:root {
  --fg: #1f2937;
  --muted: #6b7280;
  --accent: #1a4d3a;
  --accent-light: #2d7a4f;
  --amber-bg: #fdf6e3;
  --amber-border: #d4a017;
  --task-bg: #f4f9f5;
  --task-border: #2d7a4f;
  --code-bg: #f5eecc;
  --neg: #b03a3a;
  --pos: #2d7a4f;
  --zero: #6b7280;
  --page-bg: #fdfaf0;
  --panel-warm: #faf5e4;
}

* { box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  max-width: 920px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
  color: var(--fg);
  line-height: 1.65;
  font-size: 16px;
  background: var(--page-bg);
  min-height: 100vh;
}
html { background: var(--page-bg); }

/* Top nav */
.kb-nav {
  padding: 0.6rem 0;
  border-bottom: 1px solid #e5e7eb;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}
.kb-nav a {
  color: var(--accent);
  text-decoration: none;
}
.kb-nav a:hover { text-decoration: underline; }

/* Page header */
header.page {
  border-bottom: 2px solid var(--accent);
  padding-bottom: 1rem;
  margin-bottom: 2rem;
}
header.page .course {
  color: var(--muted);
  font-size: 0.9rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
header.page h1 {
  color: var(--accent);
  margin: 0.25rem 0 0.5rem;
  font-size: 2rem;
}

h2 {
  color: var(--accent);
  margin-top: 2.5rem;
  border-bottom: 1px solid #e5e7eb;
  padding-bottom: 0.3rem;
}
h3 { color: var(--accent-light); margin-top: 1.5rem; }
p { margin: 0.75rem 0; }

code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 3px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.92em;
}

/* Callouts */
.example {
  background: var(--amber-bg);
  border-left: 4px solid var(--amber-border);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  border-radius: 0 4px 4px 0;
}
.example > strong:first-child { color: #8a6d0b; }

.task {
  background: var(--task-bg);
  border-left: 4px solid var(--task-border);
  padding: 1rem 1.25rem 1rem 2.5rem;
  margin: 1.5rem 0;
  border-radius: 0 4px 4px 0;
  position: relative;
}
.task::before {
  content: "→";
  position: absolute;
  left: 1rem;
  top: 1rem;
  color: var(--task-border);
  font-weight: bold;
  font-size: 1.1rem;
}

.takeaway {
  background: linear-gradient(180deg, #f0f7f3 0%, #ffffff 100%);
  border: 1px solid var(--accent-light);
  padding: 1.25rem 1.5rem;
  border-radius: 8px;
  margin: 2rem 0;
}
.takeaway h3 { margin-top: 0; }
.takeaway ul { margin: 0.5rem 0; padding-left: 1.5rem; }
.takeaway li { margin: 0.4rem 0; }

/* Article listing (homepage) */
.article-list {
  list-style: none;
  padding: 0;
  margin: 1rem 0;
}
.article-list li {
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin-bottom: 1rem;
  background: #fff;
}
.article-list a.title {
  color: var(--accent);
  text-decoration: none;
  font-size: 1.15rem;
  font-weight: 600;
}
.article-list a.title:hover { text-decoration: underline; }
.article-list .meta {
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 4px;
  letter-spacing: 0.03em;
}
.article-list p {
  margin: 0.5rem 0 0;
  color: var(--fg);
  font-size: 0.95rem;
}

/* Wheel interactives */
.wheels {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}
.wheel-box {
  border: 1px solid #e5e7eb;
  border-radius: 10px;
  padding: 1rem 1rem 1.25rem;
  text-align: center;
  background: #fff;
}
.wheel-box h3 {
  margin: 0.25rem 0 0.5rem;
  font-size: 1.05rem;
  color: var(--accent);
}
.wheel-box .subtitle {
  color: var(--muted);
  font-size: 0.88rem;
  margin-bottom: 0.75rem;
}
.wheel-svg { max-width: 100%; height: auto; }
.wheel-info {
  margin-top: 0.5rem;
  padding: 0.6rem 0.5rem;
  background: var(--panel-warm);
  border-radius: 4px;
  font-family: "SF Mono", Menlo, monospace;
  min-height: 4.5rem;
}
.wheel-info .val {
  display: block;
  font-size: 1.8rem;
  font-weight: bold;
  line-height: 1.1;
}
.wheel-info .pat {
  color: var(--muted);
  font-size: 0.85rem;
  display: block;
  margin-top: 2px;
}
.wheel-info .status {
  color: var(--fg);
  font-size: 0.82rem;
  margin-top: 4px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  min-height: 1.2rem;
}
.wheel-info .status .landed {
  color: var(--pos);
  font-weight: bold;
}
.controls {
  margin-top: 0.75rem;
  display: flex;
  gap: 0.4rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
button {
  background: var(--accent);
  color: white;
  border: none;
  padding: 0.5rem 0.9rem;
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.9rem;
  font-family: inherit;
}
button:hover:not(:disabled) { background: var(--accent-light); }
button:disabled { background: #9ca3af; cursor: not-allowed; }
button.secondary {
  background: #fff;
  color: var(--accent);
  border: 1px solid var(--accent);
}
button.secondary:hover:not(:disabled) { background: #f3f4f6; }

/* Formulas & badges */
.formula-box {
  background: #fff;
  border: 2px dashed var(--accent-light);
  padding: 1rem;
  text-align: center;
  font-size: 1.15rem;
  border-radius: 6px;
  margin: 1rem 0;
  font-family: "SF Mono", Menlo, monospace;
}
.equation-badge {
  display: inline-block;
  background: #fff;
  border: 1px solid #d1d5db;
  padding: 4px 10px;
  border-radius: 4px;
  font-family: "SF Mono", Menlo, monospace;
  font-weight: bold;
  font-size: 1.05rem;
  margin: 0 4px;
}

/* Tables */
table.compact {
  border-collapse: collapse;
  margin: 1rem auto;
  font-family: "SF Mono", Menlo, monospace;
  font-size: 0.92rem;
}
table.compact th, table.compact td {
  border: 1px solid #d1d5db;
  padding: 4px 12px;
  text-align: center;
}
table.compact th {
  background: var(--panel-warm);
  font-weight: 600;
  font-family: inherit;
}

/* Quiz */
.quiz {
  border: 1px solid #d1d5db;
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  background: var(--panel-warm);
}
.quiz p.question { margin: 0 0 0.75rem; font-weight: 500; }
.quiz-controls {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  flex-wrap: wrap;
}
.quiz input {
  font-family: "SF Mono", Menlo, monospace;
  font-size: 1rem;
  padding: 6px 10px;
  width: 140px;
  border: 1px solid #cbd5e1;
  border-radius: 4px;
  background: #fff;
}
.quiz input:focus {
  outline: 2px solid var(--accent-light);
  outline-offset: 1px;
}
.feedback {
  margin-top: 0.6rem;
  min-height: 1.4rem;
  font-size: 0.92rem;
}
.feedback.correct { color: var(--pos); font-weight: bold; }
.feedback.incorrect { color: var(--neg); }
.feedback.hint { color: var(--muted); font-style: italic; }

/* Footer */
footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid #e5e7eb;
  color: var(--muted);
  font-size: 0.88rem;
}