:root{--bg:#06070a;--panel:#0c1015;--line:#253139;--muted:#99a8b0;--ink:#eff4ee;--mint:#6df2c2;--blue:#5bbcff;--amber:#f7c948;font-family:Inter,"Segoe UI","Microsoft JhengHei",sans-serif;font-synthesis:none;line-height:1.6;scroll-behavior:smooth}
body{min-width:360px}button,input,select{font:inherit}button,a,input,select,summary{-webkit-tap-highlight-color:transparent}button,select{border:1px solid var(--line);border-radius:5px;background:#11181e;color:var(--ink);min-height:44px;padding:8px 12px}button,summary{cursor:pointer}button{transition:background .15s,border-color .15s,transform .15s}button:hover,select:hover{border-color:#627b80;background:#1b272e}button:active{transform:translateY(1px)}button:disabled{opacity:.45;cursor:wait}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible,canvas:focus-visible{outline:2px solid var(--mint);outline-offset:4px}a{color:inherit;text-decoration:none}a:hover{color:var(--mint)}h1,h2,h3,p{margin:0}h1{font-size:clamp(30px,3.2vw,48px);line-height:1.25;letter-spacing:-.055em;font-weight:650}h2{font-size:24px;line-height:1.4;letter-spacing:-.025em}h3{font-size:17px;font-weight:600}input[type=range]{display:block;width:100%;height:32px;accent-color:var(--mint);cursor:pointer;margin:6px 0 0}input[type=checkbox]{accent-color:var(--mint);width:17px;height:17px;flex:none}select{width:100%}output{font-variant-numeric:tabular-nums;font-family:ui-monospace,Consolas,monospace}code{font-family:ui-monospace,Consolas,monospace;overflow-wrap:anywhere;color:var(--mint);font-size:.93em}canvas{display:block;width:100%;touch-action:pan-y}.topbar{height:76px;display:flex;align-items:center;gap:20px;border-bottom:1px solid var(--line);margin:0 4vw}.brand{display:flex;align-items:center;gap:12px;font-size:14px;letter-spacing:.04em}.brand b{font-weight:500;color:var(--muted)}.brand-mark{width:34px;height:34px;border:1px solid var(--mint);display:grid;place-items:center;color:var(--mint);font:600 20px ui-monospace,monospace}.edition{margin-left:auto;color:var(--muted);font:11px ui-monospace,monospace;letter-spacing:.12em}.back-link{min-height:44px;padding:10px 0 10px 25px;font-size:13px;border-left:1px solid var(--line)}main{max-width:1600px;margin:auto;padding:0 4vw}.intro{display:flex;align-items:flex-end;justify-content:space-between;gap:28px;padding:46px 0 34px}.eyebrow{font:11px/1.6 ui-monospace,Consolas,monospace;letter-spacing:.16em;color:var(--mint);display:block}.intro .eyebrow{margin-bottom:12px}.status-dot{display:inline-block;width:6px;height:6px;border-radius:50%;background:var(--mint);margin-right:8px}.intro-copy{color:var(--muted);font-size:15px;margin-top:16px;line-height:1.85}.mobile-break{display:none}.lesson-link{border-bottom:1px solid var(--line);padding:15px 0;max-width:300px}.lesson-link span{display:block;font-size:12px;color:var(--muted)}.lesson-link strong{display:block;font-size:14px;font-weight:500;margin-top:6px}.laboratory{display:grid;grid-template-columns:minmax(0,1fr) 306px;border:1px solid var(--line);background:var(--panel)}.stage-column{min-width:0;padding:22px 24px 0}.stage-heading{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:15px}.stage-heading h2{font-size:20px;margin-top:3px}.stage-heading .eyebrow{font-size:10px;color:var(--muted)}.mode-badge{font-size:11px;color:var(--mint);border:1px solid #2c5c50;padding:5px 8px;white-space:nowrap}.canvas-shell{position:relative;height:470px;background:#080c10;border:1px solid #202c33;overflow:hidden}.canvas-shell canvas{height:100%}.canvas-key{position:absolute;left:18px;top:14px;display:flex;gap:18px;font-size:11px;color:var(--muted);pointer-events:none}.canvas-key