:root {
  --bg: #0f1419;
  --panel: #1a2028;
  --panel2: #242d38;
  --border: #2f3a48;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #4fb3ff;
  --accent-hover: #7cc4ff;
  --correct: #3fb950;
  --wrong: #f85149;
  --warn: #d29922;
}
* { 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);
  line-height: 1.55;
}
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 28px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}
.brand h1 { margin: 0; font-size: 20px; color: var(--accent); }
.subtitle { font-size: 12px; color: var(--muted); }
nav button {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px 16px;
  margin-left: 8px;
  cursor: pointer;
  border-radius: 6px;
  font-size: 14px;
  transition: all 0.15s;
}
nav button:hover { background: var(--panel2); border-color: var(--accent); }
nav button.active { background: var(--accent); color: var(--bg); font-weight: 600; border-color: var(--accent); }
main {
  max-width: 960px;
  margin: 0 auto;
  padding: 28px;
}
footer {
  text-align: center;
  padding: 20px;
  color: var(--muted);
  font-size: 12px;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

/* Home cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 20px;
}
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px;
  cursor: pointer;
  transition: transform 0.15s, border-color 0.15s;
}
.card:hover { transform: translateY(-2px); border-color: var(--accent); }
.card h3 { margin-top: 0; color: var(--accent); }
.card p { color: var(--muted); font-size: 14px; margin-bottom: 0; }

/* Learn */
.learn-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
}
.sidebar {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px;
  max-height: calc(100vh - 140px);
  overflow-y: auto;
  position: sticky;
  top: 80px;
}
.sidebar h4 { margin: 12px 0 6px; font-size: 13px; text-transform: uppercase; color: var(--muted); }
.sidebar a {
  display: block;
  padding: 8px 10px;
  color: var(--text);
  text-decoration: none;
  border-radius: 5px;
  font-size: 14px;
  border-left: 3px solid transparent;
}
.sidebar a:hover { background: var(--panel2); }
.sidebar a.active { background: var(--panel2); border-left-color: var(--accent); color: var(--accent); }
.content {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 24px;
  overflow-x: hidden;
}
.content h1 { color: var(--accent); border-bottom: 1px solid var(--border); padding-bottom: 10px; }
.content h2 { color: var(--accent-hover); margin-top: 32px; }
.content h3 { color: var(--text); }
.content code { background: var(--panel2); padding: 2px 6px; border-radius: 3px; font-size: 0.9em; }
.content pre { background: var(--panel2); padding: 14px; border-radius: 6px; overflow-x: auto; }
.content blockquote { border-left: 4px solid var(--accent); padding: 8px 16px; color: var(--muted); background: var(--panel2); margin: 16px 0; }
.table-wrap { overflow-x: auto; margin: 16px 0; }
.content table { border-collapse: collapse; margin: 0; min-width: 100%; }
.content th, .content td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; white-space: nowrap; }
.content th { background: var(--panel2); color: var(--accent); }
.content img { max-width: 100%; height: auto; border-radius: 6px; }
.content a { color: var(--accent); }
.btn-print { display: inline-block; margin-bottom: 16px; padding: 7px 16px; background: var(--panel2); border: 1px solid var(--border); border-radius: 6px; color: var(--accent); cursor: pointer; font-size: 0.9em; }
.btn-print:hover { background: var(--border); }
.name-input-row { margin: 12px 0 20px; }
.name-input-row label { color: var(--text); font-size: 0.95em; }
.name-input { margin-left: 8px; padding: 7px 12px; background: var(--panel2); border: 1px solid var(--border); border-radius: 6px; color: var(--text); font-size: 0.9em; width: 280px; }
.candidate-name { font-size: 1.1em; font-weight: 600; color: var(--accent); margin-bottom: 4px; }

/* Drill + Mock shared */
.session-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 20px;
  margin-bottom: 20px;
}
.session-header h2 { margin: 0; color: var(--accent); font-size: 18px; }
.stats { display: flex; gap: 16px; font-size: 14px; color: var(--muted); }
.stats strong { color: var(--text); }
#timer { font-variant-numeric: tabular-nums; font-weight: 600; color: var(--warn); font-size: 16px; }

.question-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px 28px;
  margin-bottom: 18px;
}
.question-card .qnum { color: var(--muted); font-size: 12px; margin-bottom: 6px; text-transform: uppercase; }
.question-card .stem { font-size: 16px; margin-bottom: 14px; line-height: 1.6; }
.options { list-style: none; padding: 0; margin: 0; }
.options li {
  padding: 11px 14px;
  margin-bottom: 8px;
  background: var(--panel2);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.12s;
  display: flex;
  align-items: flex-start;
  gap: 10px;
}
.options li:hover { border-color: var(--accent); }
.options li.selected { border-color: var(--accent); background: #1e2d3f; }
.options li.correct { border-color: var(--correct); background: #0d2818; }
.options li.wrong { border-color: var(--wrong); background: #2d1014; }
.options li .letter {
  font-weight: 600;
  color: var(--accent);
  min-width: 22px;
}
.options li.disabled { cursor: default; }

