:root {
  --bg: #0f1115;
  --bg-panel: #171a21;
  --bg-card: #1e222b;
  --border: #2b303b;
  --text: #e8e9ec;
  --text-dim: #9aa1ae;
  --accent: #d97757;
  --accent-dim: #8a5340;
  --good: #4caf7d;
  --bad: #e05c5c;
  --radius: 10px;
  font-size: 16px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-panel);
  position: sticky;
  top: 0;
  z-index: 10;
}

header h1 {
  font-size: 17px;
  margin: 0;
  font-weight: 600;
  letter-spacing: 0.2px;
}

header h1 span { color: var(--accent); }

nav {
  display: flex;
  gap: 4px;
}

nav button {
  background: transparent;
  border: none;
  color: var(--text-dim);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
}

nav button:hover { background: var(--bg-card); color: var(--text); }
nav button.active { background: var(--accent); color: #1a1a1a; }

main {
  max-width: 920px;
  margin: 0 auto;
  padding: 28px 24px 80px;
}

.view { display: none; }
.view.active { display: block; }

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
  margin-bottom: 16px;
}

.card h2 { margin-top: 0; }

.domain-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 18px 0;
}

@media (max-width: 640px) {
  .domain-grid { grid-template-columns: 1fr; }
}

.domain-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  cursor: pointer;
  transition: border-color 0.15s;
}
.domain-card:hover { border-color: var(--accent-dim); }

.domain-card .weight {
  float: right;
  color: var(--accent);
  font-weight: 700;
  font-size: 14px;
}

.domain-card h3 { margin: 0 0 6px; font-size: 15px; }
.domain-card p { margin: 0; color: var(--text-dim); font-size: 13.5px; }

.weight-bar-track {
  background: var(--bg);
  border-radius: 4px;
  height: 6px;
  margin-top: 10px;
  overflow: hidden;
}
.weight-bar-fill { height: 100%; background: var(--accent); }

.scenario-item {
  border-left: 3px solid var(--accent-dim);
  padding: 4px 0 4px 14px;
  margin-bottom: 14px;
}
.scenario-item h4 { margin: 0 0 4px; font-size: 14.5px; }
.scenario-item p { margin: 2px 0; color: var(--text-dim); font-size: 13.5px; }
.scenario-item .tags { color: var(--accent); font-size: 12.5px; margin-top: 4px; }

.pill {
  display: inline-block;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px 10px;
  font-size: 12px;
  color: var(--text-dim);
  margin: 2px 4px 2px 0;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
@media (max-width: 640px) { .two-col { grid-template-columns: 1fr; } }
.two-col ul { padding-left: 18px; margin: 8px 0; }
.two-col li { margin-bottom: 6px; font-size: 13.5px; color: var(--text-dim); }

.study-tabs {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 18px;
}
.study-tabs button {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 7px 13px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
}
.study-tabs button.active {
  background: var(--accent);
  color: #1a1a1a;
  border-color: var(--accent);
}

.markdown h1 { font-size: 22px; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.markdown h2 { font-size: 18px; margin-top: 28px; color: var(--accent); }
.markdown h3 { font-size: 15px; margin-top: 20px; color: var(--text); }
.markdown p { font-size: 14.5px; color: #d3d5da; }
.markdown blockquote {
  border-left: 3px solid var(--accent);
  margin: 14px 0;
  padding: 4px 16px;
  background: var(--bg-panel);
  border-radius: 0 8px 8px 0;
  font-size: 14px;
}
.markdown blockquote p { margin: 4px 0; }
.markdown table {
  border-collapse: collapse;
  width: 100%;
  margin: 14px 0;
  font-size: 13px;
}
.markdown th, .markdown td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}
.markdown th { background: var(--bg-panel); color: var(--accent); }
.markdown code {
  background: var(--bg-panel);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 13px;
  color: #f0b990;
}
.markdown pre {
  background: var(--bg-panel);
  padding: 12px 14px;
  border-radius: 8px;
  overflow-x: auto;
  font-size: 13px;
  border: 1px solid var(--border);
}
.markdown pre code { background: none; padding: 0; color: var(--text); }
.markdown hr { border: none; border-top: 1px solid var(--border); margin: 24px 0; }
.markdown ul, .markdown ol { font-size: 14.5px; color: #d3d5da; padding-left: 22px; }
.markdown li { margin-bottom: 4px; }
.markdown strong { color: #fff; }
.markdown li strong { color: var(--accent); }

