:root{--bg: #eef1f7;--panel: #ffffff;--panel-2: #f5f7fc;--edge: #e1e5ef;--edge-2: #d3d9e6;--ink: #1b2233;--muted: #5c6478;--faint: #98a1b5;--task: #d98200;--micro: #7c4dff;--timer: #0d9488;--network: #2563eb;--stack: #16a34a;--accent: #4f56e8;font-synthesis:none}*{box-sizing:border-box}html,body{margin:0;height:100%;background:var(--bg);color:var(--ink);font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,sans-serif;font-size:17px;-webkit-font-smoothing:antialiased}#app{height:100vh}.layout{display:grid;grid-template-columns:minmax(460px,32%) 1fr 268px;height:100vh;overflow:hidden}.editor-col{display:flex;flex-direction:column;gap:14px;padding:20px;border-right:1px solid var(--edge);background:linear-gradient(180deg,#f9fbff,#f2f5fb);min-height:0}.brand{font-size:22px;font-weight:700;letter-spacing:-.02em}.brand span{color:var(--accent)}.lesson-picker{display:flex;align-items:center;gap:10px}.lesson-picker label{font-size:13px;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.05em}#lesson{-webkit-appearance:none;-moz-appearance:none;appearance:none;background:var(--panel) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4l4 4 4-4' stroke='%235c6478' stroke-width='1.6' fill='none' stroke-linecap='round'/%3E%3C/svg%3E") no-repeat right 14px center;border:1px solid var(--edge-2);border-radius:10px;padding:11px 40px 11px 14px;font-size:15px;font-weight:600;color:var(--ink);cursor:pointer;flex:1}#lesson:focus{outline:none;border-color:var(--accent)}.run{background:var(--accent);color:#fff;border:none;font-weight:700;padding:11px 22px;border-radius:10px;cursor:pointer;font-size:15px}.run:hover{filter:brightness(1.06)}.blurb{margin:0;color:var(--muted);font-size:15px;line-height:1.55}.editor-wrap{flex:1;min-height:0;display:flex}#editor{flex:1;min-height:0;border:1px solid var(--edge-2);border-radius:12px;overflow:hidden;background:#fff}#editor .cm-editor{border-radius:12px;height:100%}.stage{display:grid;grid-template-rows:auto 1fr auto;gap:14px;padding:20px;min-height:0;overflow:hidden}.legend{display:flex;gap:20px;color:var(--muted);font-size:14px}.legend span{display:inline-flex;align-items:center;gap:7px}.sw{width:12px;height:12px;border-radius:4px;display:inline-block}.sw.task{background:var(--task)}.sw.micro{background:var(--micro)}.sw.timer{background:var(--timer)}.sw.network{background:var(--network)}.panes{display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:1fr auto;grid-template-areas:"callStack taskQueue microQueue" "background background background";gap:14px;min-height:0}.panel{background:var(--panel);border:1px solid var(--edge);border-radius:16px;display:flex;flex-direction:column;min-height:0;box-shadow:0 1px 3px #141e3c0a;transition:opacity .35s}.panel[data-pane=callStack]{grid-area:callStack}.panel[data-pane=taskQueue]{grid-area:taskQueue}.panel[data-pane=microQueue]{grid-area:microQueue}.panel[data-pane=background]{grid-area:background}.panel.dimmed{opacity:.35;filter:saturate(.5)}.panel header{padding:13px 16px;font-size:14px;font-weight:700;letter-spacing:.03em;text-transform:uppercase;color:var(--muted);border-bottom:1px solid var(--edge);display:flex;align-items:baseline;gap:9px;flex-wrap:wrap}.panel header small{text-transform:none;letter-spacing:0;font-weight:500;font-size:12.5px;color:var(--faint)}.body{padding:14px;overflow:auto;flex:1;display:flex;flex-direction:column;gap:10px;justify-content:flex-end}.body.col{justify-content:flex-end}.body.row{flex-direction:row;flex-wrap:wrap;align-content:flex-start;justify-content:flex-start;flex:none;min-height:56px}#p-taskQueue,#p-microQueue{justify-content:flex-start}.empty{color:#aab1c2;font-size:14px;font-style:italic;padding:4px 