:root{--ink:#16223d;--muted:#68738b;--blue:#3152e8;--line:#e4e9f2;--paper:#f5f7fc;--coral:#ef8159}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;color:var(--ink);background:#fff;font:16px/1.8 -apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif}a{color:var(--blue);text-underline-offset:4px}button,input,textarea{font:inherit}button,a{-webkit-tap-highlight-color:transparent}button{cursor:pointer}a:hover{color:#203bbb}a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid #eeab49;outline-offset:4px}.shell{width:min(1160px,calc(100% - 64px));margin:auto}.header{height:92px;display:flex;align-items:center;justify-content:space-between;gap:20px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;color:var(--ink);text-decoration:none;font-size:23px;font-weight:750}.brand img{width:35px;height:35px}.brand small{font-size:10px;letter-spacing:.12em;display:block;color:var(--muted);line-height:1.2;font-weight:500}.nav{display:flex;gap:27px;align-items:center;font-size:14px}.nav a{text-decoration:none;color:var(--muted)}.nav a[aria-current]{color:var(--blue);font-weight:650}.intro{padding:45px 0 29px;display:flex;justify-content:space-between;gap:35px;align-items:end}.eyebrow{font-size:12px;font-weight:650;letter-spacing:.13em;color:var(--blue);margin:0 0 12px}h1{font-size:clamp(32px,4.2vw,48px);line-height:1.25;letter-spacing:-.04em;margin:0 0 14px}h2{font-size:26px;line-height:1.4;letter-spacing:-.02em;margin:0 0 14px}h3{font-size:19px;line-height:1.5;margin:0 0 12px}p{margin:0 0 18px}.intro p{color:var(--muted);font-size:15px;margin:0}.intro .eyebrow{color:var(--blue);font-size:12px;margin-bottom:12px}.edition{font:11px/1.8 monospace;color:var(--muted);white-space:nowrap;text-align:right}.featured{display:grid;grid-template-columns:1.15fr 1fr;border:1px solid var(--line);border-radius:18px;overflow:hidden;background:#f7f9fd}.feature-cover{position:relative;background:#17233d;min-width:0;display:block;aspect-ratio:16/9}.feature-cover img{width:100%;height:100%;object-fit:cover;display:block}.play-dot{display:grid;place-items:center;width:58px;height:58px;border-radius:50%;background:#fff;color:#2f50e0;position:absolute;left:calc(50% - 29px);top:calc(50% - 29px);box-shadow:0 8px 25px #0002;font-size:22px}.feature-cover:hover .play-dot{transform:scale(1.07)}.cover-label{position:absolute;bottom:16px;left:20px;font-size:10px;color:#d9e2ff;background:#182344bb;padding:3px 8px;border-radius:4px}.feature-copy{padding:28px 35px;display:flex;flex-direction:column;justify-content:center}.tagline{display:flex;gap:9px;flex-wrap:wrap;align-items:center;font-size:11px;color:var(--muted);margin-bottom:13px}.pill{background:#e8edff;color:#3152c7;border-radius:5px;padding:4px 9px}.feature-copy h2{font-size:28px;margin:0 0 12px}.feature-copy p{color:var(--muted);font-size:14px;margin:0 0 18px}.actions{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.btn{display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--blue);background:var(--blue);color:#fff;text-decoration:none;border-radius:8px;padding:10px 18px;font-size:13px;font-weight:600}.btn:hover{background:#2444ce;color:white}.btn.secondary{background:#fff;border-color:#d6dff0;color:var(--ink)}.btn[aria-pressed=true]{background:#eaf1ff;border-color:#a1b5ef;color:#2244ba}.small-link{font-size:13px}.learning-route{margin:28px 0 37px;display:flex;gap:22px;align-items:center;border-bottom:1px solid var(--line);padding-bottom:28px}.learning-route>strong{font-size:12px;white-space:nowrap}.route-items{display:flex;align-items:center;gap:15px;flex-wrap:wrap}.route-items a{font-size:12px;color:var(--muted);text-decoration:none}.route-items a:hover{color:var(--blue)}.route-items b{font:10px monospace;color:var(--blue);margin-right:6px}.route-items span{color:#c3ccdd;font-size:12px}.library-head{display:flex;justify-content:space-between;gap:25px;align-items:center;margin-bottom:23px}.library-head