:root{--bg: #f4f5f7;--surface: #ffffff;--text: #1c1d21;--muted: #6b7280;--border: #e3e5e9;--primary: #4f46e5;--primary-ink: #ffffff;--right: #16a34a;--wrong: #dc2626;--badge: #eef2ff;--badge-ink: #4338ca;--radius: 14px;--shadow: 0 1px 3px rgba(0, 0, 0, .08), 0 1px 2px rgba(0, 0, 0, .04)}@media (prefers-color-scheme: dark){:root{--bg: #16171b;--surface: #212227;--text: #eceef2;--muted: #9aa0ab;--border: #33353c;--primary: #6366f1;--badge: #2a2b52;--badge-ink: #c7cbff;--shadow: none}}*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text);line-height:1.5}a{color:var(--primary);text-decoration:none}h1{font-size:1.5rem;margin:.2em 0 .6em}h2{font-size:1.2rem;margin:0 0 .5em}.container{max-width:900px;margin:0 auto;padding:16px 16px calc(32px + env(safe-area-inset-bottom))}.appbar{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;padding:12px 16px;padding-top:calc(12px + env(safe-area-inset-top));background:var(--surface);border-bottom:1px solid var(--border)}.brand{font-weight:700;font-size:1.05rem;color:var(--text)}.appbar-right{display:flex;align-items:center;gap:10px}.who{color:var(--muted);font-size:.85rem;max-width:40vw;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:16px;margin-bottom:14px}.muted{color:var(--muted)}.small{font-size:.85rem}.empty{padding:24px 0;text-align:center}.center{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:10px;min-height:40vh;text-align:center}.row-between{display:flex;align-items:center;justify-content:space-between;gap:10px}.crumbs{margin-bottom:6px}.error{color:var(--wrong);font-size:.9rem}button,.btn-primary,.btn-ghost{font:inherit;cursor:pointer}.btn-primary{display:inline-flex;align-items:center;justify-content:center;gap:8px;background:var(--primary);color:var(--primary-ink);border:none;border-radius:10px;padding:10px 16px;font-weight:600;min-height:44px}.btn-primary[aria-disabled=true]{opacity:.45;pointer-events:none}.btn-ghost{background:transparent;color:var(--text);border:1px solid var(--border);border-radius:10px;padding:9px 14px;min-height:44px}.btn-ghost.danger{color:var(--wrong);border-color:transparent}button:disabled{opacity:.55;cursor:default}label{display:block;font-size:.9rem;font-weight:600;margin-bottom:4px}input,textarea{width:100%;font:inherit;color:var(--text);background:var(--bg);border:1px solid var(--border);border-radius:10px;padding:10px 12px;margin-bottom:12px}textarea{resize:vertical;font-family:ui-monospace,SFMono-Regular,Menlo,monospace}input:focus,textarea:focus{outline:2px solid var(--primary);outline-offset:1px}.form label,.login label{margin-bottom:10px}.login{width:min(360px,100%)}.login h1{text-align:center}.deck-grid{display:grid;grid-template-columns:1fr;gap:14px}@media (min-width: 640px){.deck-grid{grid-template-columns:1fr 1fr}}.deck-card{margin:0;display:flex;flex-direction:column;gap:8px}.deck-head{display:flex;align-items:center;justify-content:space-between}.deck-title{font-weight:700;font-size:1.1rem;color:var(--text)}.deck-stats{display:flex;align-items:center;gap:10px;font-size:.9rem;color:var(--muted);margin-top:auto}.badge{background:var(--badge);color:var(--badge-ink);border-radius:999px;padding:2px 10px;font-weight:600}.deck-actions{display:flex;gap:8px;flex-wrap:wrap}.card-list{display:flex;flex-direction:column;gap:12px}.card-row{display:grid;grid-template-columns:1fr 1fr;gap:14px}.card-row-actions{grid-column:1 / -1;display:flex;gap:8px;justify-content:flex-end;border-top:1px solid var(--border);padding-top:10px}.card-label{font-size:.75rem;text-transform:uppercase;letter-spacing:.04em;color:var(--muted);margin-bottom:4px}@media (max-width: 560px){.card-row{grid-template-columns:1fr}}.editor-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}@media (max-width: 640px){.editor-grid{grid-template-columns:1fr}}.preview{border:1px dashed var(--border);border-radius:10px;padding:8px 12px;min-height:40px}.file-btn{display:inline-flex;align-items:center}.study-shell{--field: #dfe1e6;--stock: #efe9dc;--stock-edge: #d8cdb6;--ink: #23262d;--ink-soft: #6f6a5d;--rule: #b3352c;--advance: #2f6f5e;--reset: #b3352c;--chrome: #4a4f5a;--hair: #9aa2ae;font-family:ui-monospace,SFMono-Regular,Cascadia Mono,Menlo,monospace}@media (prefers-color-scheme: dark){.study-shell{--field: #14171d;--chrome: #9aa2b0;--hair: #454d59}}.study-shell:before{content:"";position:fixed;top:0;right:0;bottom:0;left:0;z-index:-1;background:var(--field)}.study-shell :focus-visible{outline:2px solid currentColor;outline-offset:2px}.study-bar{display:flex;align-items:baseline;justify-content:space-between;gap:12px;font-size:.7rem;letter-spacing:.12em;text-transform:uppercase;color:var(--chrome);margin-bottom:10px}.study-bar .back{color:var(--chrome);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.study-bar .tally{font-variant-numeric:tabular-nums;white-space:nowrap;flex:none}.session-track{height:2px;background:var(--hair);margin-bottom:22px}.session-track