/* Phase 3A: quiet, readable defaults for the bs4_book HTML profile. */
:root {
  --uocub-blue: #1f5b87;
  --uocub-blue-dark: #164566;
  --uocub-blue-soft: #edf4f8;
  --uocub-ink: #252b33;
  --uocub-muted: #65717c;
  --uocub-rule: #d9e0e5;
  --uocub-panel: #f7f9fa;
  --uocub-code: #f4f6f8;
}

html { scroll-behavior: smooth; }

body {
  color: var(--uocub-ink);
  background: #fff;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  font-size: 17.5px;
  line-height: 1.62;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--uocub-blue);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.13em;
}

a:hover, a:focus {
  color: var(--uocub-blue-dark);
}

a:focus-visible {
  outline: 3px solid rgba(31, 91, 135, 0.3);
  outline-offset: 3px;
  border-radius: 2px;
}

main#content {
  max-width: 46rem;
  padding: 2.75rem 2.35rem 4rem;
}

main#content > .section:first-of-type > h1,
main#content > h1 {
  margin-top: 0;
}

h1, h2, h3, h4 {
  color: #182d3d;
  font-weight: 650;
  letter-spacing: -0.018em;
  line-height: 1.22;
}

h1 {
  margin: 2.7rem 0 1.35rem;
  font-size: clamp(2rem, 3vw, 2.55rem);
}

h2 {
  margin: 2.35rem 0 1rem;
  padding-top: 0.25rem;
  font-size: clamp(1.48rem, 2.2vw, 1.8rem);
}

h3 {
  margin: 1.8rem 0 0.7rem;
  font-size: 1.22rem;
}

p, ul, ol, dl { margin-bottom: 1.15rem; }
li + li { margin-top: 0.3rem; }

.sidebar-book {
  background: var(--uocub-panel);
  border-right: 1px solid var(--uocub-rule);
  padding: 1.7rem 1.2rem;
}

.sidebar-book h1 {
  font-size: 1.18rem;
  font-weight: 700;
  letter-spacing: -0.012em;
  line-height: 1.3;
  margin: 0 0 1.35rem;
}

.sidebar-book h1 a {
  color: #1d3547;
  text-decoration: none;
}

.sidebar-book .nav-link,
.sidebar-chapter .nav-link {
  border-radius: 0.25rem;
  color: #4d5c68;
  font-size: 0.88rem;
  line-height: 1.35;
  padding: 0.31rem 0.48rem;
}

.sidebar-book .nav-link:hover,
.sidebar-book .nav-link:focus,
.sidebar-chapter .nav-link:hover,
.sidebar-chapter .nav-link:focus {
  background: var(--uocub-blue-soft);
  color: var(--uocub-blue-dark);
}

.sidebar-book .nav-link.active,
.sidebar-chapter .nav-link.active {
  background: #dcebf3;
  color: var(--uocub-blue-dark);
  font-weight: 700;
}

.sidebar-chapter {
  border-left: 1px solid var(--uocub-rule);
  padding: 2.7rem 1rem;
}

.sidebar-chapter .nav-link { font-size: 0.82rem; }
.sidebar-chapter .navbar-nav .navbar-nav { margin-left: 0.45rem; }

nav[aria-label="Descargas PDF"] {
  align-items: center;
  border-bottom: 1px solid var(--uocub-rule);
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 1rem;
  margin: 0 0 2.2rem;
  padding: 0 0 1rem;
}

nav[aria-label="Descargas PDF"] a {
  font-size: 0.9rem;
  font-weight: 650;
  text-decoration: none;
}

nav[aria-label="Descargas PDF"] a::before {
  color: var(--uocub-muted);
  content: "↓ ";
}

.sourceCode, pre:not(.sourceCode) {
  background: var(--uocub-code);
  border: 1px solid #e0e5e9;
  border-left: 3px solid #b7cad8;
  border-radius: 0.25rem;
  font-size: 0.86rem;
  line-height: 1.5;
  margin: 1.35rem 0;
}

.sourceCode pre, pre {
  margin: 0;
  padding: 1rem 1.1rem;
}

code, kbd, samp { font-size: 0.88em; }

pre code { color: #273744; }

table, .table {
  border-color: var(--uocub-rule);
  font-size: 0.92rem;
  margin: 1.45rem 0;
}

table thead th, .table thead th {
  background: var(--uocub-blue-soft);
  border-bottom: 2px solid #bfd3e0;
  color: #25445a;
  font-weight: 700;
}

table td, table th, .table td, .table th { padding: 0.58rem 0.7rem; }
table tbody tr:nth-of-type(even) { background: rgba(31, 91, 135, 0.035); }

.caption, figcaption, p.caption {
  color: var(--uocub-muted);
  font-size: 0.9rem;
  line-height: 1.45;
  margin-top: 0.55rem;
}

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

footer.bg-primary { background-color: #214e70 !important; }

@media (max-width: 991.98px) {
  main#content { max-width: 48rem; padding: 2.1rem 1.65rem 3.2rem; }
  .sidebar-book { border-bottom: 1px solid var(--uocub-rule); border-right: 0; padding: 1.15rem 1.35rem; }
}

@media (max-width: 575.98px) {
  body { font-size: 16px; line-height: 1.58; }
  main#content { padding: 1.65rem 1rem 2.8rem; }
  h1 { font-size: 1.85rem; }
  h2 { font-size: 1.42rem; }
  .sidebar-book { padding: 1rem; }
  .sourceCode, pre:not(.sourceCode) { font-size: 0.78rem; }
  table, .table { font-size: 0.82rem; }
}