h2{font-size:25px;margin:0}.search{position:relative;min-width:310px;max-width:100%}.search input{width:100%;border:1px solid #dbe2ee;border-radius:8px;background:#fafbfe;padding:10px 14px;font-size:13px}.filter-bar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-bottom:23px}.filter{border:1px solid var(--line);background:white;color:var(--muted);padding:7px 15px;border-radius:30px;font-size:12px}.filter[aria-pressed=true]{border-color:var(--blue);background:var(--blue);color:white}.result{margin:0 0 0 auto;color:var(--muted);font-size:12px}.video-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:28px;margin-bottom:24px}.video-card{border:1px solid var(--line);border-radius:15px;overflow:hidden;background:white;min-width:0;transition:box-shadow .2s}.video-card:hover{box-shadow:0 10px 28px #1b2b560a}.card-cover{position:relative;display:block;aspect-ratio:16/8;overflow:hidden;background:#17233d}.card-cover img{display:block;width:100%;height:100%;object-fit:cover}.card-cover .play-dot{width:42px;height:42px;left:auto;right:18px;top:auto;bottom:18px;font-size:15px}.card-body{padding:22px 25px}.card-body h3 a{color:var(--ink);text-decoration:none}.card-body p{color:var(--muted);font-size:14px;margin:0 0 17px}.card-bottom{display:flex;align-items:center;justify-content:space-between;gap:12px;border-top:1px solid var(--line);padding-top:15px}.card-bottom a{font-size:13px;text-decoration:none;font-weight:600}.save{border:0;background:none;color:var(--muted);font-size:12px;padding:4px 0}.save[aria-pressed=true]{color:var(--blue)}.micro{font-size:12px;color:var(--muted)}.storage-status{min-height:22px;margin:8px 0;color:#9a5d28;font-size:12px}.empty{border:1px dashed #cbd5e8;border-radius:12px;padding:35px;text-align:center;background:var(--paper);margin-bottom:25px}.empty h3{margin-bottom:6px}.empty p{color:var(--muted);font-size:14px}.bottom-grid{display:grid;grid-template-columns:1fr 1fr;gap:35px;border-top:1px solid var(--line);padding:36px 0 45px;margin-top:34px}.bottom-grid h2{font-size:20px}.bottom-grid p{font-size:14px;color:var(--muted)}.footer{border-top:1px solid var(--line);padding:28px 0 34px;color:var(--muted);font-size:12px}.footer-inner{display:flex;justify-content:space-between;gap:25px}.footer p{margin:0 0 6px}.footer a{color:var(--muted);text-decoration:none}.footer nav{display:flex;gap:18px;flex-wrap:wrap}.crumb{display:flex;gap:9px;flex-wrap:wrap;font-size:12px;color:var(--muted);margin:24px 0 21px}.crumb a{text-decoration:none}.watch-heading{display:flex;justify-content:space-between;align-items:start;gap:25px}.watch-heading h1{font-size:clamp(28px,3.3vw,38px);margin-bottom:12px;max-width:850px}.watch-meta{display:flex;gap:15px;flex-wrap:wrap;font-size:12px;color:var(--muted);margin:0 0 22px}.watch-layout{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:26px;align-items:start}.player-panel{min-width:0}.player{aspect-ratio:16/9;background:#14203b;border-radius:12px;overflow:hidden}.player iframe{display:block;width:100%;height:100%;border:0}.player-tools{display:flex;justify-content:space-between;gap:15px;align-items:center;flex-wrap:wrap;margin-top:13px}.player-tabs{display:flex;gap:7px}.player-tabs button{border:1px solid var(--line);background:white;color:var(--muted);border-radius:6px;font-size:12px;padding:6px 10px}.player-tabs button[aria-pressed=true]{background:#eaf0ff;border-color:#bccbf4;color:var(--blue)}.player-status{font-size:11px;color:var(--muted);margin:10px 0}.player-direct{display:flex;gap:14px;font-size:12px;flex-wrap:wrap}.watch-sidebar{border:1px solid var(--line);border-radius:12px;padding:22px}.watch-sidebar h2{font-size:18px;margin-bottom:18px}.watch-sidebar ol{margin:0;padding:0;list-style:none}.watch-sidebar li{padding:14px 0;border-bottom:1px solid var(--line)}.watch-sidebar li:last-child{border-bottom:0;padding-bottom:0}.watch-sidebar a{text-decoration:none;color:var(--muted);font-size:13px;display:block}.watch-sidebar