/* ── Design tokens ─────────────────────────────────────────────────────── */
:root {
  --color-bg:         #0d1117;
  --color-surface:    #161b22;
  --color-border:     #30363d;
  --color-text:       #e6edf3;
  --color-muted:      #8b949e;
  --color-accent:     #58a6ff;
  --color-accent-dim: #1f6feb;
  --color-code-bg:    #161b22;
  --color-dataset-bg: #0d1117;
  --color-hover:      #21262d;
  --color-correct:    #238636;
  --color-incorrect:  #da3633;

  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --max-width: 860px;
}

/* ── Reset ─────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }

html { font-size: 16px; }

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  line-height: 1.65;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.tracking-banner {
  border-bottom: 1px solid var(--color-border);
  background: color-mix(in srgb, var(--color-surface) 88%, #1f6feb 12%);
  padding: 0.9rem 1rem;
}

.tracking-banner-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.tracking-banner-heading {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.3rem;
}

.tracking-banner-subtext {
  font-size: 0.82rem;
  color: var(--color-muted);
  margin-bottom: 0.65rem;
}

.tracking-option {
  margin-bottom: 0.6rem;
}

.tracking-option label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--color-text);
}

.tracking-option label:has(input:disabled) {
  cursor: default;
  opacity: 0.55;
}

.tracking-option-title {
  font-weight: 600;
}

.tracking-option-desc {
  margin: 0.2rem 0 0 1.5rem;
  font-size: 0.82rem;
  color: var(--color-muted);
}

.tracking-coming-soon {
  font-style: normal;
  font-size: 0.78rem;
  color: var(--color-muted);
  font-weight: 400;
}

.tracking-banner-actions {
  margin-top: 0.75rem;
  display: inline-flex;
  gap: 0.45rem;
}

.tracking-banner-actions button,
.tracking-settings-actions button {
  border: 1px solid var(--color-accent-dim);
  background: var(--color-accent-dim);
  color: #fff;
  border-radius: 6px;
  padding: 0.35rem 0.7rem;
  cursor: pointer;
  font-size: 0.82rem;
}

.tracking-banner-actions button:hover,
.tracking-settings-actions button:hover {
  background: var(--color-accent);
}

.tracking-secondary {
  border-color: var(--color-border) !important;
  background: transparent !important;
  color: var(--color-text) !important;
}

.tracking-secondary:hover {
  background: var(--color-hover) !important;
}

a { color: var(--color-accent); }
a:hover { text-decoration: underline; }

/* ── Site header ───────────────────────────────────────────────────────── */
.site-header {
  border-bottom: 1px solid var(--color-border);
  padding: 0.75rem 1.5rem;
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: baseline;
  gap: 1rem;
}
.site-logo {
  font-weight: 700;
  font-size: 1.05rem;
  text-decoration: none;
  color: var(--color-text);
}
.nav-tagline {
  font-size: 0.85rem;
  color: var(--color-muted);
}

/* ── Main content ──────────────────────────────────────────────────────── */
.main-content {
  flex: 1;
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* ── Site footer ───────────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 1rem 1.5rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-muted);
}

.site-credit {
  margin-top: 0.45rem;
  font-size: 0.72rem;
}

.tracking-settings-btn {
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text);
  border-radius: 6px;
  padding: 0.3rem 0.65rem;
  font-size: 0.78rem;
  cursor: pointer;
  margin-bottom: 0.65rem;
}

.tracking-settings-btn:hover {
  background: var(--color-hover);
}

.tracking-settings {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.54);
  display: grid;
  place-items: center;
  z-index: 25;
  padding: 1rem;
}

.tracking-settings-inner {
  width: min(640px, 100%);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
  padding: 1rem 1.15rem;
}

.tracking-settings-inner h2 {
  font-size: 1rem;
  margin-bottom: 0.45rem;
}

.tracking-settings-inner > p {
  color: var(--color-muted);
  font-size: 0.88rem;
  margin-bottom: 0.85rem;
}

.tracking-settings-actions {
  margin-top: 0.85rem;
  display: flex;
  gap: 0.5rem;
}

