:root{--bg: #0b0d13;--bg-2: #11141d;--surface: #161a25;--surface-2: #1c2130;--border: #262c3b;--border-soft: #20242f;--text: #e7ebf3;--text-dim: #9aa4b8;--text-faint: #6b7488;--brand: #6366f1;--brand-2: #8b5cf6;--good: #22c55e;--again: #ef4444;--hard: #f59e0b;--easy: #38bdf8;--radius: 16px;--radius-sm: 10px;--shadow: 0 10px 40px -12px rgba(0, 0, 0, .6);--font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;--accent: var(--brand)}*{box-sizing:border-box}html,body,#root{height:100%;margin:0}body{font-family:var(--font);color:var(--text);background:radial-gradient(1200px 600px at 80% -10%,rgba(99,102,241,.12),transparent 60%),radial-gradient(900px 500px at -10% 10%,rgba(139,92,246,.1),transparent 55%),var(--bg);-webkit-font-smoothing:antialiased;line-height:1.55}button{font-family:inherit;cursor:pointer}code{font-family:ui-monospace,SF Mono,Menlo,Consolas,monospace;background:var(--surface-2);padding:1px 6px;border-radius:6px;font-size:.9em}kbd{font-family:ui-monospace,SF Mono,Menlo,Consolas,monospace;font-size:.72rem;background:var(--surface-2);border:1px solid var(--border);border-bottom-width:2px;border-radius:6px;padding:1px 6px;color:var(--text-dim)}.app{min-height:100%;display:flex;flex-direction:column}.topbar{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;padding:14px clamp(16px,4vw,40px);background:#0b0d13cc;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--border)}.topbar__brand{background:none;border:none;color:var(--text);font-size:1.2rem;font-weight:800;letter-spacing:-.02em}.topbar__brand span{color:var(--brand)}.topbar__nav{display:flex;align-items:center;gap:8px}.topbar__due{font-size:.78rem;font-weight:600;color:var(--hard);background:#f59e0b1f;border:1px solid rgba(245,158,11,.3);padding:4px 10px;border-radius:999px}.topbar__link{background:none;border:none;color:var(--text-dim);font-size:.9rem;font-weight:600;padding:6px 10px;border-radius:8px}.topbar__link:hover{color:var(--text);background:var(--surface)}.topbar__link.is-active{color:var(--text);background:var(--surface-2)}.content{flex:1;width:100%;max-width:1040px;margin:0 auto;padding:clamp(20px,4vw,44px) clamp(16px,4vw,40px)}.footer{text-align:center;color:var(--text-faint);font-size:.8rem;padding:20px;border-top:1px solid var(--border)}.empty{text-align:center;padding:80px 20px;color:var(--text-dim)}.loading{display:flex;flex-direction:column;align-items:center;gap:16px;padding:100px 20px;color:var(--text-dim)}.loading__spinner{width:38px;height:38px;border-radius:50%;border:3px solid var(--surface-2);border-top-color:var(--brand);animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.btn{border:1px solid var(--border);background:var(--surface);color:var(--text);padding:10px 18px;border-radius:var(--radius-sm);font-size:.92rem;font-weight:600;transition:transform .08s ease,background .15s ease,border-color .15s ease}.btn:hover{background:var(--surface-2)}.btn:active{transform:translateY(1px)}.btn:disabled{opacity:.4;cursor:not-allowed}.btn--primary{background:linear-gradient(135deg,var(--brand),var(--brand-2));border-color:transparent;color:#fff;box-shadow:0 8px 24px -10px var(--brand)}.btn--primary:hover{filter:brightness(1.08);background:linear-gradient(135deg,var(--brand),var(--brand-2))}.btn--lg{padding:14px 28px;font-size:1rem}.btn--ghost{background:transparent}.btn--danger-ghost{background:transparent;border-color:#ef444466;color:#fca5a5}.btn--danger-ghost:hover{background:#ef44441a}.btn--reveal{width:100%;padding:16px;margin-top:8px;background:var(--surface-2);border-style:dashed;display:flex;align-items:center;justify-content:center;gap:10px;font-size:1rem}.btn--reveal:hover{border-color:var(--accent);color:#fff}.home__hero{text-align:center;margin-bottom:36px}.home__hero h1{font-size:clamp(2.4rem,6vw,3.4rem);margin:0 0 