee2}.button.light{background:#fff}.resume{width:100%;text-align:left;margin-top:15px;padding:12px 15px;background:#e5ecdb;color:#30553c;border:0;border-radius:5px;font-size:14px}.play-hint{font-size:12px;color:#6b7a6a;margin:13px 0 0;line-height:1.7}.status{font-size:13px;color:#2b6545;min-height:21px;margin:5px 0}.chapter-panel{background:#fdfef9;border:1px solid #dbe3d6;border-radius:10px;overflow:hidden}.panel-heading{display:flex;justify-content:space-between;align-items:center;padding:25px 26px 20px;border-bottom:1px solid #e3e8dd}.panel-heading h2{font-size:24px;line-height:1.3;margin:6px 0 0}.count{border:1px solid #dce4d3;padding:5px 10px;border-radius:5px;font-size:12px;color:#66785f}.chapter-list{max-height:792px;overflow:auto;overscroll-behavior:contain;scrollbar-width:thin;scrollbar-color:#c4d0bf transparent;padding:8px 12px 14px}.chapter-group{padding:14px 14px 9px;font-size:12px;letter-spacing:.04em;font-weight:600;color:#7b886e}.chapter{display:grid;grid-template-columns:25px 1fr auto;gap:12px;align-items:center;width:100%;text-align:left;border:1px solid transparent;border-radius:5px;background:transparent;color:#324837;padding:11px 13px;font-size:14px;line-height:1.5;min-height:49px}.chapter:hover{background:#eef3e7}.chapter.active{background:#e4edde;border-color:#d4e1c8;color:#224b31}.chapter-num{font-size:12px;color:#87937b;font-variant-numeric:tabular-nums}.chapter.active .chapter-num{color:#3b7546;font-weight:750}.chapter-title{min-width:0}.chapter time{font-size:12px;color:#7a8973;font-variant-numeric:tabular-nums}.loading{padding:20px;font-size:14px}.resources{margin-top:52px;padding-top:35px;border-top:1px solid #d4dece}.resource-intro h2{font-size:26px;margin:8px 0}.resource-intro p{color:#6b7b64;font-size:14px;margin:0 0 22px}.resource-grid{display:grid;grid-template-columns:1.2fr 1fr 1fr;gap:15px}.resource-card{display:flex;gap:14px;align-items:center;text-decoration:none;border:1px solid #d4dece;background:#fbfcf7;border-radius:7px;padding:20px 16px;min-width:0}.resource-card:hover{border-color:#74966b;background:#fff}.resource-card.featured{background:#e9efdf}.file-icon{display:grid;place-items:center;width:38px;height:46px;background:#fff;border:1px solid #d1ddc7;border-radius:3px;color:#61834e;font-size:11px;font-weight:750;flex-shrink:0}.resource-card strong{font-size:14px;display:block}.resource-card small{font-size:12px;color:#77836e;display:block;margin-top:3px}.arrow{margin-left:auto;color:#4e7142}.course-note{margin:30px 0 0;padding-left:15px;border-left:2px solid #c6d4bc;max-width:850px;font-size:12px;color:#7b8773}.course-note strong{font-weight:650;color:#596c4e}.course-note p{margin:4px 0;line-height:1.8}footer{max-width:1200px;display:flex;justify-content:space-between;gap:15px;margin:auto;padding:24px 32px 32px;border-top:1px solid #dce2d5;color:#86917d;font-size:12px}@media(min-width:1100px){.player-shell{max-height:710px;width:auto;max-width:100%;margin:0 auto}.watch{max-width:440px}.chapter-list{max-height:771px}}@media(max-width:800px){.header-inner{padding:17px 22px}.brand{font-size:21px}.brand svg{width:32px}.brand small{font-size:10px}nav{gap:16px}nav a{font-size:12px}main{padding:28px 22px}.intro h1{font-size:30px}.lesson-layout{gap:24px;grid-template-columns:minmax(240px,.9fr) 1.1fr}.panel-heading{padding:20px}.chapter{gap:8px;padding:10px 7px;font-size:13px;grid-template-columns:21px 1fr auto}.chapter-list{padding:7px;max-height:690px}.resource-grid{grid-template-columns:1fr}.resource-card{padding:16px 20px}}@media(max-width:600px){.header-inner{padding:16px 18px}main{padding:26px 18px 30px}.intro h1{font-size:29px;line-height:1.35;margin:10px 0}.mobile-break{display:block}.lead{font-size:14px}.badges{margin:17px 0 23px;gap:6px}.badges span{padding:3px 8px;font-size:11px}.lesson-layout{display:block}.watch{max-width:100%}.player-shell{max-height:76svh;max-width:100%;width:auto;margin:0 auto;min-height:330px}.now{margin-top:16px}.player-actions{gap:7px}.button{padding:8px 11px}.chapter-panel{margin-top:25px}.chapter-list{max-height:580px;padding:8px 10px}.chapter{grid-template-columns:24px 1fr auto;padding:12px 10px;gap:10px;font-size:14px}.panel-heading{padding:20px 22px}.resources{margin-top:30px;padding-top:26px}.resource-intro h2{font-size:23px}footer{padding:22px 18px;flex-direction:column;gap:5px}.course-note{margin-top:24px}.play-hint{font-size:12px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.play-cover:hover .play-disc{transform:none}}