/* ── Quiz listing ──────────────────────────────────────────────────────── */
.quiz-listing h1 {
  font-size: 1.75rem;
  margin-bottom: 0.5rem;
}
.listing-intro {
  color: var(--color-muted);
  margin-bottom: 2rem;
}
.listing-actions {
  margin-bottom: 1.25rem;
}
.btn-start-quiz {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 1rem;
  border-radius: 6px;
  text-decoration: none;
  color: #fff;
  border: 1px solid color-mix(in srgb, var(--color-accent-dim) 80%, #ffffff 20%);
  background: linear-gradient(135deg, var(--color-accent-dim), #2f81f7);
}
.btn-start-quiz:hover {
  text-decoration: none;
  filter: brightness(1.08);
}
.question-grid {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}
.question-card a {
  display: block;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.25rem;
  text-decoration: none;
  color: var(--color-text);
  transition: border-color 0.15s, background 0.15s;
}
.question-card a:hover {
  border-color: var(--color-accent-dim);
  background: var(--color-hover);
}
.question-card h2 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
}
.snippet-count {
  font-size: 0.8rem;
  color: var(--color-muted);
}

/* ── Question page ─────────────────────────────────────────────────────── */
.question-page { max-width: 100%; }

.quiz-progress {
  margin: 0 0 1.25rem;
  padding: 0.8rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: color-mix(in srgb, var(--color-surface) 80%, var(--color-bg) 20%);
}

.quiz-progress-copy {
  font-size: 0.92rem;
  color: var(--color-text);
}

.quiz-controls-row {
  margin-top: 0.65rem;
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
}

.btn-restart {
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text);
  border-radius: 6px;
  padding: 0.3rem 0.7rem;
  font-size: 0.84rem;
  cursor: pointer;
}

.btn-restart:hover {
  background: var(--color-hover);
}

.quiz-progress-sep {
  margin: 0 0.45rem;
  color: var(--color-muted);
}

.quiz-progress-muted {
  margin-left: 0.25rem;
  color: var(--color-muted);
}

.question-header h1 {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.75rem;
}

/* Snippet tabs */
.snippets-section { margin-bottom: 1.5rem; }

.snippet-toolbar {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 0.5rem;
}

.diff-toggle {
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text);
  border-radius: 999px;
  padding: 0.3rem 0.75rem;
  font-size: 0.78rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.diff-toggle:hover {
  background: var(--color-hover);
}

.diff-toggle[aria-pressed='true'] {
  border-color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 18%, var(--color-surface));
}

.snippet-panels {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

.snippet-tabs {
  display: flex;
  gap: 0.25rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 0;
}
.snippet-tab {
  background: none;
  border: 1px solid transparent;
  border-bottom: none;
  padding: 0.5rem 1rem;
  cursor: pointer;
  color: var(--color-muted);
  font-size: 0.9rem;
  border-radius: 4px 4px 0 0;
  position: relative;
  bottom: -1px;
  transition: color 0.1s;
}
.snippet-tab.active {
  color: var(--color-text);
  border-color: var(--color-border);
  border-bottom-color: var(--color-bg);
  background: var(--color-bg);
}
.snippet-tab:hover:not(.active) { color: var(--color-text); }

.snippet-panel { display: none; padding: 0.75rem 0; }
.snippet-panel.active { display: block; }

.snippet-panel-title {
  display: none;
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 0.35rem;
  font-weight: 600;
}

.snippet-description {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-bottom: 0.5rem;
}

.snippets-section.grid-mode .snippet-panels {
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 0.65rem;
}

.snippets-section.grid-mode .snippet-panel {
  display: block;
  padding: 0.45rem;
  margin: 0;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-surface);
}

.snippets-section.grid-mode .snippet-panel-title {
  display: block;
}

.snippets-section.grid-mode .snippet-description {
  font-size: 0.78rem;
  line-height: 1.35;
  margin-bottom: 0.2rem;
}

.snippets-section.diff-on .snippet-viewer .line .diff-inline {
  background: color-mix(in srgb, var(--color-accent) 26%, transparent);
  outline: none;
  border-radius: 0;
}

