:root{--bg: #0f1020;--surface: #191a2e;--surface-raised: #222442;--border: #2e3157;--text: #eceefb;--muted: #9aa0c9;--accent: #6c63ff;--accent-soft: #6c63ff22;--good: #2fbf71;--good-soft: #2fbf7122;--bad: #ef5b6b;--bad-soft: #ef5b6b22;--radius: 16px;--tap: 48px}*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}html,body{margin:0;height:100%}body{background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,sans-serif;overscroll-behavior-y:none}#root{min-height:100%;display:flex;justify-content:center}.shell{width:100%;max-width:560px;min-height:100dvh;display:flex;flex-direction:column;background:var(--bg);border-left:1px solid transparent;border-right:1px solid transparent}@media(min-width:620px){.shell{border-color:var(--border)}}.topbar{display:flex;align-items:center;gap:12px;padding:14px 18px;border-bottom:1px solid var(--border);position:sticky;top:0;background:color-mix(in srgb,var(--bg) 88%,transparent);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);z-index:10}.brand{font-weight:700;letter-spacing:-.02em;font-size:18px;display:flex;align-items:center;gap:8px}.brand .dot{width:10px;height:10px;border-radius:3px;background:var(--accent);box-shadow:0 0 12px var(--accent)}.spacer{flex:1}.streak{font-size:13px;color:var(--muted);font-variant-numeric:tabular-nums}.content{padding:18px;flex:1;display:flex;flex-direction:column;gap:16px}h1{font-size:24px;margin:0;letter-spacing:-.02em}h2{font-size:17px;margin:0;letter-spacing:-.01em}.sub{color:var(--muted);font-size:14px;line-height:1.5;margin:0}.hero{background:linear-gradient(140deg,var(--accent-soft),transparent 70%);border:1px solid var(--border);border-radius:var(--radius);padding:18px;display:flex;flex-direction:column;gap:10px}.metrics{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.metric{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:12px;text-align:center}.metric b{display:block;font-size:20px;font-variant-numeric:tabular-nums}.metric span{font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em}.level-head{display:flex;align-items:baseline;gap:10px;margin-top:6px}.level-head h2{font-size:13px;text-transform:uppercase;letter-spacing:.1em;color:var(--muted)}.level-head .rule{flex:1;height:1px;background:var(--border)}.lesson{display:flex;gap:14px;align-items:center;width:100%;text-align:left;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:14px;color:inherit;font:inherit;cursor:pointer;min-height:var(--tap);transition:transform .12s ease,border-color .12s ease}.lesson:active{transform:scale(.985);border-color:var(--accent)}.lesson-body{flex:1;min-width:0}.lesson-title{font-weight:600;font-size:15px;margin-bottom:3px}.lesson-goal{font-size:13px;color:var(--muted);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.ring{width:40px;height:40px;flex:0 0 40px;border-radius:50%;display:grid;place-items:center;font-size:12px;font-weight:700;font-variant-numeric:tabular-nums;border:3px solid var(--border);color:var(--muted)}.ring.done{border-color:var(--good);color:var(--good)}.ring.partial{border-color:var(--accent);color:var(--accent)}.badge{font-size:10px;font-weight:700;letter-spacing:.08em;color:var(--accent);background:var(--accent-soft);border-radius:6px;padding:3px 7px}.progress-track{height:5px;background:var(--surface-raised);border-radius:3px;overflow:hidden;flex:0 0 auto}.progress-track i{display:block;height:100%;background:var(--accent);transition:width .25s ease}.q-prompt{font-size:20px;font-weight:600;line-height:1.35}.q-context{font-family:ui-monospace,SF Mono,Menlo,monospace;font-size:14px;color:var(--muted);background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:10px 12px}.q-count{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}.option{display:flex;align-items:center;gap:12px;width:100%;text-align:left;background:var(--surface);border:1.5px solid var(--border);border-radius:14px;padding:14px;min-height:var(--tap);color:inherit;font:inherit;font-size:15px;cursor:pointer;transition:border-color .12s ease,background .12s ease}.option:active{transform:scale(.99)}.option .key{width:26px;height:26px;flex:0 0 26px;border-radius:8px;background:var(--surface-raised);display:grid;place-items:center;font-size:12px;font-weight:700;color:var(--muted)}.option.sel{border-color:var(--accent);background:var(--accent-soft)}.option.right{border-color:var(--good);background:var(--good-soft)}.option.wrong{border-color:var(--bad);background:var(--bad-soft)}.option.right .key,.option.wrong .key{color:inherit;background:transparent}.option:disabled{cursor:default}.explain{border-left:3px solid var(--accent);padding:4px 0 4px 12px;font-size:14px;line-height:1.5;color:var(--text)}.tip{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:14px;font-size:14px;line-height:1.55}.tip b{display:block;font-size:11px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:6px}.footer{position:sticky;bottom:0;padding:14px 18px calc(14px + env(safe-area-inset-bottom));border-top:1px solid var(--border);background:color-mix(in srgb,var(--bg) 92%,transparent);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);display:flex;gap:10px}.btn{flex:1;min-height:var(--tap);border-radius:14px;border:1px solid var(--border);background:var(--surface-raised);color:var(--text);font:inherit;font-size:15px;font-weight:600;cursor:pointer;display:flex;align-items:center;justify-content:center;gap:8px;transition:opacity .12s ease,transform .12s ease}.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}.btn.ghost{background:transparent;flex:0 0 auto;padding:0 16px}.btn:active:not(:disabled){transform:scale(.985)}.btn:disabled{opacity:.4;cursor:default}.center{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;text-align:center;padding:40px 20px}.score-big{font-size:56px;font-weight:800;letter-spacing:-.04em;font-variant-numeric:tabular-nums;line-height:1}.error{color:var(--bad);font-size:14px}.spin{width:26px;height:26px;border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .7s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}