:root{color-scheme:dark;--bg:#171c1e;--stage:#22292c;--panel:#202628;--line:#ffffff14;--ink:#ecece5;--muted:#a5aeaf;--gold:#d3b480;--cyan:#76c5d0;--font:"Segoe UI","Microsoft YaHei",sans-serif;font-family:var(--font);color:var(--ink);background:var(--bg);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,select,input{font:inherit}button,select{color:inherit}button{cursor:pointer;border:1px solid transparent;background:transparent;border-radius:7px;padding:9px 13px;transition:background .15s,color .15s,border-color .15s;font-size:12px;white-space:nowrap}button:hover:not(:disabled){background:#ffffff0b;color:#fff}button:disabled,select:disabled{opacity:.35;cursor:default}button:focus-visible,select:focus-visible,input:focus-visible,summary:focus-visible{outline:2px solid var(--gold);outline-offset:3px}button[aria-pressed=true]{color:#f0d8a9;background:#d3b41512;border-color:#d3b48045}button:disabled[aria-pressed=true]{border-color:var(--line)}[hidden]{display:none!important}
#app{height:100svh;min-height:640px;display:flex;flex-direction:column;padding:0 28px 14px;gap:14px;max-width:2200px;margin:auto}.masthead{min-height:96px;display:flex;align-items:center;justify-content:space-between;gap:24px;flex-shrink:0;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:14px;flex-shrink:0}.brand-mark{height:42px;width:42px;display:grid;place-items:center;color:var(--gold);border:1px solid #d3b48055;font:25px "SimSun",serif;border-radius:4px}.eyebrow{font-size:9px;letter-spacing:.16em;color:var(--gold);margin:0 0 5px}.eyebrow span{border-left:1px solid #ffffff25;padding-left:10px;margin-left:8px;color:var(--muted)}h1{font:500 26px "SimSun",serif;letter-spacing:.08em;margin:0}h1 span{font:10px var(--font);letter-spacing:.08em;color:var(--muted);margin-left:12px}.lesson-tabs{display:flex;gap:4px;background:#111719;padding:5px;border:1px solid var(--line);border-radius:10px}.lesson-tabs button{padding:10px 17px;font-size:12px}.mode-dot{display:inline-block;width:5px;height:5px;border-radius:50%;margin:0 7px 2px 0}.drive{background:var(--gold)}.valve{background:var(--cyan)}.details-toggle{border-color:#ffffff22;font-size:12px;min-width:82px}.details-toggle span{font-size:16px;margin-left:10px;color:var(--gold)}
.workspace{display:flex;gap:14px;flex:1;min-height:0}.stage{position:relative;flex:1;min-width:0;overflow:hidden;border:1px solid var(--line);border-radius:14px;background:var(--stage)}#viewport{position:absolute;inset:0}canvas{display:block;width:100%;height:100%;touch-action:none}.stage-top{position:absolute;top:20px;left:22px;right:22px;display:flex;justify-content:space-between;pointer-events:none}.stage-kicker{font-size:10px;color:#a4afb0;letter-spacing:.1em;margin:0 0 8px}.stage-kicker span{color:#e1d7c2}#stage-hint{font-size:11px;color:#aeb9bb;margin:0}.live-tag{font-size:9px;letter-spacing:.05em;color:#b9c4c4}.live-tag i{display:inline-block;width:5px;height:5px;background:#adc8b5;border-radius:50%;margin-right:6px}.viewbar{position:absolute;bottom:14px;left:18px;right:18px;display:flex;align-items:center;gap:10px;padding:7px 9px;background:#192022e8;border:1px solid var(--line);border-radius:9px;backdrop-filter:blur(12px)}.view-label{font-size:10px;color:var(--muted);padding:0 8px;white-space:nowrap}.view-tools{display:flex;gap:2px;flex:1;flex-wrap:wrap}.view-tools button{font-size:11px;padding:8px 12px}.supplements{border-left:1px solid var(--line);border-radius:0;font-size:10px;color:#b7c0bf;padding:6px 10px}.supplements[aria-pressed=true]{border-color:transparent;border-left-color:var(--line);background:transparent;color:#b7c0bf}
