:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --card: rgba(255,255,255,.82);
  --card-strong: #ffffff;
  --text: #172033;
  --muted: #667085;
  --line: rgba(23,32,51,.12);
  --brand: #dd2c4a;
  --brand-2: #ff8a00;
  --ok: #0f9f6e;
  --bad: #dd3444;
  --shadow: 0 20px 60px rgba(25, 37, 67, .12);
}
:root.dark {
  color-scheme: dark;
  --bg: #0f1220;
  --card: rgba(21,25,43,.78);
  --card-strong: #171b2d;
  --text: #f4f7fb;
  --muted: #a3adc2;
  --line: rgba(244,247,251,.12);
  --brand: #ff4d6d;
  --brand-2: #ffb703;
  --ok: #35d49b;
  --bad: #ff6070;
  --shadow: 0 24px 80px rgba(0, 0, 0, .35);
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 8% 12%, rgba(221,44,74,.18), transparent 28rem),
    radial-gradient(circle at 85% 8%, rgba(255,138,0,.18), transparent 26rem),
    var(--bg);
}
.bg-grid {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 42px 42px;
  mask-image: linear-gradient(to bottom, rgba(0,0,0,.35), transparent 75%);
}
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 18px min(5vw, 56px);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 14px; }
.logo {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  border-radius: 18px;
  color: #fff;
  font-weight: 900;
  font-size: 28px;
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  box-shadow: var(--shadow);
}
h1, h2, h3, p { margin: 0; }
h1 { font-size: clamp(20px, 3vw, 30px); }
.brand p, .muted { color: var(--muted); }
.layout {
  width: min(1180px, calc(100% - 28px));
  margin: 24px auto 56px;
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 20px;
}
.card {
  position: relative;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: var(--card);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}
.hero {
  grid-column: 1 / -1;
  padding: 28px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  overflow: hidden;
}
.hero h2 { margin: 8px 0 10px; font-size: clamp(26px, 4vw, 48px); letter-spacing: -.04em; }
.eyebrow {
  color: var(--brand);
  text-transform: uppercase;
  letter-spacing: .16em;
  font-size: 12px;
  font-weight: 800;
}
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; min-width: 360px; }
.stats div {
  padding: 18px;
  border-radius: 22px;
  background: var(--card-strong);
  border: 1px solid var(--line);
}
.stats strong { display: block; font-size: 32px; }
.stats span { color: var(--muted); font-size: 13px; }
.panel { padding: 22px; align-self: start; }
.field { display: grid; gap: 8px; margin-top: 18px; color: var(--muted); font-weight: 700; }
select {
  width: 100%;
  padding: 13px 14px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: var(--card-strong);
  color: var(--text);
  font: inherit;
}
.switch { display: flex; align-items: center; gap: 10px; margin: 18px 0; color: var(--muted); }
.switch input { width: 18px; height: 18px; accent-color: var(--brand); }
.actions { display: grid; gap: 10px; }
button {
  border: 0;
  border-radius: 16px;
  padding: 12px 16px;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
  transition: transform .18s ease, opacity .18s ease, border-color .18s ease;
}
button:hover { transform: translateY(-1px); }
button:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.primary { color: #fff; background: linear-gradient(135deg, var(--brand), var(--brand-2)); }
.ghost { color: var(--text); background: transparent; border: 1px solid var(--line); }
.danger { color: #fff; background: linear-gradient(135deg, #d92d20, #f97066); }
.mini { display: flex; justify-content: space-between; gap: 10px; margin-top: 18px; color: var(--muted); font-size: 14px; }
.quiz { padding: 24px; min-height: 460px; }
.quiz-head { display: flex; justify-content: space-between; gap: 16px; align-items: start; }
#questionTitle { margin-top: 8px; line-height: 1.5; font-size: clamp(20px, 2.4vw, 30px); }
.badge {
  display: inline-flex;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--brand);
  font-weight: 900;
  white-space: nowrap;
}
.options { display: grid; gap: 12px; margin: 24px 0; }
.option {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 12px;
  align-items: center;
  padding: 14px;
  border-radius: 18px;
  border: 1px solid var(--line);
  background: var(--card-strong);
  cursor: pointer;
  user-select: none;
}
.option .key {
  display: grid;
  place-items: center;
  height: 44px;
  border-radius: 14px;
  background: rgba(221,44,74,.10);
  color: var(--brand);
  font-weight: 900;
}
.option input { display: none; }
.option.selected { border-color: rgba(221,44,74,.58); box-shadow: inset 0 0 0 1px rgba(221,44,74,.28); }
.option.correct { border-color: rgba(15,159,110,.65); background: rgba(15,159,110,.10); }
.option.wrong { border-color: rgba(221,52,68,.65); background: rgba(221,52,68,.10); }
.feedback {
  padding: 16px;
  border-radius: 18px;
  line-height: 1.7;
  border: 1px solid var(--line);
  background: var(--card-strong);
}
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--bad); }
.quiz-actions { display: flex; flex-wrap: wrap; gap: 10px; justify-content: flex-end; }
.review { grid-column: 2; padding: 22px; }
.review-title { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
.result-box { margin-top: 14px; padding: 16px; border-radius: 18px; background: var(--card-strong); border: 1px solid var(--line); line-height: 1.8; }
.answer-sheet { margin-top: 14px; display: grid; gap: 10px; }
.answer-row {
  display: grid;
  grid-template-columns: 60px 1fr auto;
  gap: 12px;
  align-items: center;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--card-strong);
}
.answer-row strong { color: var(--brand); }
.hidden { display: none !important; }
@media (max-width: 880px) {
  .layout { grid-template-columns: 1fr; }
  .hero, .review { grid-column: auto; }
  .hero, .topbar { flex-direction: column; align-items: stretch; }
  .stats { min-width: 0; grid-template-columns: 1fr; }
}

.answer-group-title { margin: 18px 0 10px; font-size: 16px; }