:root{--bg:#0b1020;--card:#121a32;--muted:#93a4c3;--text:#eef4ff;--accent:#41d1ff;--good:#34d399;--bad:#fb7185;--warn:#fbbf24;--line:#273553}*{box-sizing:border-box}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;background:radial-gradient(circle at top left,#19325f 0,#0b1020 42rem);color:var(--text);min-height:100vh}.topbar{display:flex;justify-content:space-between;gap:1rem;align-items:flex-start;padding:1.4rem clamp(1rem,4vw,3rem)}h1,h2,h3,p{margin:0}h1{font-size:clamp(1.6rem,4vw,2.6rem)}p{color:var(--muted);margin-top:.35rem}.layout{display:grid;grid-template-columns:minmax(0,1fr) 360px;gap:1.2rem;padding:0 clamp(1rem,4vw,3rem) 1.5rem}.card{background:rgba(18,26,50,.88);border:1px solid var(--line);border-radius:24px;box-shadow:0 20px 60px rgba(0,0,0,.25)}.quiz-card{padding:1.2rem;min-height:70vh}.quiz-head{display:flex;justify-content:space-between;align-items:start;gap:1rem}.pill{display:inline-flex;border:1px solid #2d87a9;background:#0b2438;color:#a8ecff;border-radius:999px;padding:.25rem .65rem;font-size:.85rem;margin-bottom:.5rem}.star{font-size:2rem;line-height:1;background:transparent;color:var(--warn);border:0;cursor:pointer}.star.on{filter:drop-shadow(0 0 10px rgba(251,191,36,.75))}.sign-frame{display:grid;place-items:center;background:#eaf0f8;border-radius:20px;min-height:390px;margin:1rem 0;padding:1rem}.sign-frame img{max-width:100%;max-height:410px;object-fit:contain}.choices{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.75rem}.choices button,.filters button,.actions button,.ghost{border:1px solid var(--line);background:#17213f;color:var(--text);padding:.85rem 1rem;border-radius:14px;font-weight:700;cursor:pointer;text-align:left}.choices button:hover,.filters button:hover,.actions button:hover,.ghost:hover{border-color:var(--accent)}.choices button.correct{background:rgba(52,211,153,.18);border-color:var(--good)}.choices button.wrong{background:rgba(251,113,133,.18);border-color:var(--bad)}.feedback{min-height:3rem;margin:.9rem 0;color:var(--muted);font-size:1.05rem}.feedback.good{color:var(--good)}.feedback.bad{color:var(--bad)}.actions{display:flex;flex-wrap:wrap;gap:.7rem}.actions button,#nextBtn{background:linear-gradient(135deg,#22d3ee,#2563eb);border:0;color:white;text-align:center}.actions .secondary{background:#17213f;border:1px solid var(--line)}.ghost{background:transparent;text-align:center}.side{padding:1.1rem;align-self:start;position:sticky;top:1rem}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:.6rem;margin:1rem 0}.stats div{background:#0d1429;border:1px solid var(--line);border-radius:16px;padding:.8rem;text-align:center}.stats strong{display:block;font-size:1.6rem}.stats span{color:var(--muted);font-size:.85rem}.filters{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:1rem}.filters button{padding:.55rem .75rem;font-size:.9rem}.filters .active{border-color:var(--accent);background:#0b2438}.learn-list{max-height:360px;overflow:auto;display:grid;gap:.5rem}.learn-item{display:flex;justify-content:space-between;gap:.75rem;align-items:center;border:1px solid var(--line);border-radius:14px;padding:.6rem;background:#0d1429}.learn-item button{border:0;background:transparent;color:var(--accent);font-weight:800;cursor:pointer}footer{padding:0 clamp(1rem,4vw,3rem) 2rem;color:var(--muted)}@media(max-width:900px){.layout{grid-template-columns:1fr}.side{position:static}.choices{grid-template-columns:1fr}.topbar{flex-direction:column}.sign-frame{min-height:280px}}