:root {
  --orange: #FF9900;
  --dark: #232F3E;
  --green: #1D8102;
  --red: #D13212;
  --bg: #F4F6F8;
  --card: #FFFFFF;
  --border: #E2E6EA;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--dark);
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

header h1 {
  margin: 0 0 4px;
  font-size: 1.6rem;
  color: var(--dark);
}

.subtitle {
  margin: 0 0 24px;
  color: #5a6472;
  font-size: 0.95rem;
}

/* ---------- Controls bar ---------- */
.controls-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  gap: 16px;
  margin-bottom: 22px;
  padding: 14px 16px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
}

.control {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 0.8rem;
  color: #5a6472;
}

.control input, .control select {
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.9rem;
  min-width: 160px;
  font-family: inherit;
}

.control input:focus, .control select:focus {
  outline: none;
  border-color: var(--orange);
}

.controls-bar .link-btn {
  margin-left: auto;
  margin-bottom: 4px;
}

/* ---------- Topic grid ---------- */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 14px;
}

.topic-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
  cursor: pointer;
  transition: border-color 0.15s, transform 0.1s, box-shadow 0.15s;
  text-align: left;
}

.topic-card:hover {
  border-color: var(--orange);
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(0,0,0,0.06);
}

.topic-card .topic-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--orange);
  background: #FFF3E0;
  padding: 3px 8px;
  border-radius: 10px;
  margin-bottom: 10px;
}

.topic-card h3 {
  margin: 0 0 6px;
  font-size: 1.05rem;
  color: var(--dark);
}

.topic-card p {
  margin: 0;
  font-size: 0.85rem;
  color: #5a6472;
  line-height: 1.4;
}

.topic-card .q-count {
  margin-top: 12px;
  font-size: 0.78rem;
  color: #8a929c;
}

.topic-card .best-score {
  margin-top: 6px;
  font-size: 0.78rem;
  color: var(--green);
  font-weight: 600;
}

/* ---------- Leaderboard & History ---------- */
.leaderboard {
  margin: 24px 0;
}

.leaderboard h3 {
  margin: 0 0 10px;
  font-size: 1rem;
}

.leaderboard-row, .history-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 8px;
  font-size: 0.88rem;
}

.leaderboard-row .rank {
  display: inline-block;
  width: 22px;
  font-weight: 700;
  color: var(--orange);
}

.leaderboard-row .name, .history-row .name {
  font-weight: 600;
  flex: 1;
  margin-left: 8px;
}

.leaderboard-row .pct, .history-row .pct {
  font-weight: 700;
  color: var(--dark);
}

.history-row .meta {
  color: #8a929c;
  font-size: 0.8rem;
  margin-right: 12px;
}

.empty-state {
  color: #8a929c;
  font-size: 0.9rem;
  padding: 16px;
  text-align: center;
}

/* ---------- Exam header ---------- */
.exam-header {
  position: relative;
}

.link-btn {
  background: none;
  border: none;
  color: var(--orange);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  padding: 0;
  margin-bottom: 10px;
  display: inline-block;
}
.link-btn:hover { text-decoration: underline; }

/* ---------- Progress ---------- */
.progress-bar-wrap {
  position: sticky;
  top: 0;
  height: 6px;
  background: var(--border);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 20px;
  z-index: 10;
}
.progress-bar {
  height: 100%;
  width: 0%;
  background: var(--orange);
  transition: width 0.2s ease;
}

/* ---------- Question cards ---------- */
.question-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
  margin-bottom: 14px;
}

.question-title {
  font-weight: 600;
  margin: 0 0 12px;
  line-height: 1.4;
}

.question-number {
  color: var(--orange);
  margin-right: 6px;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.option {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.option:hover {
  border-color: var(--orange);
}

.option input {
  accent-color: var(--orange);
}

.option.selected {
  border-color: var(--orange);
  background: #FFF6E8;
}

/* Result states */
.option.correct-answer {
  border-color: var(--green);
  background: #EBF7E8;
}
.option.wrong-answer {
  border-color: var(--red);
  background: #FCEAE7;
}

.badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 12px;
  margin-left: 8px;
  vertical-align: middle;
}
.badge.correct { background: #EBF7E8; color: var(--green); }
.badge.incorrect { background: #FCEAE7; color: var(--red); }

.explanation {
  margin-top: 10px;
  padding: 10px 12px;
  background: #F0F3F6;
  border-radius: 8px;
  font-size: 0.88rem;
  color: #3d4750;
}

/* ---------- Submit bar ---------- */
.submit-bar {
  position: sticky;
  bottom: 0;
  background: var(--bg);
  padding: 14px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border);
}

.answered-count {
  color: #5a6472;
  font-size: 0.9rem;
}

#submit-btn {
  background: var(--orange);
  color: var(--dark);
  border: none;
  font-weight: 700;
  padding: 12px 24px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.95rem;
}
#submit-btn:hover { background: #e88b00; }
#submit-btn:disabled {
  background: #ccc;
  cursor: not-allowed;
}

/* ---------- Results ---------- */
.results {
  margin-top: 8px;
}

.score-card {
  background: var(--dark);
  color: #fff;
  border-radius: 10px;
  padding: 24px;
  text-align: center;
  margin-bottom: 24px;
}
.score-card .score-number {
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--orange);
}
.score-card .score-label {
  font-size: 1rem;
  color: #cfd6dd;
  margin-top: 4px;
}

.results-actions {
  display: flex;
  gap: 10px;
  margin-top: 16px;
}

#retake-btn, #choose-another-btn {
  background: transparent;
  border: 1px solid var(--orange);
  color: var(--orange);
  padding: 10px 18px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
}
#retake-btn:hover, #choose-another-btn:hover { background: #FFF6E8; }