span:before{content:"";width:13px;height:2px;display:inline-block;vertical-align:middle;margin-right:6px;background:#7e9299}.canvas-key .key-result:before{background:var(--mint)}.canvas-key .key-tip:before{background:var(--amber);width:5px;height:5px;border-radius:50%}.corner-note{position:absolute;left:16px;bottom:14px;right:62px;font-size:12px;color:#9fafb8;pointer-events:none}.expand-button{position:absolute;right:10px;bottom:9px;font-size:23px;line-height:1;padding:5px;width:44px;background:#0c141bc9}.transport{display:flex;align-items:center;gap:8px;padding:16px 0}.primary{background:var(--mint);color:#09241a;border-color:var(--mint);font-weight:650}.primary:hover{background:#a6ffdb;border-color:#a6ffdb}.play-button{min-width:94px}.progress-label{flex:1;display:flex;align-items:center;gap:10px;min-width:50px;margin:0 5px}.progress-label input{margin:0}.progress-label output{font-size:11px;color:var(--muted);min-width:35px}.speed-label select{font-size:12px}.readouts{display:grid;grid-template-columns:1fr 1.2fr 1fr;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:14px 0;gap:14px}.readouts>div+div{padding-left:18px;border-left:1px solid var(--line)}.readouts span{display:block;color:var(--muted);font-size:11px}.readouts strong{display:block;font:500 24px/1.6 ui-monospace,Consolas,monospace;letter-spacing:-.03em}.readouts abbr{text-decoration:none;cursor:help}.spectrum-panel{padding-top:14px}.spectrum-heading{display:flex;justify-content:space-between;gap:12px;font-size:12px;color:#ccd9dc}.spectrum-panel canvas{height:78px}.small{font-size:12px;line-height:1.7}.muted{color:var(--muted)}.status{font-size:12px;color:var(--muted);border-top:1px solid var(--line);padding:13px 0;min-height:47px}.status.error{color:#ff8da1}.controls{border-left:1px solid var(--line);padding:0 20px 18px;background:#10151b}.control-section{padding:20px 0;border-bottom:1px solid var(--line)}.control-section h3{font-size:15px;margin-bottom:14px}.control-section h3>span{font:12px ui-monospace,monospace;color:var(--mint);margin-right:10px}.presets{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:6px}.preset{height:65px;padding:5px;display:flex;align-items:center;flex-direction:column;justify-content:center;gap:2px;background:#121a20;font-size:11px;color:#b3c3c9}.preset .symbol{font-size:23px;font-family:serif;line-height:1.2}.preset[aria-pressed=true]{border-color:var(--mint);color:var(--mint);background:#162b27}.source-actions{display:flex;gap:6px;margin:10px 0}.source-actions button{flex:1;font-size:12px}.field{display:block;font-size:13px;margin:14px 0 8px}.field output{float:right;color:var(--mint)}.field select{margin-top:7px}.basis-note{margin-top:12px;color:var(--muted);font-size:12px;line-height:1.8}.terms-field output{font-size:28px;line-height:1}.terms-field input{margin-top:13px}.range-caption{display:flex;justify-content:space-between;font-size:10px;color:var(--muted)}.quick-terms{display:flex;gap:6px;margin:12px 0}.quick-terms button{flex:1;font:12px ui-monospace,monospace}.view-options{display:grid;gap:0}.check{display:flex;align-items:center;gap:8px;min-height:38px;font-size:12px;color:#c4d1d6;cursor:pointer}.reset-button{margin-top:15px;width:100%;background:transparent;color:var(--muted);font-size:12px}.photo-panel{padding-top:10px}.photo-panel canvas{height:165px;background:#080c10;border:1px solid var(--line)}.photo-panel button{width:100%;font-size:12px;margin:8px 0}.photo-panel select{font-size:12px}.understand{padding:75px 0 0;scroll-margin-top:24px}.section-title h2{font-size:32px;margin-top:8px}.section-title>p:last-child{color:var(--muted);margin-top:10px;font-size:15px}.explanation-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:34px;margin:35px 