/* ================================================================
   0protocol.ai — Canonical Axiom Matrix stylesheet
   One source of truth for all 56 matrix pages.
   Two registers: Preferred (Blue + White) · Dark
   ================================================================ */

:root[data-theme="preferred"] {
  --bg: #ffffff;
  --paper: #ffffff;
  --card-bg: #f0f5fc;
  --text: #0a2347;
  --heading: #050f26;
  --primary: #2a5080;
  --accent: #c48b3f;
  --gold: #b3883b;
  --ice: #5e9ad4;
  --border: #d8e2f0;
  --muted: #6a7a95;
  --header-bg: rgba(255, 255, 255, 0.88);
  --header-border: #d8e2f0;
  --dropdown-bg: #eaf2fb;
  --dropdown-border: #bcd0ea;
  --rule: #d8e2f0;
  --shadow: 0 4px 20px rgba(10, 35, 71, 0.06);
}
:root[data-theme="dark"] {
  --bg: #050a14;
  --paper: #0e1a2e;
  --card-bg: #152338;
  --text: #dde6f2;
  --heading: #f4f8ff;
  --primary: #7fb0e0;
  --accent: #e0b870;
  --gold: #d4b06b;
  --ice: #7fb0e0;
  --border: #1f2d44;
  --muted: #8599b5;
  --header-bg: rgba(10, 18, 35, 0.88);
  --header-border: #1f2d44;
  --dropdown-bg: #122038;
  --dropdown-border: #243654;
  --rule: #1f2d44;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  background: var(--bg);
  color: var(--text);
  font-family: Charter, 'Bitstream Charter', 'Iowan Old Style', Georgia, serif;
  line-height: 1.75;
  font-size: 17px;
  text-rendering: optimizeLegibility;
  transition: background 0.3s, color 0.3s;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--accent); text-decoration: underline; }

/* ------------------- HEADER (universal) ------------------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--header-border);
}
.header-inner {
  max-width: 1380px; margin: 0 auto;
  padding: 14px 28px;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.brand {
  font-family: Charter, Georgia, serif;
  font-size: 1.15rem; font-weight: 600;
  color: var(--heading); letter-spacing: 0.02em;
}
.brand a { color: var(--heading); }
.brand a:hover { color: var(--primary); text-decoration: none; }
.nav { display: flex; align-items: center; gap: 28px; }
.nav a {
  color: var(--text);
  font-size: 0.92rem; letter-spacing: 0.08em; text-transform: uppercase;
  font-weight: 500;
}
.nav a:hover { color: var(--primary); text-decoration: none; }
.nav a.current { color: var(--accent); }

/* Dropdown */
.nav-item {
  position: relative;
  display: inline-flex;
  align-items: center;
}
.nav-item > a .caret {
  display: inline-block;
  margin-left: 4px;
  font-size: 0.7em;
  transition: transform 0.2s;
}
.nav-item:hover > a .caret { transform: rotate(180deg); }
.dropdown-menu {
  position: absolute;
  top: 100%;
  left: -14px;
  margin-top: 8px;
  min-width: 240px;
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: 6px;
  box-shadow: var(--shadow);
  padding: 10px 0;
  list-style: none;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s;
  z-index: 110;
}
.nav-item:hover .dropdown-menu,
.nav-item:focus-within .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.dropdown-menu li { margin: 0; }
.dropdown-menu a {
  display: block;
  padding: 10px 18px;
  color: var(--text);
  font-size: 0.88rem;
  letter-spacing: 0.03em;
  text-transform: none;
  font-weight: 400;
  line-height: 1.3;
  transition: background 0.15s, color 0.15s;
}
.dropdown-menu a:hover {
  background: var(--card-bg);
  color: var(--accent);
  text-decoration: none;
}
.dropdown-menu .item-label {
  display: block;
  font-weight: 500;
  color: var(--heading);
}
.dropdown-menu .item-sub {
  display: block;
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 2px;
  font-style: italic;
}
.dropdown-menu a:hover .item-label { color: var(--accent); }