8px;letter-spacing:-.03em;font-weight:800}.home__hero-accent{background:linear-gradient(135deg,var(--brand),var(--brand-2));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}.home__tagline{color:var(--text-dim);max-width:540px;margin:0 auto;font-size:1.02rem}.home__section-head{display:flex;align-items:center;justify-content:space-between;margin:0 0 14px}.home__section-head h2{font-size:1.05rem;margin:0;color:var(--text-dim);text-transform:uppercase;letter-spacing:.06em;font-weight:700}.home__chip-actions{display:flex;gap:8px}.category-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px;margin-bottom:36px}.cat-card{text-align:left;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:16px;display:flex;flex-direction:column;gap:6px;position:relative;overflow:hidden;transition:border-color .15s ease,transform .1s ease,background .15s ease}.cat-card:before{content:"";position:absolute;inset:0 auto 0 0;width:3px;background:var(--accent);opacity:.5}.cat-card:hover:not(:disabled){transform:translateY(-2px);border-color:var(--accent)}.cat-card--on{background:color-mix(in srgb,var(--accent) 14%,var(--surface));border-color:var(--accent)}.cat-card--off{opacity:.45;cursor:not-allowed}.cat-card__top{display:flex;align-items:center;justify-content:space-between}.cat-card__dot{width:10px;height:10px;border-radius:50%;background:var(--accent);box-shadow:0 0 12px var(--accent)}.cat-card__count{font-size:.78rem;font-weight:700;color:var(--text-dim);background:var(--bg-2);padding:2px 9px;border-radius:999px}.cat-card__label{font-size:1.02rem;margin:2px 0 0;font-weight:700}.cat-card__blurb{font-size:.82rem;color:var(--text-faint);margin:0}.cat-card__mastered{font-size:.72rem;color:var(--good);font-weight:600;margin-top:2px}.home__controls{display:flex;flex-wrap:wrap;gap:28px;padding:22px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);margin-bottom:22px}.control{display:flex;flex-direction:column;gap:10px}.control__label{font-size:.74rem;text-transform:uppercase;letter-spacing:.07em;color:var(--text-faint);font-weight:700}.control__options{display:flex;gap:8px;flex-wrap:wrap}.chip{background:var(--surface-2);border:1px solid var(--border);color:var(--text-dim);padding:7px 14px;border-radius:999px;font-size:.85rem;font-weight:600;text-transform:capitalize;transition:all .12s ease}.chip:hover{color:var(--text);border-color:var(--text-faint)}.chip--active{background:var(--brand);border-color:var(--brand);color:#fff}.chip--easy.chip--active{background:var(--good);border-color:var(--good)}.chip--medium.chip--active{background:var(--hard);border-color:var(--hard)}.chip--hard.chip--active{background:var(--again);border-color:var(--again)}.home__launch{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;padding:20px 22px;background:linear-gradient(135deg,#6366f11f,#8b5cf614);border:1px solid var(--border);border-radius:var(--radius)}.home__pool{display:flex;gap:18px;flex-wrap:wrap}.home__pool-item{font-size:.9rem;color:var(--text-dim)}.home__pool-item strong{color:var(--text);font-size:1.05rem}.home__pool-item--due strong{color:var(--hard)}.home__pool-item--new strong{color:var(--easy)}.home__launch-actions{display:flex;gap:10px}.study{max-width:720px;margin:0 auto}.study__bar{display:flex;align-items:center;gap:16px;margin-bottom:22px}.study__progress{flex:1;display:flex;align-items:center;gap:12px}.progress{flex:1;height:8px;background:var(--surface-2);border-radius:999px;overflow:hidden}.progress__fill{height:100%;background:linear-gradient(90deg,var(--brand),var(--brand-2));transition:width .3s ease}.study__count{font-size:.8rem;color:var(--text-dim);font-variant-numeric:tabular-nums;white-space:nowrap}.study__stats{display:flex;gap:6px}.study__hint{text-align:center;color:var(--text-faint);font-size:.82rem;margin-top:18px}.pill{font-size:.76rem;font-weight:700;padding:3px 