:root {
  --bg: #0f172a;
  --bg-soft: #111827;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --ok: #15803d;
  --ok-bg: #ecfdf3;
  --bad: #b91c1c;
  --bad-bg: #fef2f2;
  --line: #e2e8f0;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  color: var(--text);
  font-family: Inter, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: linear-gradient(180deg, #0f172a 0%, #0b1220 100%);
  background-attachment: fixed;
}
.container { max-width: 960px; margin: 0 auto; padding: 24px; }
.hero { color: #fff; margin-bottom: 16px; }
.hero h1 { margin: 0 0 8px; }
.hero p { margin: 0; color: #cbd5e1; }
.card {
  background: var(--card);
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 14px 34px rgba(2, 6, 23, .35);
}
.field-group { margin: 0 0 18px; }
.field-title { margin: 0 0 8px; font-weight: 700; }
.stack label { display: block; margin: 10px 0; }
.segmented { display: flex; gap: 8px; }
.seg { border: 1px solid var(--line); border-radius: 10px; padding: 8px 12px; cursor: pointer; }
select { width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; font-size: 15px; }
label { display: block; }
.hint { color: var(--muted); margin: 8px 0 0; }
.muted { color: var(--muted); margin: 0; }
.answers { margin: 14px 0; display: grid; gap: 10px; }
.answer { border: 1px solid var(--line); padding: 12px; border-radius: 12px; transition: .2s; }
.answer:hover { border-color: #93c5fd; background: #f8fbff; }
.answer.correct { border-color: var(--ok); background: var(--ok-bg); }
.answer.wrong { border-color: var(--bad); background: var(--bad-bg); }
.actions { margin-top: 12px; }
button { border: 0; border-radius: 12px; padding: 11px 16px; cursor: pointer; font-weight: 600; }
button.primary { background: var(--primary); color: #fff; }
button.primary:hover { background: var(--primary-hover); }
.progress-row { display: flex; justify-content: space-between; margin-bottom: 8px; }
.progress { width: 100%; height: 8px; border-radius: 999px; background: #e2e8f0; overflow: hidden; margin-bottom: 14px; }
.progress span { display: block; height: 100%; background: linear-gradient(90deg, #60a5fa, #2563eb); }
.question-image-wrap { margin: 14px 0 18px; display: grid; gap: 10px; }
.question-image { max-width: 100%; height: auto; border: 1px solid var(--line); border-radius: 12px; }
.result-summary { border: 1px solid var(--line); border-radius: 12px; padding: 14px; margin: 10px 0 16px; }
.result-summary.pass { border-color: var(--ok); background: var(--ok-bg); }
.result-summary.fail-block { border-color: var(--bad); background: var(--bad-bg); }
.errors { display: grid; gap: 10px; padding-left: 18px; }
.ok { color: var(--ok); font-weight: 700; }
.hidden { display: none; }
.disabled { opacity: .5; }


.modal {
  position: fixed;
  inset: 0;
  background: rgba(2, 6, 23, 0.68);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
}
.modal-card {
  width: min(760px, 100%);
  background: #fff;
  border-radius: 14px;
  padding: 18px;
  box-shadow: 0 18px 38px rgba(0,0,0,.35);
}
.modal-card h2 { margin-top: 0; }
.modal-card p { margin: 10px 0; line-height: 1.45; }

.modal.hidden { display: none; }

.modal-card {
  border: 2px solid #ef4444;
  background: linear-gradient(180deg, #fff5f5 0%, #ffe4e6 100%);
}
.modal-card h2 { color: #b91c1c; }
button.danger { background: #dc2626; color: #fff; }
button.danger:hover { background: #b91c1c; }