0}.explanation-grid article{border-top:1px solid var(--line);padding-top:20px}.lesson-number{font:11px ui-monospace,monospace;color:var(--mint)}.explanation-grid h3{margin:13px 0 10px}.explanation-grid p{font-size:14px;line-height:1.9;color:var(--muted)}.winding-lab{display:grid;grid-template-columns:1fr 1fr;border:1px solid var(--line);background:var(--panel);margin-top:30px}.winding-copy{padding:30px}.winding-copy h3{font-size:21px;margin:8px 0 20px}.winding-copy p:not(.eyebrow){font-size:14px;color:var(--muted);line-height:1.9;margin-top:12px}.winding-lab canvas{height:340px;border-left:1px solid var(--line)}.winding-value{display:block;font-size:13px;margin-top:18px;color:var(--mint)}.mint{color:var(--mint)}.technical{margin-top:28px;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}summary{padding:18px 0;min-height:48px;font-size:14px}.technical-body{max-width:850px;padding:0 0 28px}.technical-body p{font-size:14px;color:var(--muted);line-height:1.9;margin:12px 0 24px}.table-wrap{overflow:auto}table{width:100%;border-collapse:collapse;font-size:13px;text-align:left;font-variant-numeric:tabular-nums}caption{text-align:left;color:var(--muted);padding:10px 0}th,td{border-bottom:1px solid var(--line);padding:8px}th{color:var(--mint);font-weight:500}footer{display:flex;gap:30px;justify-content:space-between;padding:30px 0 40px;color:var(--muted);font-size:11px}footer>span{white-space:nowrap}footer p{text-align:right}footer a{text-decoration:underline;text-underline-offset:3px}dialog{background:#10171e;border:1px solid #3c535b;border-radius:8px;color:var(--ink);width:min(680px,calc(100vw - 24px));max-height:calc(100dvh - 24px);padding:24px;overflow:auto}dialog::backdrop{background:#000b;backdrop-filter:blur(4px)}.dialog-heading{display:flex;align-items:center;justify-content:space-between;gap:12px}.dialog-heading h2{margin-top:5px;font-size:23px}.dialog-heading button{font-size:18px}.dialog-heading+p{font-size:13px;color:var(--muted);margin:14px 0}#editor{height:300px;background:#070c11;border:1px solid var(--line);touch-action:none}.editor-options{display:flex;align-items:center;gap:8px;flex-wrap:wrap;padding:12px 0;font-size:12px}.editor-options>label:first-child{display:flex;align-items:center;gap:5px}.editor-options select{width:auto;font-size:12px}.editor-options button{font-size:12px}.coordinate-input{border-top:1px solid var(--line)}.coordinate-input label{display:inline-flex;gap:4px;margin-right:8px;align-items:center}.coordinate-input input{width:70px;background:#111b22;border:1px solid var(--line);color:var(--ink);min-height:44px;padding:7px}.coordinate-input button{font-size:12px}#draw-message{font-size:12px;color:var(--muted);margin:8px 0 14px}#use-drawing{width:100%}.sr-only{position:absolute!important;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.page-fullscreen{position:fixed!important;inset:0!important;z-index:20;background:var(--bg);height:100dvh!important}#canvas-shell:fullscreen{height:100vh;background:var(--bg)}
.topbar{height:64px}.intro{padding:28px 0 25px}.intro-copy{margin-top:12px}.canvas-shell{height:400px}.control-section{padding:16px 0}.control-section h3{margin-bottom:10px}.preset{height:53px}.control-section .small{font-size:11px}.basis-note{margin-top:8px}
@media(min-width:1600px){.canvas-shell{height:470px}}
@media(max-width:1120px){.laboratory{grid-template-columns:minmax(0,1fr) 280px}.stage-column{padding:18px 16px 0}.controls{padding:0 15px 16px}.canvas-shell{height:430px}.readouts strong{font-size:21px}.readouts>div+div{padding-left:10px}.speed-label{max-width:90px}.transport>button span{display:none}.lesson-link{max-width:220px}.explanation-grid{gap:20px}}
