:root {
  --ink: #18181b;
  --body: #3f3f46;
  --muted: #71717a;
  --line: #e4e4e7;
  --accent: #7c3aed;
  --accent-soft: #f5f0ff;
  --code-bg: #18141f;
}

* {
  box-sizing: border-box;
}

html {
  -webkit-print-color-adjust: exact;
  print-color-adjust: exact;
}

body {
  margin: 0;
  background: #f4f4f5;
  color: var(--body);
  font-family: "Figtree", system-ui, sans-serif;
  font-size: 15px;
  line-height: 1.7;
}

a {
  color: var(--accent);
}

.fc-toolbar {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.7rem 1.25rem;
  background: #0b0a10;
  color: #d4d4d8;
  font-size: 0.85rem;
}

.fc-toolbar a {
  color: #c8a2ff;
  text-decoration: none;
  white-space: nowrap;
}

.fc-toolbar span {
  flex: 1;
  text-align: center;
}

.fc-toolbar button {
  border: 0;
  border-radius: 999px;
  padding: 0.55rem 1.1rem;
  background: #a855f7;
  color: #fff;
  font: 700 0.85rem "Figtree", sans-serif;
  cursor: pointer;
  white-space: nowrap;
}

.fc-doc {
  max-width: 820px;
  margin: 2rem auto;
  padding: 3rem 3.25rem;
  background: #fff;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.08);
}

/* Cover + contents */
.fc-cover {
  min-height: 70vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  border-left: 6px solid var(--accent);
  padding-left: 2rem;
}

.fc-brand {
  margin: 0 0 1rem;
  color: var(--accent);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.8rem;
}

.fc-cover h1 {
  margin: 0 0 0.75rem;
  color: var(--ink);
  font-size: 3rem;
  line-height: 1.05;
  letter-spacing: -0.03em;
}

.fc-tagline {
  margin: 0 0 1.5rem;
  font-size: 1.25rem;
  color: var(--body);
}

.fc-facts {
  margin: 0.15rem 0;
  color: var(--muted);
}

.fc-author {
  margin-top: 3rem;
  color: var(--ink);
  font-weight: 600;
}

.fc-toc {
  break-before: page;
  padding-top: 1rem;
}

.fc-toc h2 {
  color: var(--ink);
  font-size: 1.8rem;
  margin: 0 0 1.25rem;
}

.fc-toc ol {
  list-style: none;
  margin: 0;
  padding: 0;
}

.fc-toc-section {
  margin-bottom: 1.25rem;
}

.fc-toc-section > strong {
  display: block;
  margin-bottom: 0.35rem;
  color: var(--accent);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.fc-toc-section li a {
  display: flex;
  gap: 0.9rem;
  padding: 0.4rem 0;
  border-bottom: 1px dotted var(--line);
  color: var(--ink);
  text-decoration: none;
}

.fc-toc-section li a span {
  color: var(--muted);
  font-family: "JetBrains Mono", monospace;
  font-size: 0.85rem;
}

/* Lessons */
.fc-lesson {
  break-before: page;
  padding-top: 2.5rem;
}

.fc-kicker {
  margin: 0 0 0.4rem;
  color: var(--accent);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.fc-lesson > h1 {
  margin: 0 0 0.75rem;
  color: var(--ink);
  font-size: 2.1rem;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.course-lede {
  font-size: 1.1rem;
  color: var(--ink);
  margin: 0 0 0.4rem;
}

.course-meta {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 0 0 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}

.fc-body h2 {
  color: var(--ink);
  font-size: 1.45rem;
  margin: 2rem 0 0.6rem;
  break-after: avoid;
}

.fc-body h3 {
  color: var(--ink);
  font-size: 1.15rem;
  margin: 1.5rem 0 0.5rem;
  break-after: avoid;
}

.fc-body p,
.fc-body li {
  orphans: 3;
  widows: 3;
}

.fc-body code {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.86em;
  background: var(--accent-soft);
  color: #5b21b6;
  padding: 0.08em 0.35em;
  border-radius: 4px;
}

/* Code + output */
.course-code {
  margin: 1.1rem 0;
  border-radius: 10px;
  overflow: hidden;
  background: var(--code-bg);
  break-inside: avoid;
}

.course-code-bar {
  padding: 0.4rem 0.9rem;
  background: #2a2236;
  color: #c8a2ff;
  font: 600 0.72rem "JetBrains Mono", monospace;
  letter-spacing: 0.05em;
}

.course-copy {
  display: none;
}

.course-code pre {
  margin: 0;
  padding: 0.9rem 1rem;
  font-size: 0.8rem;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

.course-code pre code {
  background: none;
  color: #ede9fe;
  padding: 0;
  font-size: 0.8rem;
  line-height: 1.6;
}

.course-output {
  margin: -0.6rem 0 1.1rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--line);
  border-left: 4px solid #22c55e;
  border-radius: 0 0 10px 10px;
  background: #fafafa;
  color: var(--ink);
  font: 0.78rem/1.6 "JetBrains Mono", monospace;
  white-space: pre-wrap;
  word-break: break-word;
  break-inside: avoid;
}

/* Callouts, definitions, tables, takeaways */
.callout,
.course-def,
.course-takeaways {
  margin: 1.1rem 0;
  padding: 0.85rem 1.1rem;
  border-radius: 10px;
  border: 1px solid var(--line);
  border-left-width: 4px;
  break-inside: avoid;
}

.callout p:last-child,
.course-def p:last-child {
  margin-bottom: 0;
}

.callout.note { border-left-color: #3b82f6; background: #eff6ff; }
.callout.tryit { border-left-color: var(--accent); background: var(--accent-soft); }
.callout.watch { border-left-color: #f59e0b; background: #fffbeb; }
.course-def { border-left-color: var(--accent); background: var(--accent-soft); }
.course-takeaways { border-left-color: #22c55e; background: #f0fdf4; }

.callout-label,
.course-def-term {
  display: block;
  margin-bottom: 0.3rem;
  color: var(--ink);
  font-weight: 800;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.course-def p {
  margin: 0;
}

.course-takeaways ul {
  margin: 0;
  padding-left: 1.2rem;
}

.course-table-wrap {
  margin: 1.1rem 0;
  break-inside: avoid;
}

.course-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.86rem;
}

.course-table th,
.course-table td {
  padding: 0.5rem 0.65rem;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.course-table th {
  background: var(--accent-soft);
  color: var(--ink);
}

.fc-end {
  break-before: avoid;
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
}

@media (max-width: 700px) {
  .fc-toolbar span {
    display: none;
  }
  .fc-toolbar {
    justify-content: space-between;
  }
  .fc-doc {
    margin: 0;
    padding: 1.5rem 1.1rem;
  }
  .fc-cover h1 {
    font-size: 2.2rem;
  }
}

@page {
  size: A4;
  margin: 16mm 15mm 18mm;
}

@media print {
  body {
    background: #fff;
    font-size: 11pt;
  }
  .fc-toolbar {
    display: none;
  }
  .fc-doc {
    max-width: none;
    margin: 0;
    padding: 0;
    box-shadow: none;
  }
  .fc-cover {
    min-height: 240mm;
  }
  .fc-lesson {
    padding-top: 0;
  }
  a {
    color: inherit;
    text-decoration: none;
  }
}