:root{
  --brand-primary:#1DA083;
  --brand-accent:#FE783D;
  --bg:#0f1216;
  --card:#151a21;
  --text:#e9eef2;
  --muted:#99a3ad;
  --success:#1DB954;
  --error:#ff4d4f;
  --border:#263140;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial;
  background:
    radial-gradient(1200px 800px at 20% -10%, rgba(29,160,131,.15), transparent),
    radial-gradient(1200px 800px at 120% 10%, rgba(254,120,61,.12), transparent),
    var(--bg);
  color:var(--text);
  line-height:1.5;
}
.wrap{max-width:920px;padding:24px;margin:0 auto}
header{display:flex;gap:16px;align-items:center;justify-content:space-between;margin-bottom:16px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:12px}
.logo{width:42px;height:42px;border-radius:12px;background:linear-gradient(135deg,var(--brand-primary),var(--brand-accent));box-shadow:0 10px 30px rgba(29,160,131,.35),0 2px 10px rgba(254,120,61,.25)}
h1{font-size:clamp(1.25rem,1.2rem + 1.2vw,1.9rem);margin:0}
.subtitle{color:var(--muted);font-size:.95rem}
.progress{width:100%;height:10px;background:#0d1116;border-radius:999px;overflow:hidden;border:1px solid var(--border);max-width:340px;min-width:220px}
.bar{height:100%;width:0;background:linear-gradient(90deg,var(--brand-primary),var(--brand-accent));transition:width .3s ease}
.card{background:linear-gradient(180deg,rgba(255,255,255,.02),rgba(255,255,255,0));border:1px solid var(--border);border-radius:18px;padding:clamp(16px,2vw,24px);margin-top:16px;box-shadow:0 10px 40px rgba(0,0,0,.25)}
.meta{display:flex;align-items:center;justify-content:space-between;gap:8px;color:var(--muted);font-size:.95rem;margin-bottom:10px;flex-wrap:wrap}
.question{--qsize:clamp(1.1rem,1rem + .8vw,1.5rem);font-size:var(--qsize);line-height:1.3;min-height:calc(var(--qsize)*2.6);font-weight:600;margin-bottom:12px}
.options{display:grid;grid-template-columns:1fr;gap:10px}
@media(min-width:720px){.options{grid-template-columns:1fr 1fr}}
.option{border:1px solid var(--border);background:#0d1116;color:var(--text);border-radius:14px;padding:14px;cursor:pointer;text-align:left;transition:transform .12s ease,border-color .2s ease,background .2s ease,box-shadow .2s ease;position:relative;outline:none}
.option:hover{transform:translateY(-1px);border-color:#334155}
.option.selected.correct{border-color:var(--brand-primary);box-shadow:0 0 0 3px rgba(29,160,131,.2) inset}
.option.selected.wrong{border-color:var(--error);box-shadow:0 0 0 3px rgba(255,77,79,.18) inset}
.option[disabled]{opacity:.9;cursor:not-allowed}
.explain{margin-top:20px;padding:12px 14px;border-radius:12px;background:rgba(29,160,131,.08);border:1px solid rgba(29,160,131,.25);display:none;font-size:.98rem;min-height:2.2em}
.explain.show{display:block}
.controls{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-top:12px;flex-wrap:wrap}
.btn{background:linear-gradient(135deg,var(--brand-primary),var(--brand-accent));color:#0b0d0f;border:none;padding:12px 16px;border-radius:12px;font-weight:700;cursor:pointer;letter-spacing:.2px;transition:transform .12s ease,filter .12s ease}
.btn:hover{transform:translateY(-1px);filter:brightness(1.05)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn-outline{background:#0d1116;color:var(--text);border:1px solid var(--border)}
.score{font-weight:700;color:var(--muted)}
footer{margin-top:28px;color:var(--muted);font-size:.9rem;text-align:center}
.result{text-align:center;display:none}
.result h2{font-size:clamp(1.3rem,1rem + 1.4vw,2rem);margin-bottom:6px}
.badge{display:inline-block;margin-top:8px;padding:8px 12px;border-radius:999px;border:1px solid var(--border);background:#0d1116}
.share{margin-top:18px;display:flex;flex-wrap:wrap;gap:10px;justify-content:center}
.share button{padding:10px 14px;border-radius:10px;border:1px solid var(--border);background:#0d1116;color:var(--text);cursor:pointer}
.share button:hover{border-color:#334155}
.hidden{display:none}
.result-actions{margin-top:14px}
.result-line{margin:6px 0 2px}