span{display:block;height:100%;background:var(--chrome);transition:width .32s ease-out}.flashcard{background:var(--stock);color:var(--ink);border-radius:2px 12px 12px 2px;border-left:3px solid var(--stock-edge);box-shadow:0 14px 30px #080a0e29;padding:26px 22px 22px;min-height:38vh;display:flex;flex-direction:column;position:relative;cursor:pointer;will-change:transform;transition:transform .3s cubic-bezier(.22,.9,.3,1),opacity .3s ease-out}.flashcard.is-open{touch-action:pan-y;user-select:none;-webkit-user-select:none}.swipe-stamp{position:absolute;top:14px;z-index:3;pointer-events:none;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.72rem;font-weight:700;letter-spacing:.14em;text-transform:uppercase;padding:5px 10px;border-radius:4px;border:2px solid currentColor;background:#efe9dceb}.swipe-stamp.advance{left:18px;color:var(--advance);transform:rotate(-9deg)}.swipe-stamp.reset{right:18px;color:var(--reset);transform:rotate(9deg)}.swipe-tip{margin:10px 0 0;text-align:center;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.62rem;letter-spacing:.06em;color:var(--chrome);opacity:.75}.answer-failed{margin:10px 0 0;text-align:center;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.66rem;line-height:1.5;letter-spacing:.04em;color:var(--reset)}.flashcard .face{flex:0 0 auto}.flashcard .markdown{font-family:ui-serif,Georgia,Iowan Old Style,Palatino Linotype,serif;font-size:clamp(1.15rem,1.02rem + .8vw,1.45rem);line-height:1.5}.flashcard .markdown pre{background:#23262d0f}.flashcard .markdown th,.flashcard .markdown td{border-color:var(--stock-edge)}.head-rule{width:100%;border:none;border-top:1.5px solid var(--rule);opacity:.5;margin:20px 0 0}.flashcard.is-open .head-rule{margin-bottom:20px}.flashcard .back{color:var(--ink)}.flashcard.is-clear{cursor:default;align-items:flex-start;justify-content:center;gap:10px;min-height:34vh}.clear-line{font-family:ui-serif,Georgia,serif;font-size:1.5rem;margin:0}.clear-note{font-family:ui-serif,Georgia,Iowan Old Style,serif;color:var(--ink-soft);font-size:.95rem;line-height:1.55;margin:0 0 6px;max-width:34ch}.ladder{margin:0 2px 20px}.ladder-rail{position:relative;display:grid;grid-template-columns:repeat(5,1fr);align-items:center;height:30px}.ladder-rail:before{content:"";position:absolute;top:50%;left:10%;right:10%;height:1px;background:var(--hair)}.station{position:relative;z-index:2;justify-self:center;text-align:center;font-size:.78rem;font-weight:600;font-variant-numeric:tabular-nums;color:var(--chrome);background:var(--field);padding:0 9px}.station.is-here{background:transparent;color:var(--chrome)}.ladder.is-moved .station.is-here{color:var(--stock)}.traveller{position:absolute;z-index:1;top:50%;width:26px;height:26px;margin-left:-13px;margin-top:-13px;border-radius:50%;background:transparent;border:2px solid var(--chrome);transition:left .42s cubic-bezier(.22,.9,.3,1),background-color .2s ease-out,border-color .2s ease-out}.traveller.moved-up{background:var(--advance);border-color:var(--advance)}.traveller.moved-down{background:var(--reset);border-color:var(--reset)}.ladder-labels{display:grid;grid-template-columns:repeat(5,1fr);margin-top:7px}.interval{text-align:center;font-size:.62rem;letter-spacing:.06em;color:var(--chrome);opacity:.5}.interval.is-here{opacity:1}@media (prefers-reduced-motion: reduce){.traveller,.session-track span,.flashcard{transition:none}}.study-foot{position:sticky;bottom:0;z-index:4;background:var(--field);margin-top:22px;padding-bottom:calc(6px + env(safe-area-inset-bottom))}.study-foot:before{content:"";position:absolute;left:0;right:0;top:-20px;height:20px;background:linear-gradient(to top,var(--field),transparent);pointer-events:none}.study-controls{margin-top:auto}.wide{width:100%}.answer-row{display:grid;grid-template-columns:1fr 1fr;gap:10px}.btn-stock,.btn-reset,.btn-advance{font:inherit;font-size:.82rem;font-weight:600;letter-spacing:.06em;border:none;border-radius:8px;padding:14px;min-height:52px;color:var(--stock);display:inline-flex;align-items:center;justify-content:center;gap:9px;cursor:pointer}.btn-stock{background:var(--ink)}.btn-reset{background:var(--reset)}.btn-advance{background:var(--advance)}.flashcard.is-clear .btn-stock{padding:12px 18px;min-height:44px}.study-shell button:disabled{opacity:.7;cursor:default}.study-shell kbd{font-family:inherit;font-size:.68rem;font-weight:600;background:#ffffff29;border-radius:4px;padding:2px 6px}kbd{font-family:ui-monospace,monospace;font-size:.72rem;background:#0000002e;border-radius:5px;padding:1px 6px;font-weight:600}.markdown :first-child{margin-top:0}.markdown :last-child{margin-bottom:0}.markdown img{max-width:100%;height:auto;border-radius:8px}.markdown pre{background:var(--bg);padding:10px;border-radius:8px;overflow-x:auto}.markdown code{font-family:ui-monospace,monospace;font-size:.9em}.markdown table{border-collapse:collapse}.markdown th,.markdown td{border:1px solid var(--border);padding:4px 8px}