a[aria-current]{color:var(--blue);font-weight:650}.watch-sidebar span{font:10px monospace;color:#8e9bb3;display:block;margin-bottom:3px}.read-jump{display:flex;gap:22px;font-size:13px;padding:20px 0;margin:12px 0 28px;border-bottom:1px solid var(--line);flex-wrap:wrap}.read-jump a{text-decoration:none}.notes-layout{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:26px;padding-bottom:45px}.notes{min-width:0}.notes section{margin-bottom:37px}.notes h2{font-size:25px}.notes p,.notes li{font-size:15px}.note-list{padding:0;list-style:none;counter-reset:notes}.note-list li{counter-increment:notes;position:relative;padding:15px 18px 15px 48px;background:#f4f6fb;border-radius:9px;margin-bottom:10px}.note-list li:before{content:'0' counter(notes);position:absolute;left:16px;top:17px;color:var(--blue);font:11px monospace}.note-label{font-size:12px!important;color:var(--muted)}.practice{background:#fff8f2;border:1px solid #f1e1d4;border-radius:12px;padding:23px}.practice h3{font-size:17px}.practice p{font-size:14px;margin-bottom:14px}.practice p:last-child{margin:0}.copy-box{margin-top:20px;padding:21px;border:1px solid var(--line);border-radius:12px}.copy-box textarea{width:100%;height:200px;display:block;border:1px solid #d7dfee;border-radius:8px;padding:14px;font:12px/1.85 ui-monospace,'PingFang SC',monospace;resize:vertical;background:#fafbfe;color:var(--ink);margin:13px 0 16px}.copy-box label{font-size:13px;font-weight:600}.copy-status{min-height:23px;font-size:12px!important;color:#367353;margin:10px 0 0}.source-list{padding:0;list-style:none}.source-list li{padding:12px 0;border-bottom:1px solid var(--line);font-size:13px}.source-list small{display:block;color:var(--muted);font-size:12px}.related-box{border:1px solid var(--line);border-radius:12px;padding:22px;margin-top:8px}.related-box h3{font-size:17px}.related-box p{font-size:13px;color:var(--muted)}.about-copy{max-width:820px;padding-bottom:45px}.about-copy h1{font-size:37px}.about-copy h2{font-size:24px;margin-top:35px}.about-copy p,.about-copy li{font-size:15px}.skip{position:absolute;top:-90px;background:white;padding:10px;z-index:10}.skip:focus{top:8px}[hidden]{display:none!important}.js-only{display:none}.has-js .js-only{display:inline-flex}.has-js .filter-bar.js-only{display:flex}.has-js .search.js-only{display:block}.noscript-note{padding:15px;background:var(--paper);font-size:13px;color:var(--muted)}@media(max-width:900px){.watch-layout,.notes-layout{grid-template-columns:1fr}.watch-sidebar{padding:17px}.watch-sidebar ol{display:grid;grid-template-columns:repeat(2,1fr);gap:12px 20px}.watch-sidebar li{padding:6px 0;border:0}.feature-copy{padding:22px}.feature-copy h2{font-size:24px}.related-box{margin:0}.edition{display:none}}@media(max-width:650px){.shell{width:calc(100% - 36px)}.header{height:auto;min-height:85px;padding:18px 0;gap:14px;flex-wrap:wrap}.brand{font-size:20px}.brand img{width:30px;height:30px}.nav{font-size:12px;gap:15px}.intro{padding:30px 0 24px}.intro h1{font-size:34px}.featured{grid-template-columns:1fr}.feature-copy{padding:23px}.feature-copy h2{font-size:25px}.learning-route{align-items:start;gap:14px;flex-direction:column;margin-top:23px}.route-items{gap:8px 13px}.route-items span{display:none}.library-head{flex-direction:column;gap:17px;align-items:stretch}.search{min-width:0}.filter-bar{gap:8px}.filter{font-size:11px;padding:7px 12px}.result{width:100%;margin:7px 0 0}.video-grid{grid-template-columns:1fr;gap:20px}.card-body{padding:21px}.bottom-grid{grid-template-columns:1fr;gap:22px;padding-top:30px}.footer-inner{flex-direction:column;gap:18px}.watch-heading{display:block}.watch-heading>.save{margin-bottom:16px}.watch-meta{gap:8px 14px}.watch-layout{gap:18px}.player{border-radius:9px}.player-tools{gap:10px}.notes h2{font-size:23px}.read-jump{gap:18px}.practice,.copy-box{padding:19px}.crumb{font-size:11px}.about-copy h1{font-size:32px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.video-card{transition:none}}