.lesson{width:324px;flex-shrink:0;display:flex;flex-direction:column;background:var(--panel);border:1px solid var(--line);border-radius:14px;min-height:0}.panel-head{display:flex;justify-content:space-between;align-items:center;padding:12px 18px;border-bottom:1px solid var(--line);flex-shrink:0;font-size:11px;color:#c8ceca}.panel-head button{font-size:20px;padding:0 8px;color:var(--muted)}.panel-scroll{overflow:auto;padding:22px;scrollbar-width:thin;scrollbar-color:#807256 transparent}.section-index{font-size:10px;color:var(--gold);letter-spacing:.09em;margin:0 0 10px}.lesson h2{font:500 23px "SimSun",serif;line-height:1.5;margin:0 0 12px}.lesson p{font-size:12px;line-height:1.85;color:#adb8b8}.lesson .intro{margin:0 0 20px}.lesson h3{font-size:11px;font-weight:500;color:#e4e5dd;margin:22px 0 10px}.lesson h3 span{float:right;font-weight:400;font-size:9px;color:var(--muted)}.color-key{display:flex;gap:16px;font-size:10px;color:#c8ceca;padding:12px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.color-key i{display:inline-block;width:6px;height:6px;border-radius:50%;margin:0 6px 1px 0}#part-list{display:flex;flex-wrap:wrap;gap:6px}#part-list button{background:#ffffff04;border-color:var(--line);font-size:11px;padding:8px 9px}#part-list button[aria-pressed=true]{color:#f0d8a9;border-color:#d3b48070;background:#d3b4800c}.part-info{border-left:2px solid #c8a56b;padding:3px 0 3px 12px;margin-top:20px}.part-info strong{font-size:12px;color:#e9d4ae}.part-info p{margin:8px 0 0;font-size:11px}.diagram-head{display:flex;align-items:center;justify-content:space-between;margin-top:14px}.diagram-head h3{margin:0}.cutaway-toggle{font-size:10px;color:var(--muted);display:flex;gap:4px;align-items:center}.cutaway-toggle input{accent-color:var(--gold)}#cylinder-diagram{width:100%;margin-top:12px;background:#172022;border:1px solid var(--line);border-radius:7px;padding:6px}svg text{font-family:var(--font)}.lesson .diagram-note{font-size:10px;line-height:1.8;color:#9ba8a9;margin:8px 0 0}.evidence{border-top:1px solid var(--line);margin-top:25px;padding-top:16px}.evidence summary{font-size:10px;color:#b4bfbd;cursor:pointer}.evidence p{font-size:10px}.guide{list-style:none;padding:0;margin:25px 0 0}.guide li{display:flex;gap:14px;margin-bottom:22px;align-items:start}.guide li>span{font-size:11px;color:var(--gold);padding-top:2px;font-variant-numeric:tabular-nums}.guide strong{font-size:12px;font-weight:500}.guide p{font-size:11px;margin:6px 0}
.bottom{flex-shrink:0}.transport{display:flex;align-items:center;gap:24px;padding:0 2px 12px;border-bottom:1px solid var(--line)}.playback{display:flex;gap:6px;flex-shrink:0}.transport button{font-size:11px;border-color:var(--line);padding:10px 13px}.transport .primary{min-width:98px;color:#1b2224;background:var(--gold);border-color:var(--gold);font-weight:600}.transport .primary:hover:not(:disabled){background:#e1c595;color:#1b2224}.timeline{display:flex;align-items:center;gap:18px;flex:1;min-width:80px}.timeline input{width:100%;min-width:30px;accent-color:var(--gold);height:5px;cursor:pointer}.timeline output{font-size:10px;color:#b5c0bf;min-width:90px;font-variant-numeric:tabular-nums;white-space:nowrap}.controls{display:flex;align-items:center;gap:6px;flex-shrink:0}.speed-label{font-size:10px;color:var(--muted);white-space:nowrap;margin-right:10px}select{background:#232c2f;border:1px solid var(--line);border-radius:5px;padding:8px 3px;margin-left:5px;font-size:11px}.meta-row{display:flex;align-items:center;gap:20px;padding-top:11px;font-size:9px;line-height:1.5;color:#a0adad}.meta-row #status{color:#cdb68c;min-width:170px}.scope-note{margin-left:auto}.interaction-hint{color:#98a7a7}kbd{font:9px var(--font);border:1px solid #ffffff20;border-radius:3px;padding:1px 3px;margin:0 2px}.mobile-hint{display:none}