.feedback {
  margin-top: 14px;
  padding: 12px 16px;
  border-radius: 6px;
  font-size: 14px;
}
.feedback.correct { background: #0d2818; border: 1px solid var(--correct); color: #7ee787; }
.feedback.wrong { background: #2d1014; border: 1px solid var(--wrong); color: #ffa198; }

.actions { margin-top: 16px; display: flex; gap: 10px; }
button.primary {
  background: var(--accent);
  color: var(--bg);
  border: none;
  padding: 10px 22px;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
  font-size: 14px;
}
button.primary:hover { background: var(--accent-hover); }
button.primary:disabled { opacity: 0.5; cursor: not-allowed; }
button.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 22px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 14px;
}
button.secondary:hover { border-color: var(--accent); }

.results {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 32px;
  text-align: center;
}
.results .score {
  font-size: 56px;
  font-weight: 700;
  color: var(--accent);
  margin: 20px 0;
}
.results .verdict { font-size: 20px; color: var(--muted); }
.results .pass { color: var(--correct); }
.results .fail { color: var(--wrong); }
.results-table { margin-top: 30px; text-align: left; }
.results-table tbody tr.review-row { cursor: pointer; }
.results-table tbody tr.review-row:hover td { background: rgba(30, 45, 63, 0.6); }

/* Selectors */
.selector-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 20px;
}
.selector-grid .card h3 { font-size: 16px; }
.selector-grid .card .meta {
  font-size: 12px;
  color: var(--muted);
  margin-top: 8px;
  display: flex;
  justify-content: space-between;
}

/* Report error */
.report-error {
  margin-top: 12px;
  font-size: 12px;
  color: var(--muted);
  text-align: right;
}
.report-error a {
  color: var(--accent);
  text-decoration: none;
  margin: 0 2px;
}
.report-error a:hover { text-decoration: underline; }

/* Disclaimer */
.disclaimer {
  margin-top: 28px;
  padding: 18px 22px;
  background: var(--panel2);
  border: 1px solid var(--warn);
  border-radius: 8px;
  font-size: 13px;
  color: var(--muted);
  line-height: 1.6;
}
.disclaimer strong { color: var(--warn); }
.disclaimer a { color: var(--accent); text-decoration: none; }
.disclaimer a:hover { text-decoration: underline; }

/* Lessons */
.lesson-content {
  max-width: 780px;
}
.lesson-content h2 {
  margin-top: 2em;
  padding-top: 1em;
  border-top: 1px solid var(--border);
  color: var(--accent);
}
.lesson-content h3 {
  color: var(--text);
  margin-top: 1.4em;
}
.lesson-content blockquote {
  border-left: 3px solid var(--accent);
  margin: 12px 0;
  padding: 8px 16px;
  background: var(--panel2);
  border-radius: 0 6px 6px 0;
  color: var(--text);
}
.lesson-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 14px 0;
  font-size: 0.95em;
}
.lesson-content th {
  background: var(--panel2);
  padding: 8px 12px;
  text-align: left;
  border-bottom: 2px solid var(--border);
}
.lesson-content td {
  padding: 7px 12px;
  border-bottom: 1px solid var(--border);
}
.lesson-content tr:last-child td { border-bottom: none; }
.lesson-drill-cta {
  max-width: 780px;
  margin: 32px 0 40px;
  padding: 24px;
  background: var(--panel2);
  border: 1px solid var(--accent);
  border-radius: 10px;
  text-align: center;
}
.lesson-drill-cta p { margin: 0 0 14px; color: var(--muted); }
.btn-primary {
  background: var(--accent);
  color: #0f1419;
  border: none;
  border-radius: 6px;
  padding: 10px 24px;
  font-size: 1em;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-primary:hover { background: var(--accent-hover); }
.btn-back {
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 6px;
  padding: 6px 14px;
  font-size: 0.9em;
  cursor: pointer;
  margin-bottom: 18px;
  display: inline-block;
}
.btn-back:hover { border-color: var(--accent); color: var(--accent); }

@media (max-width: 768px) {
  .learn-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; max-height: none; }
  header { flex-direction: column; gap: 10px; padding: 14px; }
  nav button { margin-left: 0; margin-right: 6px; }
  main { padding: 16px; }
}

@media print {
  header, nav, .sidebar, .btn-back, .btn-print, .lesson-drill-cta, .actions, .name-input-row { display: none !important; }
  body { background: #fff; color: #000; }
  main { padding: 0; }
  .learn-layout { display: block; }
  .content { border: none; border-radius: 0; padding: 0; box-shadow: none; }
  .content h1, .content h2 { color: #000; }
  .content th { background: #eee; color: #000; }
  .content td, .content th { border-color: #999; }
  a { color: inherit; text-decoration: none; }
}