:root {
  --bg: #f6f7fb;
  --surface: #ffffff;
  --border: #e2e5ec;
  --text: #16181f;
  --text-muted: #5b6070;
  --brand: #4c5bff;
  --brand-dark: #3843c9;
  --success: #1f9d55;
  --danger: #d64545;
  --radius: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #10121a;
    --surface: #181b26;
    --border: #2a2e3d;
    --text: #eef0f6;
    --text-muted: #9aa0b4;
  }
}

* {
  box-sizing: border-box;
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--brand);
  color: white;
  font-weight: 700;
}

.brand small {
  display: block;
  color: var(--text-muted);
  font-weight: 400;
}

.shell {
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 12px;
  color: var(--brand);
  font-weight: 700;
}

.hero__copy h1 {
  font-size: clamp(24px, 4vw, 34px);
  margin: 8px 0 12px;
}

.hero__copy p {
  color: var(--text-muted);
  max-width: 60ch;
}

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-top: 20px;
}

.panel__heading {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 16px;
}

.panel__meta {
  color: var(--text-muted);
  font-size: 13px;
}

.start-form {
  display: grid;
  gap: 14px;
}

.field {
  display: grid;
  gap: 6px;
}

.field input {
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
}

.checkbox-field {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 14px;
}

.form-error {
  color: var(--danger);
  font-size: 14px;
}

.hero__actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.button {
  border: none;
  border-radius: 8px;
  padding: 10px 18px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}

.button--primary {
  background: var(--brand);
  color: white;
}

.button--primary:hover {
  background: var(--brand-dark);
}

.button--secondary {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
}

.button--ghost {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
}

.button--danger {
  background: var(--danger);
  color: white;
}

.button--small {
  padding: 6px 12px;
  font-size: 13px;
}

.button--full {
  width: 100%;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 14px;
  margin-top: 24px;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  display: grid;
  gap: 6px;
}

.stat-card span {
  color: var(--text-muted);
  font-size: 13px;
}

.stat-card strong {
  font-size: 22px;
}

.stat-card small {
  color: var(--text-muted);
  font-size: 12px;
}

.meter {
  height: 6px;
  border-radius: 999px;
  background: var(--border);
  overflow: hidden;
}

.meter span {
  display: block;
  height: 100%;
  background: var(--brand);
}

.meter--large {
  height: 10px;
}

.coverage-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 10px;
}

.coverage-card {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  display: grid;
  gap: 4px;
}

.coverage-card strong {
  font-size: 14px;
}

.coverage-card span {
  color: var(--text-muted);
  font-size: 13px;
}

.exam-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 20px;
}

@media (max-width: 720px) {
  .exam-layout {
    grid-template-columns: 1fr;
  }
}

.exam-sidebar {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  align-self: start;
  display: grid;
  gap: 12px;
}

.exam-progress-copy {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.exam-progress-copy strong {
  font-size: 20px;
}

.question-navigator {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
}

.nav-dot {
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  border-radius: 6px;
  padding: 6px 0;
  font-size: 12px;
  cursor: pointer;
}

.nav-dot--answered {
  border-color: var(--brand);
  color: var(--brand);
}

.nav-dot--active {
  background: var(--brand);
  color: white;
  border-color: var(--brand);
}

.exam-main {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.question-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.category-pill {
  display: inline-block;
  background: rgba(76, 91, 255, 0.12);
  color: var(--brand);
  border-radius: 999px;
  padding: 4px 10px;
  font-size: 12px;
  font-weight: 700;
}

.question-card h1 {
  font-size: 20px;
  margin: 0 0 16px;
}

.answer-options {
  border: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 10px;
}

.answer-option {
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  cursor: pointer;
}

.answer-option:has(input:checked) {
  border-color: var(--brand);
  background: rgba(76, 91, 255, 0.08);
}

.answer-option__letter {
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 6px;
  background: var(--border);
  font-size: 12px;
  font-weight: 700;
}

.question-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 18px;
}

.results-hero {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.score-ring {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  border: 6px solid var(--brand);
  display: grid;
  place-items: center;
  font-size: 20px;
  font-weight: 700;
}

.results-actions {
  display: flex;
  gap: 10px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.category-results {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 10px;
}

.review-section {
  margin-top: 24px;
}

.answer-review {
  display: grid;
  gap: 14px;
}

.review-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--success);
  border-radius: 10px;
  padding: 16px;
}

.review-card--incorrect {
  border-left-color: var(--danger);
}

.review-card h3 {
  margin: 8px 0;
  font-size: 16px;
}

.review-card .explanation {
  color: var(--text-muted);
}

.review-card .source {
  font-size: 13px;
  color: var(--text-muted);
}

.review-card .source a {
  color: var(--brand);
}

.dialog {
  border: none;
  border-radius: var(--radius);
  padding: 24px;
  max-width: 420px;
  background: var(--surface);
  color: var(--text);
}

.dialog::backdrop {
  background: rgba(0, 0, 0, 0.4);
}

.dialog__actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 16px;
}