@media(max-width:850px){.laboratory{grid-template-columns:1fr}.controls{border-left:0;border-top:1px solid var(--line);display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 24px;padding:0 20px 18px}.controls .control-section:first-child{grid-row:span 2}.reset-button{grid-column:1/-1}.canvas-shell{height:420px}.stage-column{padding:20px 20px 0}.lesson-link{display:none}.intro{padding:32px 0 28px}.explanation-grid{gap:20px}.explanation-grid h3{font-size:16px}.winding-copy{padding:22px}.winding-copy h3{font-size:19px}}
@media(max-width:600px){.topbar{height:64px}.edition{display:none}.back-link{margin-left:auto;padding-left:14px}.brand{gap:8px;font-size:12px}.brand-mark{width:30px;height:30px}.intro{padding:28px 0 24px}h1{font-size:34px}.mobile-break{display:block}.intro-copy{font-size:14px;line-height:1.8}.intro .eyebrow{font-size:10px}.laboratory{margin:0 -1px}.stage-column{padding:16px 12px 0}.stage-heading h2{font-size:18px}.mode-badge{font-size:10px;padding:4px 6px}.canvas-shell{height:355px}.canvas-key{font-size:10px;left:11px;top:11px;gap:12px}.corner-note{font-size:10px;left:10px;bottom:12px}.transport{gap:5px;flex-wrap:wrap;padding:12px 0}.transport button{font-size:12px;padding:8px}.play-button{min-width:75px}.speed-label{max-width:86px}.speed-label select{padding:6px;font-size:11px}.progress-label{margin:0 3px;gap:4px}.progress-label output{display:none}.readouts{gap:6px;padding:12px 0}.readouts span{font-size:10px}.readouts strong{font-size:20px}.readouts>div+div{padding-left:8px}.spectrum-heading{font-size:11px}.spectrum-heading .small{font-size:10px}.spectrum-panel canvas{height:68px}.status{font-size:11px}.controls{display:block;padding:0 16px 16px}.control-section{padding:18px 0}.control-section h3{font-size:16px}.presets{grid-template-columns:repeat(3,minmax(0,1fr))}.preset{font-size:12px;height:66px}.control-section .small,.basis-note,.check,.source-actions button{font-size:13px}.check{min-height:44px}.view-options{grid-template-columns:1fr 1fr}.view-options label:last-child{grid-column:1/-1}.field{font-size:14px}.understand{padding-top:48px}.section-title h2{font-size:27px}.section-title>p:last-child{font-size:14px}.explanation-grid{grid-template-columns:1fr;gap:24px;margin-top:26px}.explanation-grid h3{font-size:18px}.winding-lab{grid-template-columns:1fr}.winding-copy{padding:20px}.winding-lab canvas{height:290px;border-left:0;border-top:1px solid var(--line)}footer{display:block;padding:24px 0}footer p{text-align:left;margin-top:12px;line-height:1.9}dialog{padding:16px}.dialog-heading h2{font-size:20px}#editor{height:250px}}
body{min-width:0}.brand{min-height:44px}input[type=range]{height:44px}.check{min-height:44px}.stage-column{align-self:start;position:sticky;top:12px;background:var(--panel)}
@media(max-width:850px) and (min-height:651px){.stage-column{top:0;z-index:2;border-bottom:1px solid var(--line)}.canvas-shell{height:250px}.stage-heading .eyebrow,.spectrum-panel{display:none}.stage-heading{margin-bottom:8px}.status{padding:8px 0;min-height:34px}}
@media(max-width:600px) and (min-height:651px){.stage-column{padding:10px 12px 0}.stage-heading h2{font-size:16px}.canvas-shell{height:200px}.transport{padding:8px 0}.readouts{padding:6px 0}.readouts strong{font-size:18px}.status{font-size:10px;line-height:1.5;min-height:32px}.controls :is(button,input,select){scroll-margin-top:410px;scroll-margin-bottom:12px}}
@media(max-height:650px){.stage-column{position:relative;top:0}}
@media(prefers-reduced-motion:reduce){:root{scroll-behavior:auto}button{transition:none}}