9px;border-radius:999px;white-space:nowrap}.pill--good{color:var(--good);background:#22c55e1f}.pill--again{color:var(--again);background:#ef44441f}.pill--hard{color:var(--hard);background:#f59e0b1f}.pill--easy{color:var(--easy);background:#38bdf81f}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:clamp(20px,4vw,32px);box-shadow:var(--shadow);position:relative;overflow:hidden;animation:card-in .25s ease}.card:before{content:"";position:absolute;inset:0 0 auto 0;height:4px;background:var(--accent)}@keyframes card-in{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}.card__meta{display:flex;flex-wrap:wrap;gap:7px;margin-bottom:18px}.badge{font-size:.72rem;font-weight:700;padding:3px 10px;border-radius:999px;text-transform:capitalize}.badge--category{background:color-mix(in srgb,var(--accent) 22%,transparent);color:color-mix(in srgb,var(--accent) 80%,white);border:1px solid color-mix(in srgb,var(--accent) 40%,transparent)}.badge--diff{border:1px solid var(--border);color:var(--text-dim);background:var(--surface-2)}.badge--easy{color:var(--good)}.badge--medium{color:var(--hard)}.badge--hard{color:var(--again)}.badge--tag{background:var(--bg-2);color:var(--text-faint)}.card__label{font-size:.7rem;text-transform:uppercase;letter-spacing:.08em;color:var(--text-faint);font-weight:700;margin:0 0 6px}.card__question h2{font-size:clamp(1.2rem,3vw,1.5rem);line-height:1.4;margin:0 0 4px;font-weight:700}.card__reveal{margin-top:22px;animation:card-in .2s ease}.card__answer{padding:16px;background:color-mix(in srgb,var(--good) 8%,var(--surface-2));border:1px solid color-mix(in srgb,var(--good) 25%,transparent);border-radius:var(--radius-sm);margin-bottom:14px}.card__answer-text{margin:0;font-size:1.05rem;font-weight:600}.card__explanation{padding:16px;background:var(--bg-2);border:1px solid var(--border);border-radius:var(--radius-sm)}.card__explanation p:last-child{margin:0;color:var(--text-dim);font-size:.95rem;line-height:1.65}.rate{margin-top:22px}.rate__prompt{text-align:center;color:var(--text-dim);font-size:.85rem;margin:0 0 12px}.rate__buttons{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.rate__btn{display:flex;flex-direction:column;align-items:center;gap:3px;padding:12px 6px;border-radius:var(--radius-sm);border:1px solid var(--border);background:var(--surface-2)}.rate__btn-key{font-size:.68rem;color:var(--text-faint);border:1px solid var(--border);border-radius:5px;width:18px;height:18px;display:grid;place-items:center}.rate__btn-label{font-weight:700;font-size:.95rem}.rate__btn-interval{font-size:.72rem;color:var(--text-faint);font-variant-numeric:tabular-nums}.rate__btn--again:hover{border-color:var(--again);background:#ef44441f}.rate__btn--hard:hover{border-color:var(--hard);background:#f59e0b1f}.rate__btn--good:hover{border-color:var(--good);background:#22c55e1f}.rate__btn--easy:hover{border-color:var(--easy);background:#38bdf81f}.badge--type{background:color-mix(in srgb,var(--brand) 20%,transparent);color:color-mix(in srgb,var(--brand) 85%,white);border:1px solid color-mix(in srgb,var(--brand) 45%,transparent)}.mcq{margin-top:20px}.mcq__options{display:flex;flex-direction:column;gap:10px}.mcq__option{display:flex;align-items:center;gap:12px;text-align:left;width:100%;padding:14px 16px;border-radius:var(--radius-sm);border:1px solid var(--border);background:var(--surface-2);color:var(--text);font-size:.97rem;transition:border-color .12s ease,background .12s ease,transform .08s ease}.mcq__option:not(:disabled):hover{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 10%,var(--surface-2))}.mcq__option:not(:disabled):active{transform:translateY(1px)}.mcq__option:disabled{cursor:default}.mcq__letter{flex:none;width:28px;height:28px;display:grid;place-items:center;border-radius:8px;background:var(--bg-2);border:1px solid