:root{--bg:#0d0f12;--panel:#12151ae6;--line:#2a3038;--text:#e6e2da;--muted:#9aa0a8;--copper:#d98a4e;--copper-dim:#c07d45;--on:#ffcf6b;--blue:#6fb3ff;--font:"Inter", system-ui, -apple-system, "Segoe UI", sans-serif;--mono:"JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, monospace}*{box-sizing:border-box}html,body{background:var(--bg);height:100%;color:var(--text);font-family:var(--font);margin:0;overflow:hidden}#stage{position:fixed;inset:0}#stage canvas{display:block}#brand{pointer-events:none;position:fixed;top:14px;left:18px}#brand h1{letter-spacing:.02em;color:var(--copper);margin:0;font-size:18px}#brand p{color:var(--muted);margin:2px 0 0;font-size:12px}#timeline{background:#0d0f12b8;border-radius:10px;flex-direction:column;gap:2px;width:210px;padding:4px;display:flex;position:fixed;top:70px;bottom:70px;left:12px;overflow-y:auto}#timeline button{all:unset;cursor:pointer;color:var(--muted);border-left:2px solid #0000;border-radius:6px;grid-template-columns:44px 1fr;gap:6px;padding:6px 8px;font-size:12.5px;display:grid}#timeline button .yr{font-family:var(--mono);color:var(--copper-dim);padding-top:1px;font-size:11px}#timeline button:hover{color:var(--text);background:#ffffff0a}#timeline button.active{color:var(--text);border-left-color:var(--copper);background:#d98a4e1f}#timeline button.active .yr{color:var(--copper)}#timeline button:focus-visible{outline:2px solid var(--copper);outline-offset:-2px}#panel{background:var(--panel);border:1px solid var(--line);-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);border-radius:10px;flex-direction:column;width:400px;max-width:calc(100vw - 24px);display:flex;position:fixed;top:12px;bottom:70px;right:12px;overflow-y:auto}#panel-head{border-bottom:1px solid var(--line);padding:16px 18px 10px}#ch-year{font-family:var(--mono);color:var(--copper);font-size:12px}#ch-title{margin:4px 0;font-size:20px;line-height:1.2}#ch-tagline{color:var(--muted);margin:0;font-size:13px}#ch-controls{border-bottom:1px solid var(--line);flex-direction:column;gap:10px;padding:12px 18px;display:flex}#ch-controls:empty{display:none}#ch-body{flex:1 0 auto;padding:12px 18px 18px;font-size:13.5px;line-height:1.55}#ch-body h3{text-transform:uppercase;letter-spacing:.06em;color:var(--copper);margin:16px 0 6px;font-size:13px}#ch-body p{margin:0 0 10px}#ch-body ul{margin:0 0 10px;padding-left:18px}#ch-body li{margin-bottom:4px}#ch-body code,.mono{font-family:var(--mono);font-size:12px}#ch-body .key{border-left:3px solid var(--copper);background:#d98a4e14;border-radius:0 6px 6px 0;margin:10px 0;padding:6px 10px}#ch-body table{border-collapse:collapse;width:100%;margin:6px 0 12px;font-size:12px}#ch-body th,#ch-body td{border-bottom:1px solid var(--line);text-align:left;padding:4px 6px}#ch-body th{color:var(--muted);font-weight:500}#panel-nav{border-top:1px solid var(--line);background:#12151a;justify-content:space-between;padding:10px 14px;display:flex;position:sticky;bottom:0}button.btn,#panel-nav button{font:inherit;cursor:pointer;color:var(--text);background:#232830;border:1px solid #39414c;border-radius:6px;padding:6px 12px;font-size:13px}button.btn:hover,#panel-nav button:hover{border-color:var(--copper)}button.btn.primary{background:var(--copper);border-color:var(--copper);color:#1a1008;font-weight:600}button.btn.on{border-color:var(--on);color:var(--on);background:#ffcf6b33}button:disabled{opacity:.4;cursor:default}button:focus-visible,input:focus-visible,a:focus-visible,select:focus-visible{outline:2px solid var(--on);outline-offset:2px}#stage canvas:focus-visible{outline:2px solid var(--on);outline-offset:-2px}.row{flex-wrap:wrap;align-items:center;gap:6px;display:flex}.readout{font-family:var(--mono);border:1px solid var(--line);white-space:pre-wrap;background:#0a0c0f;border-radius:6px;padding:8px 10px;font-size:13px;line-height:1.5}.readout .hi{color:var(--on)}.readout .dim{color:var(--muted)}label.slider{color:var(--muted);flex-direction:column;gap:4px;font-size:12px;display:flex}label.slider input{width:100%;accent-color:var(--copper)}.hint{color:var(--muted);font-size:12px}canvas.plot{border:1px solid var(--line);background:#0a0c0f;border-radius:6px;width:100%;height:150px}table.truth{border-collapse:collapse;font-family:var(--mono);font-size:12px}table.truth td,table.truth th{border-bottom:1px solid var(--line);text-align:center;padding:2px 10px}table.truth tr.cur td{color:var(--on);background:#ffcf6b2e}#definition{background:var(--panel);border:1px solid var(--line);border-radius:10px;align-items:center;gap:14px;height:46px;padding:0 14px;display:flex;position:fixed;bottom:12px;left:12px;right:12px;overflow-x:auto}.def-title{color:var(--muted);white-space:nowrap;font-size:12px}#def-chips{gap:6px;display:flex}.chip{white-space:nowrap;color:#858c95;border:1px dashed #4a525d;border-radius:99px;padding:4px 