2px;align-self:flex-start}.item{border-radius:11px;padding:13px 16px;font-size:16px;font-family:ui-monospace,Menlo,monospace;border:1px solid var(--edge);background:var(--panel-2);color:var(--ink);animation:pop .28s ease}@keyframes pop{0%{opacity:0;transform:translateY(7px) scale(.97)}to{opacity:1;transform:none}}.item.frame{border-left:4px solid var(--stack)}.item.frame.top{box-shadow:0 0 0 1px var(--stack) inset;background:#ecfaf1}.item.queued{border-left:4px solid var(--task)}#p-microQueue .item.queued{border-left-color:var(--micro)}.item.queued.front{box-shadow:0 0 0 1px currentColor inset}#p-taskQueue .item.queued.front{color:var(--task);background:#fdf5e8}#p-microQueue .item.queued.front{color:var(--micro);background:#f3efff}.item.queued .label{color:var(--ink)}.item.bg{display:inline-flex;align-items:center;gap:11px}.item.bg .dot{width:11px;height:11px;border-radius:50%;flex:none}.item.bg.timer{border-left:4px solid var(--timer)}.item.bg.timer .dot{background:var(--timer);animation:pulse 1.1s infinite}.item.bg.network{border-left:4px solid var(--network)}.item.bg.network .dot{background:var(--network);animation:pulse 1.1s infinite}@keyframes pulse{0%,to{opacity:1}50%{opacity:.3}}.narration{display:flex;align-items:center;justify-content:space-between;gap:18px;background:var(--panel);border:1px solid var(--edge);border-radius:14px;padding:16px 20px}#note{margin:0;font-size:18px;line-height:1.5;color:var(--ink);flex:1}.controls{display:flex;align-items:center;gap:8px}.controls button{background:var(--panel);color:var(--ink);border:1px solid var(--edge-2);border-radius:10px;padding:10px 15px;cursor:pointer;font-size:17px;min-width:46px}.controls button:hover:not(:disabled){border-color:var(--accent)}.controls button:disabled{opacity:.4;cursor:not-allowed}.counter{color:var(--muted);font-size:15px;font-variant-numeric:tabular-nums;padding:0 10px;min-width:64px;text-align:center}.play{font-weight:600}.play.on{background:var(--accent);color:#fff;border-color:var(--accent)}.phases{border-left:1px solid var(--edge);background:linear-gradient(180deg,#f9fbff,#eef1f7);padding:24px 20px;overflow-y:auto;display:flex;flex-direction:column}.phases h2{margin:0 0 22px;font-size:20px;font-weight:700;letter-spacing:-.01em}.credit{margin:auto 0 0;padding-top:18px;font-size:13px;color:var(--faint)}.credit a{color:var(--accent);text-decoration:none}.credit a:hover{text-decoration:underline}.phase-list{list-style:none;margin:0;padding:0}.phase-list li{position:relative;display:flex;gap:14px;padding:0 0 26px}.phase-list li:not(:last-child):before{content:"";position:absolute;left:15px;top:32px;bottom:2px;width:2px;background:var(--edge-2)}.phase-list .num{flex:none;width:32px;height:32px;border-radius:50%;display:grid;place-items:center;font-size:15px;font-weight:700;background:#c9cfdd;color:#fff;z-index:1;transition:background .2s,transform .2s}.phase-list strong{display:block;font-size:16px;font-weight:600;color:#5b6274;line-height:1.9}.phase-list p{margin:5px 0 0;font-size:14px;line-height:1.5;color:var(--faint);display:none}.phase-list li.active .num{background:var(--accent);transform:scale(1.08);box-shadow:0 0 0 5px #4f56e826}.phase-list li.active strong{color:var(--ink);font-weight:700}.phase-list li.active p{display:block;color:var(--muted)}