:root{--bg:#0b1220;--card:#121a2b;--text:#e8eefc;--muted:#a8b3cf;--accent:#69a7ff;--good:#2ecc71;--bad:#ff5a6b;}
*{box-sizing:border-box;font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;}
body{margin:0;background:linear-gradient(180deg,#070b14,#0b1220);color:var(--text);}
.container{max-width:980px;margin:0 auto;padding:28px 16px 60px;}
.header{margin-bottom:18px;}
.title{margin:0 0 6px;font-size:26px;line-height:1.2;}
.sub{color:var(--muted);font-size:14px;}
.quiz{display:flex;flex-direction:column;gap:14px;}
.q{background:rgba(18,26,43,.9);border:1px solid rgba(105,167,255,.15);border-radius:14px;padding:14px;}
.q.correct{border-color:rgba(46,204,113,.55);box-shadow:0 0 0 2px rgba(46,204,113,.12) inset;}
.q.incorrect{border-color:rgba(255,90,107,.6);box-shadow:0 0 0 2px rgba(255,90,107,.12) inset;}
.qhead{display:flex;gap:10px;margin-bottom:10px;}
.qnum{font-weight:700;color:var(--accent);min-width:26px;}
.qprompt{font-size:15px;line-height:1.35;}
.qimg{width:100%;max-height:520px;object-fit:contain;background:#050814;border-radius:12px;border:1px solid rgba(255,255,255,.08);margin:10px 0 8px;}
.opts{display:grid;grid-template-columns:1fr;gap:8px;margin-top:6px;}
.opt{display:flex;gap:10px;align-items:flex-start;padding:10px;border-radius:12px;border:1px solid rgba(255,255,255,.08);background:rgba(5,8,20,.45);cursor:pointer;}
.opt:hover{border-color:rgba(105,167,255,.35);}
.opt input{margin-top:2px;}
.opttext{line-height:1.25;}
.actions{display:flex;gap:10px;align-items:center;margin-top:8px;}
.btn{background:var(--accent);border:none;color:#071225;padding:10px 14px;border-radius:12px;font-weight:700;cursor:pointer;}
.btn.secondary{background:transparent;border:1px solid rgba(105,167,255,.35);color:var(--text);}
.result{margin-top:10px;color:var(--text);font-size:16px;}
.exp{margin-top:10px;}
.exp summary{cursor:pointer;color:var(--muted);}
.expbody{margin-top:8px;color:var(--text);line-height:1.35;}
.muted{color:var(--muted);}
.why{margin-top:6px;}