.torus-stage{--fg:#1c2733;--muted:#4c6072;--c:#522097;--bg:radial-gradient(ellipse 80% 70% at 50% 30%, #f7f3fc 0%, #dad2e5 78%);--pane:#fff6;--chip:#ffffffb8;--chip-edge:#1c273329;--pop:#ffffffe0;z-index:50;visibility:hidden;color-scheme:light;color:var(--fg);background:var(--bg);font-size:1rem;line-height:1.5;position:fixed;inset:0}:root[data-scheme=dark] .torus-stage{--fg:#eef1f6;--muted:#a7b3c2;--c:#b384f5;--bg:radial-gradient(ellipse 80% 70% at 50% 30%, #171c33 0%, #06070b 78%);--pane:#0e121c38;--chip:#0e121cb3;--chip-edge:#ffffff2e;--pop:#0c0f1acc;color-scheme:dark}.torus-stage.open{visibility:visible}.torus-stage .fig{width:100%;display:block;position:relative}.torus-stage .fig canvas{width:100%;height:100%;display:block;position:absolute;inset:0}.torus-stage .fig canvas.marks{touch-action:pan-y;cursor:grab}.torus-stage .fig:after{content:"";pointer-events:none;border-radius:1.25rem;transition:box-shadow .25s;position:absolute;inset:0;box-shadow:inset 0 0 0 1.5px #0000}.torus-stage .fig.grabbed:after{box-shadow:inset 0 0 0 1.5px color-mix(in srgb, var(--c) 70%, transparent), inset 0 0 2.5rem color-mix(in srgb, var(--c) 18%, transparent)}.torus-stage .fig.grabbed canvas.marks{touch-action:none}.torus-stage .fig .done{cursor:pointer;border:1px solid color-mix(in srgb, var(--c) 60%, transparent);background:var(--chip);backdrop-filter:blur(6px);color:var(--fg);font:inherit;opacity:0;pointer-events:none;border-radius:999px;padding:.4rem 1rem;font-size:.92rem;transition:opacity .25s;position:absolute;top:.75rem;right:.75rem}.torus-stage .fig.grabbed .done{opacity:1;pointer-events:auto}.torus-stage .touch-only{display:none}@media (hover:none){.torus-stage .touch-only{display:inline}.torus-stage .mouse-only{display:none}}.torus-stage .zoomwrap{pointer-events:none;position:absolute;inset:0}.torus-stage.shown .zoomwrap{opacity:0;transition:opacity 0s .5s}.torus-stage 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0;scroll-margin-top:1.5rem;display:grid}.torus-stage .chapter .fig{aspect-ratio:1}.torus-stage .text{border:1px solid color-mix(in srgb, var(--c) 16%, transparent);background:var(--pane);backdrop-filter:blur(3px);border-radius:1.25rem;padding:1.5rem 1.7rem 1.6rem;font-size:1.05rem;line-height:1.7}.torus-stage .text .num{color:var(--c);letter-spacing:.12em;text-transform:uppercase;font-size:.95rem;font-weight:600}.torus-stage .text h3{margin:.2rem 0 .6rem;font-size:1.45rem;font-weight:500;line-height:1.3}.torus-stage .text p{margin:0}.torus-stage .text.math i{font-family:Georgia,Times New Roman,serif;font-size:1.06em}.torus-stage .act{cursor:pointer;border:1px solid color-mix(in srgb, var(--c) 50%, transparent);background:color-mix(in srgb, var(--chip) 30%, transparent);color:var(--fg);font:inherit;border-radius:999px;margin-top:1rem;padding:.45rem 1rem;font-size:.92rem}.torus-stage .act:hover{border-color:var(--c)}.torus-stage 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transparent);backdrop-filter:blur(8px);border-radius:1rem;padding:.6rem 1.3rem .7rem;transition:opacity .3s,transform .3s;position:absolute;bottom:1.4rem;left:50%;transform:translate(-50%,.6rem)}.torus-stage .toast.on{opacity:1;transform:translate(-50%)}.torus-stage .toast .chord{font-size:1.3rem;font-weight:400}.torus-stage .toast .notes{color:var(--muted);letter-spacing:.08em}.torus-stage .toast .move{color:var(--c);font-size:.95rem}.torus-stage .tip{z-index:1;pointer-events:none;white-space:nowrap;background:var(--pop);border:1px solid var(--chip-edge);opacity:0;border-radius:.5rem;padding:.2rem .6rem;font-size:.9rem;transition:opacity .15s;position:fixed;transform:translate(14px,-50%)}.torus-stage .tip.on{opacity:1}@media (width<=1100px){.torus-stage .chapter{grid-template-columns:minmax(0,40rem);justify-content:center;gap:1.25rem}}@media (width<=760px){.torus-stage .story-inner{padding-top:4rem}.torus-stage .chapter{gap:1rem;margin:3.5rem 0}.torus-stage .fig.hero{height:52vh}.torus-stage .text{padding:1.2rem 1.25rem 1.3rem}.torus-stage .bar button{height:2.4rem;padding:0 .8rem;font-size:.85rem}.torus-stage .bar .close{width:2.4rem}}