:root {
  --bg: #0f1226;
  --bg-soft: #171a36;
  --card: #1e2244;
  --card-2: #252a52;
  --text: #e8eaf6;
  --muted: #9aa0c7;
  --accent: #6c8cff;
  --accent-2: #8a6cff;
  --ok: #2ecc71;
  --ok-bg: rgba(46, 204, 113, .12);
  --bad: #ff5d6c;
  --bad-bg: rgba(255, 93, 108, .12);
  --radius: 16px;
  --shadow: 0 10px 30px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background:
    radial-gradient(1200px 600px at 10% -10%, #2a2f63 0%, transparent 55%),
    radial-gradient(1000px 500px at 110% 10%, #3a2a63 0%, transparent 50%),
    var(--bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Шапка */
.topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 22px;
  position: sticky;
  top: 0;
  backdrop-filter: blur(8px);
  background: linear-gradient(180deg, rgba(15, 18, 38, .9), rgba(15, 18, 38, .55));
  border-bottom: 1px solid rgba(255, 255, 255, .06);
  z-index: 5;
}
.topbar h1 { font-size: 1.05rem; margin: 0; font-weight: 700; letter-spacing: .2px; }
.topbar-spacer { flex: 1; }
.home-btn {
  background: var(--card-2); color: var(--text);
  border: 1px solid rgba(255, 255, 255, .08);
  padding: 8px 14px; border-radius: 10px; cursor: pointer; font-size: .9rem;
}
.home-btn:hover { background: var(--card); }

main {
  flex: 1;
  width: 100%;
  max-width: 820px;
  margin: 0 auto;
  padding: 26px 18px 48px;
}

.lead { color: var(--muted); line-height: 1.5; margin: 0 0 22px; }
.error { color: var(--bad); }

/* Карточки предметов */
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 14px;
}
.subject-card {
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  padding: 22px 14px;
  background: linear-gradient(160deg, var(--card), var(--card-2));
  border: 1px solid rgba(255, 255, 255, .07);
  border-radius: var(--radius);
  color: var(--text);
  cursor: pointer;
  transition: transform .12s ease, border-color .12s ease, box-shadow .12s ease;
  text-align: center;
}
.subject-card:hover:not(:disabled) {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow);
}
.subject-card.is-soon { opacity: .5; cursor: not-allowed; }
.subject-icon { font-size: 2.1rem; }
.subject-name { font-weight: 600; font-size: .98rem; }
.subject-progress { font-size: .78rem; color: var(--ok); }
.subject-soon { font-size: .75rem; color: var(--muted); text-transform: uppercase; letter-spacing: .5px; }

/* Прогресс / шапка квиза */
.quiz-head { margin-bottom: 18px; }
.quiz-meta { display: flex; align-items: center; justify-content: space-between; margin-bottom: 10px; gap: 12px; }
.topic-chip {
  background: rgba(108, 140, 255, .15);
  color: #c5d0ff;
  border: 1px solid rgba(108, 140, 255, .3);
  padding: 5px 12px; border-radius: 999px; font-size: .82rem; font-weight: 600;
}
.counter { color: var(--muted); font-size: .9rem; font-variant-numeric: tabular-nums; }
.progress { height: 9px; background: rgba(255, 255, 255, .07); border-radius: 999px; overflow: hidden; }
.progress-fill {
  height: 100%; width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 999px; transition: width .35s ease;
}

/* Карточка вопроса */
.card {
  background: linear-gradient(160deg, var(--card), var(--bg-soft));
  border: 1px solid rgba(255, 255, 255, .07);
  border-radius: var(--radius);
  padding: 24px 22px;
  box-shadow: var(--shadow);
}
.question-text { font-size: 1.18rem; line-height: 1.5; font-weight: 600; margin-bottom: 20px; }

.options { display: flex; flex-direction: column; gap: 10px; }
.option {
  text-align: left;
  padding: 14px 16px;
  background: var(--card-2);
  border: 1.5px solid rgba(255, 255, 255, .08);
  border-radius: 12px;
  color: var(--text);
  font-size: 1rem; line-height: 1.4;
  cursor: pointer;
  transition: border-color .12s, background .12s, transform .08s;
}
.option:hover:not(.disabled) { border-color: var(--accent); transform: translateX(2px); }
.option.disabled { cursor: default; }
.option.correct { border-color: var(--ok); background: var(--ok-bg); }
.option.wrong { border-color: var(--bad); background: var(--bad-bg); }

/* Обратная связь */
.feedback {
  margin-top: 18px; padding: 12px 14px; border-radius: 12px; font-weight: 600; font-size: .96rem;
}
.feedback.ok { background: var(--ok-bg); color: #b6f5d0; border: 1px solid rgba(46, 204, 113, .4); }
.feedback.bad { background: var(--bad-bg); color: #ffc2c8; border: 1px solid rgba(255, 93, 108, .4); }

/* Пояснение */
.hint {
  margin-top: 18px;
  background: rgba(255, 255, 255, .03);
  border: 1px solid rgba(255, 255, 255, .08);
  border-radius: 12px;
  padding: 4px 16px;
}
.hint summary {
  cursor: pointer; padding: 12px 0; font-weight: 600; color: #ffd479; list-style: none;
}
.hint summary::-webkit-details-marker { display: none; }
.hint[open] summary { border-bottom: 1px solid rgba(255, 255, 255, .08); }
.hint-body { padding: 14px 0 6px; line-height: 1.6; color: #dfe2f7; }
.hint-note { font-size: .82rem; color: var(--muted); margin: 0 0 12px; font-style: italic; }

/* Кнопки */
.actions { display: flex; gap: 12px; margin-top: 20px; }
.actions.center { justify-content: center; }
.btn {
  padding: 12px 22px; border-radius: 12px; border: none; cursor: pointer;
  font-size: 1rem; font-weight: 600; transition: transform .08s, filter .12s;
}
.btn:hover { filter: brightness(1.08); transform: translateY(-1px); }
.btn-primary { background: linear-gradient(90deg, var(--accent), var(--accent-2)); color: #fff; }
.btn-secondary { background: var(--card-2); color: var(--text); border: 1px solid rgba(255, 255, 255, .1); }

/* Экран завершения */
.done-card { text-align: center; }
.done-emoji { font-size: 3.5rem; }
.done-card h2 { margin: 10px 0; }
.done-card p { color: var(--muted); line-height: 1.6; }

/* Подвал */
.foot {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 22px; color: var(--muted); font-size: .82rem;
  border-top: 1px solid rgba(255, 255, 255, .06);
}
.link-btn { background: none; border: none; color: var(--muted); cursor: pointer; text-decoration: underline; font-size: .82rem; }
.link-btn:hover { color: var(--bad); }

@media (max-width: 520px) {
  .question-text { font-size: 1.08rem; }
  .topbar h1 { font-size: .92rem; }
  main { padding: 18px 12px 40px; }
}