/* Bitcoin 101 course site — The Boy Who Cried Bitcoin / 21 Million Publishing House
   Self-contained. No external fonts, no CDNs. System font stack only. */

:root {
  --orange: #F7931A;
  --orange-dark: #C9760C;
  --ink: #1A1A1A;
  --ink-soft: #4A4A4A;
  --paper: #FFFFFF;
  --paper-soft: #FAF7F2;
  --line: #E7E1D8;
  --danger-bg: #FFF4E5;
  --danger-border: #F7931A;
  --max-width: 720px;
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #F2EFE9;
    --ink-soft: #C9C2B4;
    --paper: #14120F;
    --paper-soft: #1C1913;
    --line: #322C22;
    --danger-bg: #2A1F0E;
    --danger-border: #F7931A;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

p, h1, h2, h3, li, blockquote {
  overflow-wrap: break-word;
  word-wrap: break-word;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  font-size: 17px;
  overflow-x: hidden;
  width: 100%;
}

a { color: var(--orange-dark); text-decoration-thickness: 1.5px; }
@media (prefers-color-scheme: dark) {
  a { color: var(--orange); }
}

img, svg { max-width: 100%; }

/* ---------- header ---------- */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 20px;
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 10;
  max-width: 100%;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
  min-width: 0;
  overflow: hidden;
}

.logo-mark {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  min-width: 0;
  overflow: hidden;
}

.brand-text strong {
  font-size: 1rem;
  color: var(--ink);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.brand-text small {
  font-size: 0.72rem;
  color: var(--ink-soft);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.top-nav {
  flex-shrink: 0;
}

.top-nav a {
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
}

/* ---------- layout ---------- */

.page {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 28px 20px 60px;
  width: 100%;
}

/* ---------- hero (index) ---------- */

.hero {
  text-align: center;
  padding: 24px 0 8px;
}

.hero h1 {
  font-size: 2.4rem;
  margin: 0 0 6px;
  letter-spacing: -0.02em;
}

.hero-sub {
  font-size: 1.15rem;
  color: var(--ink-soft);
  margin: 0 0 18px;
}

.hero-lede {
  max-width: 560px;
  margin: 0 auto;
  color: var(--ink-soft);
}

/* ---------- NFA banner ---------- */

.nfa-banner {
  background: var(--danger-bg);
  border: 1px solid var(--danger-border);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 0.92rem;
  margin: 22px 0;
  color: var(--ink);
}

/* ---------- module list ---------- */

.module-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 26px 0;
}

.module-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--ink);
  background: var(--paper-soft);
  transition: border-color 0.15s ease;
  min-width: 0;
}

.module-card:hover {
  border-color: var(--orange);
}

.module-card--pending {
  opacity: 0.65;
}

.module-index {
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--orange-dark);
  min-width: 28px;
  flex-shrink: 0;
}

@media (prefers-color-scheme: dark) {
  .module-index { color: var(--orange); }
}

.module-body {
  display: flex;
  flex-direction: column;
  gap: 3px;
  flex: 1;
  min-width: 0;
}

.module-title {
  font-weight: 700;
  overflow-wrap: break-word;
}

.module-teaser {
  font-size: 0.88rem;
  color: var(--ink-soft);
  overflow-wrap: break-word;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.module-arrow {
  color: var(--orange-dark);
  font-weight: 700;
  flex-shrink: 0;
}

.badge-soon {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  background: var(--line);
  color: var(--ink-soft);
  border-radius: 999px;
  padding: 2px 8px;
  margin-left: 6px;
  vertical-align: middle;
}

/* ---------- rule callout ---------- */

.rule-callout {
  border-left: 4px solid var(--orange);
  padding: 4px 0 4px 16px;
  margin: 30px 0;
}

.rule-callout h2 {
  font-size: 1.05rem;
  margin: 0 0 6px;
}

.rule-callout p {
  margin: 0;
  color: var(--ink-soft);
}

/* ---------- module page ---------- */

.module-eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--orange-dark);
  margin: 22px 0 4px;
}

@media (prefers-color-scheme: dark) {
  .module-eyebrow { color: var(--orange); }
}

.module-content h1 {
  font-size: 1.8rem;
  margin: 4px 0 18px;
  letter-spacing: -0.01em;
}

.module-content h2 {
  font-size: 1.25rem;
  margin: 28px 0 10px;
}

.module-content h3 {
  font-size: 1.05rem;
  margin: 20px 0 8px;
}

.module-content p {
  margin: 0 0 16px;
}

.module-content ul,
.module-content ol {
  margin: 0 0 16px;
  padding-left: 1.3em;
}

.module-content li {
  margin-bottom: 6px;
}

.module-content blockquote {
  border-left: 3px solid var(--orange);
  margin: 18px 0;
  padding: 2px 0 2px 14px;
  color: var(--ink-soft);
  font-style: italic;
}

.module-content code {
  background: var(--paper-soft);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 1px 5px;
  font-size: 0.9em;
}

.module-content strong {
  color: var(--ink);
}

.coming-soon {
  background: var(--paper-soft);
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  padding: 18px;
  color: var(--ink-soft);
}

/* ---------- pager ---------- */

.pager {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 36px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 0.92rem;
  font-weight: 600;
}

.pager-link {
  text-decoration: none;
  white-space: nowrap;
}

.pager-home {
  color: var(--ink-soft);
  font-weight: 500;
}

/* ---------- footer ---------- */

.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 20px 20px 50px;
  border-top: 1px solid var(--line);
}

.footer-nfa {
  font-size: 0.82rem;
  color: var(--ink-soft);
  margin-bottom: 14px;
}

.footer-meta {
  font-size: 0.78rem;
  color: var(--ink-soft);
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

/* ---------- print ---------- */

@media print {
  .site-header, .pager, .top-nav { display: none; }
}