10px;font-size:12px}.chip.got{border-style:solid;border-color:var(--copper);color:var(--text);background:#d98a4e24}.chip.new{animation:.8s pop}@keyframes pop{0%{transform:scale(1)}40%{background:#ffcf6b80;transform:scale(1.18)}to{transform:scale(1)}}#toast{background:var(--copper);color:#1a1008;pointer-events:none;border-radius:8px;padding:10px 18px;font-size:14px;font-weight:600;transition:transform .4s;position:fixed;top:18px;left:50%;transform:translate(-50%)translateY(-80px)}#toast.show{transform:translate(-50%)translateY(0)}.lbl{font-family:var(--font);color:var(--text);white-space:nowrap;pointer-events:none;background:#0a0c0fb8;border:1px solid #ffffff14;border-radius:4px;padding:2px 7px;font-size:12px}.lbl.small{padding:1px 5px;font-size:10.5px}.lbl.mono{font-family:var(--mono)}.lbl.big{font-size:15px;font-weight:600}.lbl.plain{background:0 0;border:none}.lbl.hi{color:var(--on);border-color:#ffcf6b80}.lbl.accent{color:var(--copper)}@media (width<=900px){#timeline{flex-direction:row;width:auto;height:40px;inset:auto 8px 64px;overflow-x:auto}#timeline button{white-space:nowrap;grid-template-columns:auto}#timeline button .ttl{display:none}#panel{width:auto;height:46vh;inset:auto 8px 110px}#definition{bottom:8px;left:8px;right:8px}#timeline,#definition{scrollbar-width:thin}#brand{display:none}.lbl{padding:1px 5px;font-size:10px}.lbl.small{padding:0 3px;font-size:8.5px}.lbl.big{font-size:12px}}.driver{border:1px solid var(--line);border-left:3px solid var(--fc);background:#ffffff05;border-radius:0 8px 8px 0;margin:2px 0 10px;padding:8px 12px}.driver-head{text-transform:uppercase;letter-spacing:.06em;color:var(--muted);align-items:center;gap:8px;font-size:11px;display:flex}.driver .force{color:#111;background:var(--fc);letter-spacing:.02em;text-transform:none;border-radius:99px;padding:1px 8px;font-size:11.5px;font-weight:600}.driver p{font-size:13px;margin:6px 0 0!important}.chain{grid-template-columns:1fr auto 1fr;align-items:stretch;gap:8px;margin:0 0 14px;font-size:12.5px;display:grid}.chain>div:not(.arrow){border:1px solid var(--line);background:#0f1216;border-radius:6px;padding:6px 8px}.chain span{text-transform:uppercase;letter-spacing:.06em;color:var(--copper);margin-bottom:2px;font-size:10.5px;display:block}.chain .arrow{color:var(--copper);align-self:center;font-size:18px}.force-dot{vertical-align:1px;border-radius:50%;width:7px;height:7px;margin-right:7px;display:inline-block}.legend{border-top:1px solid var(--line);color:var(--muted);flex-direction:column;gap:4px;margin:14px 8px 0;padding-top:10px;font-size:11.5px;display:flex}.legend-title{text-transform:uppercase;letter-spacing:.06em;color:var(--copper-dim);margin-bottom:2px;font-size:10.5px}@media (width<=900px){.legend{display:none}}.lesson{flex-direction:column;gap:6px;font-size:13px;line-height:1.5;display:flex}.lesson>div{border:1px solid var(--line);background:#0f1216;border-radius:6px;padding:7px 10px}.lesson span{text-transform:uppercase;letter-spacing:.06em;color:var(--copper);margin-bottom:2px;font-size:10.5px;display:block}.readout.code{white-space:pre;font-size:12px;overflow-x:auto}a.chref{color:var(--copper);border-bottom:1px dotted var(--copper);text-decoration:none}a.chref:hover{color:var(--on)}.code-edit{box-sizing:border-box;width:100%;color:var(--text);border:1px solid var(--line);font-family:var(--mono);resize:vertical;background:#0f1216;border-radius:6px;padding:6px 8px;font-size:12px;line-height:1.45}textarea.code-edit{white-space:pre;min-height:200px}.code-edit:focus{border-color:var(--copper);outline:none}.sr-only{clip:rect(0 0 0 0);white-space:nowrap;border:0;width:1px;height:1px;margin:-1px;padding:0;position:absolute;overflow:hidden}#kb-ring{pointer-events:none;border:2px solid var(--on);z-index:5;border-radius:8px;position:fixed;box-shadow:0 0 0 2px #0009}@media (prefers-reduced-motion:reduce){.chip.new{animation:none}#toast{transition:none}*{scroll-behavior:auto!important}}.checks{border-top:1px solid var(--line);margin-top:18px;padding-top:4px}.checks .q{margin:10px 0 14px}.checks .q>p{margin:0 0 6px}.checks .choices{flex-direction:column;gap:5px;display:flex}.checks .choice{font:inherit;text-align:left;cursor:pointer;color:var(--text);background:#1a1e24;border:1px solid #39414c;border-radius:6px;padding:6px 10px;font-size:13px}.checks .choice:hover:not(:disabled){border-color:var(--copper)}.checks .choice:disabled{opacity:1;cursor:default}.checks .choice.right{background:#6fcf7a24;border-color:#6fcf7a}.checks .choice.wrong{color:var(--muted);border-color:#e0584f;text-decoration:line-through}.checks .why{margin:6px 0 0;font-size:12.5px}.checks .why .btn{margin-left:4px;padding:2px 8px;font-size:12px}#timeline button.checked .ttl:after{content:" ✓";color:#6fcf7a}@media (width<=900px){#timeline button.checked .yr:after{content:" ✓";color:#6fcf7a}}