.flash-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 10px;
}
.flash-controls select {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 13px;
}
.flash-progress { color: var(--text-dim); font-size: 13px; }

.flashcard {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  min-height: 220px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 32px 28px;
  cursor: pointer;
  font-size: 17px;
  user-select: none;
  transition: border-color 0.15s;
}
.flashcard:hover { border-color: var(--accent-dim); }
.flashcard .term { font-weight: 700; color: var(--accent); }
.flashcard .def { font-size: 14.5px; color: #d3d5da; text-align: left; line-height: 1.6; }
.flashcard .hint { display: block; margin-top: 14px; font-size: 12px; color: var(--text-dim); }

.flash-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-top: 18px;
}
.flash-actions button {
  border: none;
  border-radius: 8px;
  padding: 10px 20px;
  font-size: 14px;
  cursor: pointer;
  font-weight: 600;
}
.btn-review { background: var(--bg-card); border: 1px solid var(--border); color: var(--text); }
.btn-know { background: var(--good); color: #08260f; }

.quiz-setup { display: flex; gap: 12px; flex-wrap: wrap; align-items: end; margin-bottom: 18px; }
.quiz-setup label { display: block; font-size: 12.5px; color: var(--text-dim); margin-bottom: 4px; }
.quiz-setup select, .quiz-setup input {
  background: var(--bg-card); color: var(--text); border: 1px solid var(--border);
  border-radius: 8px; padding: 7px 10px; font-size: 13.5px;
}
.btn-primary {
  background: var(--accent); color: #1a1a1a; border: none; border-radius: 8px;
  padding: 9px 18px; font-size: 14px; font-weight: 700; cursor: pointer;
}
.btn-primary:hover { opacity: 0.92; }

.quiz-progress { color: var(--text-dim); font-size: 13px; margin-bottom: 10px; }
.quiz-scenario { color: var(--accent); font-size: 12.5px; margin-bottom: 6px; font-weight: 600; }
.quiz-stem { font-size: 15.5px; margin-bottom: 18px; }
.quiz-option {
  display: block;
  width: 100%;
  text-align: left;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 12px 14px;
  border-radius: 8px;
  margin-bottom: 8px;
  cursor: pointer;
  font-size: 14px;
}
.quiz-option:hover { border-color: var(--accent-dim); }
.quiz-option.correct { border-color: var(--good); background: #12241a; }
.quiz-option.incorrect { border-color: var(--bad); background: #271414; }
.quiz-option.disabled { cursor: default; pointer-events: none; }
.quiz-explain {
  margin-top: 14px;
  padding: 12px 14px;
  background: var(--bg-panel);
  border-radius: 8px;
  font-size: 13.5px;
  color: #d3d5da;
  border-left: 3px solid var(--accent);
}
.quiz-nav { display: flex; justify-content: flex-end; margin-top: 18px; }

.quiz-summary-score { font-size: 40px; font-weight: 800; color: var(--accent); }
.quiz-summary-sub { color: var(--text-dim); margin-bottom: 20px; }
.domain-bar-row { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; font-size: 13px; }
.domain-bar-row .label { width: 240px; flex-shrink: 0; color: var(--text-dim); }
.domain-bar-row .track { flex: 1; background: var(--bg); border-radius: 4px; height: 8px; overflow: hidden; }
.domain-bar-row .fill { height: 100%; background: var(--good); }
.domain-bar-row .fill.weak { background: var(--bad); }
.domain-bar-row .pct { width: 42px; text-align: right; color: var(--text-dim); }

.stat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-bottom: 20px;
}
@media (max-width: 640px) { .stat-grid { grid-template-columns: 1fr; } }
.stat-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  text-align: center;
}
.stat-box .num { font-size: 28px; font-weight: 800; color: var(--accent); }
.stat-box .lbl { font-size: 12.5px; color: var(--text-dim); margin-top: 2px; }

.history-row {
  display: flex; justify-content: space-between; padding: 8px 0;
  border-bottom: 1px solid var(--border); font-size: 13.5px;
}
.history-row:last-child { border-bottom: none; }
.history-row .date { color: var(--text-dim); }

.muted { color: var(--text-dim); font-size: 13px; }
.reset-link { color: var(--bad); cursor: pointer; font-size: 12.5px; text-decoration: underline; }