.wide-stage{width:min(1120px,calc(100vw - 300px));margin:42px 50%;translate:-50% 0}.video-shell{border:1px solid var(--line);background:var(--lab-surface);padding:14px;margin-top:28px}.video-shell video{display:block;width:100%;height:auto;aspect-ratio:16/9;background:#171915}.video-meta{display:flex;justify-content:space-between;gap:16px;margin-top:10px;font:11px/1.5 var(--sans);color:var(--quiet)}.motion-alternative{display:none;font:13px/1.6 var(--sans);padding:12px 0}.prediction-panel{margin:34px 0;border:1px solid var(--line);padding:24px;background:var(--lab-surface)}.prediction-panel fieldset{border:0;padding:0;margin:0}.prediction-panel legend{font:700 14px/1.5 var(--sans);margin-bottom:13px}.prediction-actions{display:flex;flex-wrap:wrap;gap:10px}.prediction-result{min-height:28px;margin:14px 0 0;font:14px/1.6 var(--sans)}.filmstrip{margin-top:36px}.step-controls{position:sticky;top:87px;z-index:10;border:1px solid var(--line);background:var(--paper);padding:12px;margin-bottom:18px;box-shadow:0 8px 24px var(--shadow-color,#0001)}.step-controls[hidden]{display:none}.beat-buttons{display:grid;grid-template-columns:repeat(6,1fr);gap:6px}.beat-buttons button{padding:8px 5px;min-height:50px;font:11px/1.25 var(--sans)}.beat-buttons button[aria-pressed=true]{background:var(--ink);color:var(--paper);font-weight:700}.transport{display:flex;align-items:center;justify-content:space-between;gap:8px;margin-top:9px}.transport-group{display:flex;gap:8px}.transport button{font:12px/1.2 var(--sans)}.step-status{font:12px/1.45 var(--sans);color:var(--quiet);text-align:center}.film-frame{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(260px,.95fr);gap:28px;border-top:1px solid var(--line);padding:30px 0 46px}.film-frame[hidden]{display:none}.film-frame header{grid-column:1/-1;display:flex;align-items:start;justify-content:space-between;gap:16px}.frame-kicker{font-size:10px;color:var(--quiet);margin-bottom:7px}.film-frame h3{margin:0;font-size:29px}.frame-media{min-width:0}.frame-media img{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;border:1px solid var(--line);background:var(--wash)}.frame-media .frame-alt{font:11px/1.55 var(--sans);color:var(--quiet);margin-top:8px}.frame-copy{font-size:17px;line-height:1.65}.frame-copy p{margin-bottom:15px}.frame-equation{font:20px/1.45 var(--serif);padding:14px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);margin:17px 0;font-variant-numeric:tabular-nums;overflow-wrap:anywhere}.frame-values{display:grid;grid-template-columns:1fr auto;gap:5px 16px;font:13px/1.5 ui-monospace,Consolas,monospace;margin:15px 0}.frame-takeaway{font:700 13px/1.55 var(--sans);padding-top:14px;border-top:2px solid var(--student)}.branch-mini{position:relative;height:170px;border:1px solid var(--line);background:var(--lab-surface);overflow:hidden;margin:10px 0 18px}.branch-mini .prompt,.branch-mini .token{position:absolute;display:flex;align-items:center;justify-content:center;border-radius:6px;font:700 16px var(--sans)}.branch-mini .prompt{left:7%;top:62px;width:62px;height:42px;border:2px solid var(--ink);background:var(--paper)}.branch-mini .token.a{left:48%;top:23px;width:70px;height:38px;border:1px dashed var(--quiet);color:var(--quiet)}.branch-mini .token.b{left:48%;top:108px;width:70px;height:38px;background:var(--student);color:#fff;border:2px solid var(--student)}.branch-mini .line{position:absolute;left:18%;width:32%;border-top:2px solid var(--student);transform-origin:left}.branch-mini .line.a{top:76px;rotate:-13deg;border-top-style:dashed;border-top-color:var(--quiet)}.branch-mini .line.b{top:92px;rotate:13deg}.branch-mini .label-a,.branch-mini .label-b{position:absolute;left:70%;font:12px/1.3 var(--sans)}.branch-mini .label-a{top:31px;color:var(--quiet);text-decoration:line-through}.branch-mini .label-b{top:117px;color:var(--student);font-weight:700}.branch-mini .query{position:absolute;left:61%;top:99px;width:34%;border-top:2px dashed var(--teacher)}.branch-mini .query-label{position:absolute;right:4%;top:68px;color:var(--teacher);font:700 11px/1.3 var(--sans)}.no-video-copy{font:13px/1.6 var(--sans);color:var(--quiet)}
@media(max-width:1120px){.wide-stage{width:100%;margin-left:0;margin-right:0;translate:none}.step-controls{top:76px}}
@media(max-width:760px){.video-shell{padding:8px;margin-left:-8px;margin-right:-8px}.video-meta{display:block}.film-frame{grid-template-columns:1fr;gap:18px}.beat-buttons{grid-template-columns:repeat(3,1fr)}.step-controls{top:70px;padding:8px;margin-left:-8px;margin-right:-8px}.transport{align-items:stretch;flex-direction:column}.transport-group{display:grid;grid-template-columns:repeat(3,1fr)}.step-status{text-align:left}.frame-copy{font-size:16px}.film-frame header{display:block}.film-frame header .truth-chip{margin-top:10px}.branch-mini{height:190px}.branch-mini .label-a,.branch-mini .label-b{left:65%}.branch-mini .query-label{right:2%;max-width:90px}}
@media(max-width:380px){.beat-buttons{grid-template-columns:repeat(2,1fr)}.branch-mini .query-label{display:none}.frame-equation{font-size:17px}.frame-values{grid-template-columns:1fr;font-size:12px}.frame-values strong{margin-bottom:7px}}
@media print{.wide-stage{width:100%;margin:20px 0;translate:none}.filmstrip .film-frame[hidden]{display:grid!important}.film-frame{grid-template-columns:1fr 1fr;padding:16px 0 22px;gap:16px}.frame-media img{max-height:290px;object-fit:contain}.branch-mini{height:140px}.film-frame h3{font-size:15pt}.frame-copy{font-size:9pt}.frame-equation{font-size:10pt}.frame-alt{font-size:7.5pt!important}}