var(--border);font-weight:700;font-size:.85rem;color:var(--text-dim)}.mcq__text{flex:1}.mcq__mark{flex:none;font-weight:800}.mcq__mark--ok{color:var(--good)}.mcq__mark--no{color:var(--again)}.mcq__option--correct{border-color:var(--good);background:#22c55e24}.mcq__option--correct .mcq__letter{background:var(--good);border-color:var(--good);color:#06240f}.mcq__option--wrong{border-color:var(--again);background:#ef444424}.mcq__option--wrong .mcq__letter{background:var(--again);border-color:var(--again);color:#2b0707}.mcq__option--idle{opacity:.5}.mcq__result{font-weight:700;font-size:1rem;margin:0 0 14px}.mcq__result--right{color:var(--good)}.mcq__result--wrong{color:var(--again)}.mcq__continue{width:100%;margin-top:4px;display:flex;align-items:center;justify-content:center;gap:8px}.summary{display:grid;place-items:center;padding:20px 0}.summary__card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:clamp(24px,5vw,40px);max-width:480px;width:100%;text-align:center;box-shadow:var(--shadow)}.summary__card h2{margin:0 0 4px;font-size:1.6rem}.summary__message{color:var(--text-dim);margin:0 0 24px}.summary__score{display:grid;place-items:center;margin-bottom:24px}.summary__ring{width:150px;height:150px;border-radius:50%;display:grid;place-items:center;background:radial-gradient(closest-side,var(--surface) 78%,transparent 79% 100%),conic-gradient(var(--brand) calc(var(--pct) * 1%),var(--surface-2) 0)}.summary__ring-value{font-size:2rem;font-weight:800}.summary__ring-label{font-size:.75rem;color:var(--text-faint);text-transform:uppercase;letter-spacing:.08em}.summary__grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-bottom:20px}.summary__stat{background:var(--bg-2);border-radius:var(--radius-sm);padding:14px 8px}.summary__stat-num{display:block;font-size:1.6rem;font-weight:800}.summary__stat--again .summary__stat-num{color:var(--again)}.summary__stat--good .summary__stat-num{color:var(--good)}.summary__stat-label{font-size:.75rem;color:var(--text-faint)}.summary__breakdown{display:flex;justify-content:center;gap:8px;flex-wrap:wrap;margin-bottom:24px}.summary__actions{display:flex;gap:10px;justify-content:center}.stats__head{display:flex;align-items:center;justify-content:space-between;margin-bottom:24px}.stats__head h2{margin:0;font-size:1.5rem}.stats__overview{display:grid;grid-template-columns:repeat(auto-fit,minmax(120px,1fr));gap:12px;margin-bottom:36px}.stat-tile{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:18px;text-align:center}.stat-tile--accent{background:linear-gradient(135deg,#22c55e24,#22c55e0a);border-color:#22c55e4d}.stat-tile__num{display:block;font-size:1.9rem;font-weight:800;letter-spacing:-.02em}.stat-tile__label{font-size:.78rem;color:var(--text-faint)}.stats__subhead{font-size:.9rem;text-transform:uppercase;letter-spacing:.06em;color:var(--text-dim);margin:0 0 16px}.stats__categories{display:flex;flex-direction:column;gap:14px}.cat-progress{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-sm);padding:14px 16px}.cat-progress__head{display:flex;justify-content:space-between;margin-bottom:8px;font-size:.88rem}.cat-progress__name{font-weight:600}.cat-progress__nums{color:var(--text-faint);font-size:.8rem}.cat-progress__bar{position:relative;height:8px;background:var(--surface-2);border-radius:999px;overflow:hidden}.cat-progress__seen{position:absolute;inset:0 auto 0 0;background:color-mix(in srgb,var(--accent) 35%,transparent)}.cat-progress__mastered{position:absolute;inset:0 auto 0 0;background:var(--accent)}.stats__footer{margin-top:36px;text-align:center}@media (max-width: 560px){.rate__buttons{grid-template-columns:repeat(2,1fr)}.home__launch{flex-direction:column;align-items:stretch}.home__launch-actions{justify-content:stretch}.home__launch-actions .btn{flex:1}.summary__actions{flex-direction:column}}