.loading{position:absolute;top:45%;left:50%;transform:translate(-50%,-50%);width:min(330px,86%);background:#1b2325f5;border:1px solid #ffffff22;padding:24px;border-radius:12px;box-shadow:0 16px 80px #0004}.loading strong{float:right;color:var(--gold);font-size:13px}.loading-label{font-size:13px}.loading progress{display:block;width:100%;height:4px;margin:18px 0;accent-color:var(--gold)}.loading p{font-size:11px;color:var(--muted);line-height:1.7}.loading button{border-color:var(--line)}
@media(max-width:1200px){#app{padding-left:20px;padding-right:20px}.masthead{gap:12px}.lesson-tabs button{padding:10px 12px}.view-label{display:none}.viewbar{gap:5px;left:12px;right:12px}.view-tools button{padding:8px}.transport{gap:14px}.lesson{width:300px}.scope-note{display:none}}
@media(max-width:900px){#app{height:auto;min-height:100svh;padding:0 12px 155px;gap:12px}.masthead{min-height:122px;flex-wrap:wrap;gap:12px;padding:16px 4px 12px}.brand{gap:10px}.brand-mark{width:36px;height:36px;font-size:22px}h1{font-size:23px}h1 span{font-size:9px;margin-left:8px}.eyebrow{font-size:8px}.details-toggle{margin-left:auto;min-width:72px;padding:8px 10px}.lesson-tabs{order:3;width:100%;justify-content:space-between;padding:4px;gap:2px}.lesson-tabs button{flex:1;padding:10px 6px;font-size:11px}.mode-dot{margin-right:5px}.workspace{flex-direction:column;gap:12px;flex:none}.stage{flex:none;height:calc(100svh - 292px);min-height:300px}.stage-top{top:16px;left:16px;right:16px}.stage-kicker{font-size:9px}#stage-hint{font-size:10px}.live-tag{font-size:8px}.viewbar{bottom:10px;left:10px;right:10px;flex-wrap:wrap;padding:6px;gap:5px}.view-tools{width:100%;flex:auto;display:grid;grid-template-columns:repeat(6,1fr);gap:2px}.view-tools button{padding:9px 2px;font-size:10px}.supplements{margin-left:auto;border:0;font-size:9px;padding:4px 6px}.supplements[aria-pressed=true]{border:0}.lesson{width:100%;max-height:none}.panel-head{padding:12px 18px}.panel-scroll{overflow:visible;padding:20px}.lesson h2{font-size:23px}.lesson .intro{font-size:12px}.lesson h3 span{font-size:10px}#part-list button{min-height:40px;padding:9px 12px}.bottom{position:fixed;left:0;right:0;bottom:0;background:#171c1ef5;backdrop-filter:blur(14px);padding:12px 16px max(12px,env(safe-area-inset-bottom));border-top:1px solid #ffffff18;z-index:4}.transport{display:grid;grid-template-columns:auto 1fr;padding-bottom:10px;gap:10px 12px}.playback{grid-column:1;grid-row:2}.timeline{grid-column:1/-1;grid-row:1;gap:12px}.controls{grid-column:2;grid-row:2;justify-content:flex-end;gap:4px}.transport button{font-size:10px;padding:9px 8px}.transport .primary{min-width:82px}.speed-label{font-size:0;margin-right:2px}.speed-label select{font-size:10px;margin-left:0;padding:8px 1px}.meta-row{padding-top:8px;font-size:8px;gap:8px;justify-content:space-between}.meta-row #status{min-width:0;max-width:65%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.interaction-hint{display:none}.mobile-hint{display:block;white-space:nowrap}.scope-note{display:none}}
@media(max-width:360px){h1 span{display:none}.brand-mark{display:none}.lesson-tabs button{font-size:10px}.mode-dot{display:none}.transport{column-gap:6px}.transport button{padding:9px 6px}.transport .primary{min-width:76px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;transition:none!important}}
#viewport{bottom:76px}
@media(max-width:900px){#viewport{bottom:92px}}
/* Keyboard access to the lamp easter egg; shown only while focused. */
.lantern-keyboard {position:absolute!important;width:1px;height:1px;padding:0;overflow:hidden;clip-path:inset(50%);white-space:nowrap;}
.lantern-keyboard:focus-visible {left:22px;top:76px;width:auto;height:auto;padding:10px 14px;clip-path:none;z-index:6;background:#252b2d;color:#ead8b4;border:1px solid #b69a64;border-radius:6px;}