:root{
  font-family:Inter,system-ui,-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo","Noto Sans KR",sans-serif;
  color:#111827;
  background:#f3f4f6;
  --correct:#15803d;
  --correct-bg:#ecfdf3;
  --correct-border:#22c55e;
  --wrong:#dc2626;
  --wrong-bg:#fef2f2;
  --wrong-border:#ef4444;
}
*{box-sizing:border-box}
body{margin:0;background:#f3f4f6}
button,input,textarea,select{font:inherit}
button{cursor:pointer}
.shell{max-width:820px;margin:0 auto;padding:20px 16px 48px}
.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:16px}
h1{font-size:24px;margin:0}
h2{margin-top:0}
.sub,.muted,.note{color:#6b7280}
.sub{margin:.3rem 0 0}
.note{font-size:13px;line-height:1.5}
.card,.stats{background:white;border:1px solid #e5e7eb;border-radius:20px;box-shadow:0 10px 28px rgba(17,24,39,.06)}
.card{padding:22px;margin-bottom:14px}
.card.compact{padding:14px 18px}
.stats{display:grid;grid-template-columns:repeat(4,1fr);margin-bottom:14px;overflow:hidden}
.stat{padding:16px;border-right:1px solid #eef0f3}
.stat:last-child{border-right:0}
.stat span{font-size:13px;color:#6b7280}
.stat b{display:block;font-size:23px;margin-top:4px}
.primary,.ghost{border-radius:13px;padding:13px 16px;font-weight:700;border:1px solid transparent;width:100%}
.primary{background:#111827;color:white}
.ghost{background:#fff;border-color:#d1d5db;color:#111827}
.small{width:auto;padding:9px 12px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:10px}
.fileLabel{text-align:center;display:block}
.quizhead,.row{display:flex;justify-content:space-between;align-items:center;gap:12px}
.pill{font-size:12px;background:#eef2f7;padding:7px 10px;border-radius:999px}
.statement{font-size:23px;line-height:1.7;margin:28px 0;word-break:keep-all}
.choices{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:12px}
.ox{font-size:38px;font-weight:800;padding:24px;border-radius:18px;border:2px solid #e5e7eb;background:white}
.ox.selected{border-color:#111827;background:#f3f4f6}
.ox.answer-correct,.ox.correct-answer{border-color:var(--correct-border);color:var(--correct);background:var(--correct-bg)}
.ox.answer-wrong{border-color:var(--wrong-border);color:var(--wrong);background:var(--wrong-bg)}
.result{margin-top:18px;line-height:1.6;border:1px solid #e5e7eb;border-radius:15px;padding:16px 18px}
.result .verdict{font-size:21px;font-weight:800}
.result.is-correct{background:var(--correct-bg);border-color:#bbf7d0}
.result.is-wrong{background:var(--wrong-bg);border-color:#fecaca}
.result.is-correct .verdict,.result.is-correct .streakLine{color:var(--correct)}
.result.is-wrong .verdict,.result.is-wrong .streakLine{color:var(--wrong)}
.sourceBox{margin:14px 0 16px;padding:12px 14px;border:1px solid #e5e7eb;border-radius:12px;background:#f9fafb;font-size:14px;line-height:1.65}
.sourceTitle{font-weight:800;margin-bottom:4px}
.multiSource{background:rgba(255,255,255,.72);margin-bottom:12px}
.multiSource ul{margin:6px 0 0;padding-left:20px}
.multiSource li{margin:3px 0}
.streakLine{display:block;margin-top:8px}
.hidden{display:none!important}
dialog{border:0;border-radius:20px;padding:0;max-width:620px;width:min(92vw,620px)}
dialog::backdrop{background:rgba(0,0,0,.48)}
.modal{padding:22px}
label{display:block;font-size:14px;font-weight:700;margin-top:12px}
input,textarea,select{width:100%;margin-top:6px;padding:12px;border:1px solid #d1d5db;border-radius:11px;background:white}
textarea{min-height:120px;resize:vertical}
@media (max-width:640px){
  .shell{padding:14px 12px 40px}
  h1{font-size:21px}
  .stats{grid-template-columns:1fr 1fr}
  .stat:nth-child(2){border-right:0}
  .stat:nth-child(-n+2){border-bottom:1px solid #eef0f3}
  .statement{font-size:20px}
}
@media (min-width:900px){
  .shell{max-width:760px;padding-top:15px}
  h1{font-size:21px}
  .card{padding:18px}
  .stat{padding:13px 14px}
  .stat b{font-size:20px}
  .statement{font-size:20px;line-height:1.62;margin:22px 0}
  .ox{font-size:34px;padding:19px}
  .primary,.ghost{padding:11px 14px}
}

#afterBtns{margin-top:10px}
#afterBtns #nextBtn{margin-bottom:10px}


/* multi-subject selector */
.subjectRow{align-items:center;gap:14px}
.subjectButtons{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}
.subjectBtn{border:1px solid #d1d5db;background:#fff;border-radius:999px;padding:8px 12px;font-weight:700;cursor:pointer}
.subjectBtn.active{background:#111827;color:#fff;border-color:#111827}
.primary:disabled{opacity:.5;cursor:not-allowed}
@media(max-width:640px){
  .subjectRow{align-items:flex-start;flex-direction:column}
  .subjectButtons{width:100%;justify-content:flex-start}
  .subjectBtn{flex:1}
}