.snippets-section.diff-on .snippet-viewer .line .diff-inline:first-child {
  border-top-left-radius: 3px;
  border-bottom-left-radius: 3px;
}

.snippets-section.diff-on .snippet-viewer .line .diff-inline:last-child {
  border-top-right-radius: 3px;
  border-bottom-right-radius: 3px;
}

@media (max-width: 1080px) {
  .snippets-section.grid-mode .snippet-panels {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  }
}

@media (max-width: 760px) {
  .snippets-section.grid-mode .snippet-panels {
    grid-template-columns: 1fr;
  }
}

/* Question prompt */
.question-prompt {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.25rem;
  font-size: 0.95rem;
}

/* Choices */
.choices-form fieldset { border: none; }
.btn-submit {
  margin-top: 0.75rem;
  padding: 0.55rem 1.5rem;
  background: var(--color-accent-dim);
  color: #fff;
  border: none;
  border-radius: 6px;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-submit:hover { background: var(--color-accent); }
.btn-submit:disabled { opacity: 0.5; cursor: default; }

/* Answer reveal */
.answer-reveal { margin-top: 2rem; }

.verdict {
  font-size: 1.1rem;
  font-weight: 700;
  padding: 0.6rem 1rem;
  border-radius: 6px;
  margin-bottom: 1rem;
}
.verdict.correct  { background: var(--color-correct);   color: #fff; }
.verdict.incorrect { background: var(--color-incorrect); color: #fff; }

.answer-text {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.25rem;
  font-size: 0.95rem;
  line-height: 1.7;
}

.quiz-navigation {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.btn-nav {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  padding: 0.5rem 0.95rem;
  text-decoration: none;
  border: 1px solid var(--color-accent-dim);
  background: var(--color-accent-dim);
  color: #fff;
}

.btn-nav:hover {
  text-decoration: none;
  background: var(--color-accent);
}

.btn-nav-secondary {
  border-color: var(--color-border);
  background: transparent;
  color: var(--color-text);
}

.btn-nav-secondary:hover {
  background: var(--color-hover);
}

.is-disabled {
  opacity: 0.5;
  pointer-events: none;
}

.is-hidden {
  display: none;
}

.quiz-final {
  margin-top: 0.9rem;
  color: var(--color-muted);
  font-size: 0.9rem;
}

.quiz-summary {
  margin-top: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 0.85rem 1rem;
  background: color-mix(in srgb, var(--color-surface) 84%, var(--color-bg) 16%);
}

.quiz-summary h3 {
  font-size: 0.98rem;
  margin-bottom: 0.5rem;
}

.quiz-summary ul {
  list-style: none;
  display: grid;
  gap: 0.35rem;
}

.quiz-summary li {
  font-size: 0.88rem;
  color: var(--color-text);
}

/* Benchmark results table */
.benchmark-results { margin-bottom: 1.5rem; }
.benchmark-results h3 { margin-bottom: 0.25rem; font-size: 1rem; }
.benchmark-meta {
  font-size: 0.8rem;
  color: var(--color-muted);
  margin-bottom: 0.75rem;
  font-family: monospace;
}
.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
.results-table th,
.results-table td {
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--color-border);
}
.results-table th { color: var(--color-muted); font-weight: 600; }

/* ── Preview page ──────────────────────────────────────────────────────── */
.preview-page header { margin-bottom: 1.5rem; }
.preview-badge {
  display: inline-block;
  background: #5a3e00;
  color: #e3b341;
  border-radius: 4px;
  padding: 0.2rem 0.6rem;
  font-size: 0.8rem;
  margin-top: 0.5rem;
}
.preview-section {
  margin-bottom: 2rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.25rem;
}
.preview-section h2 { font-size: 1.1rem; margin-bottom: 1rem; }
.preview-snippet { margin-bottom: 1.5rem; }
.preview-snippet h3 {
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
  font-family: monospace;
  color: var(--color-accent);
}
.result-json {
  background: var(--color-code-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 1rem;
  font-size: 0.8rem;
  overflow-x: auto;
  white-space: pre;
}

/* ── Utilities ─────────────────────────────────────────────────────────── */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}