.view-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px;
  background: transparent;
  border: 1px solid var(--dropdown-border);
  border-radius: 50%;
  cursor: pointer; color: var(--text);
  transition: background 0.2s, color 0.2s, border-color 0.2s;
  padding: 0;
}
.view-icon:hover { background: var(--dropdown-bg); color: var(--accent); border-color: var(--accent); }
.view-icon svg { width: 18px; height: 18px; display: block; }
.view-icon .icon-moon { display: none; }
:root[data-theme="dark"] .view-icon .icon-sun { display: none; }
:root[data-theme="dark"] .view-icon .icon-moon { display: block; }

/* ------------------- LAYOUT (sidebar + content) ------------------- */
.layout {
  display: flex;
  max-width: 1380px;
  margin: 0 auto;
  padding: 40px 20px;
  gap: 40px;
}
.sidebar {
  flex: 0 0 320px;
  position: sticky;
  top: 85px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  padding-right: 18px;
  font-size: 0.88em;
  border-right: 1px solid var(--border);
}
.sidebar h4 {
  text-transform: uppercase;
  letter-spacing: 1.2px;
  font-size: 0.82em;
  color: var(--primary);
  margin-top: 0;
  margin-bottom: 12px;
  border-bottom: 2px solid var(--gold);
  padding-bottom: 6px;
}
.sidebar ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}
.sidebar li {
  margin-bottom: 8px;
  line-height: 1.35;
}
.sidebar a {
  color: var(--text);
  text-decoration: none;
  transition: color 0.15s ease;
}
.sidebar a:hover { color: var(--accent); text-decoration: none; }
.sidebar .toc-part {
  font-weight: bold;
  margin-top: 16px;
  color: var(--primary);
  font-size: 0.95em;
  letter-spacing: 0.5px;
}

.content {
  flex: 1;
  min-width: 0;
  background: var(--paper);
  padding: 60px 80px;
  border-radius: 6px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

/* ------------------- BOOK TITLE BLOCK ------------------- */
.book-title-block {
  text-align: center;
  border-bottom: 2px solid var(--border);
  padding-bottom: 40px;
  margin-bottom: 45px;
}
.book-title-block h1 {
  font-size: 2.2em;
  letter-spacing: 1px;
  color: var(--heading);
  margin: 0 0 12px 0;
  font-weight: normal;
  text-transform: uppercase;
  line-height: 1.25;
}
.book-title-block .subtitle {
  font-size: 1.15em;
  color: var(--muted);
  font-style: italic;
  margin-bottom: 18px;
}
.book-title-block .meta {
  font-size: 0.88em;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* ------------------- PARTS AND CHAPTERS ------------------- */
.part-banner {
  background: var(--card-bg);
  border-left: 5px solid var(--primary);
  padding: 16px 24px;
  margin-top: 50px;
  margin-bottom: 25px;
}
.part-banner h2 {
  margin: 0;
  font-size: 1.3em;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--primary);
}
.chapter-header {
  margin-top: 35px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}
.chapter-header h3 {
  margin: 0;
  font-size: 1.15em;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--heading);
}

p {
  margin: 1.15em 0;
  text-align: justify;
  color: var(--text);
}
strong { color: var(--heading); }
em { color: var(--text); }

ul, ol {
  margin: 1em 0 1.5em 20px;
  padding-left: 20px;
}
li { margin-bottom: 8px; }

blockquote {
  margin: 25px 0;
  padding: 18px 25px;
  background-color: var(--card-bg);
  border-left: 4px solid var(--gold);
  font-style: italic;
  color: var(--text);
}

.callout-box {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-left: 4px solid var(--primary);
  padding: 20px 24px;
  margin: 25px 0;
  border-radius: 4px;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 25px 0;
  font-size: 0.95em;
  background: var(--paper);
}
th, td {
  border: 1px solid var(--border);
  padding: 12px 14px;
  text-align: left;
  color: var(--text);
}
th {
  background-color: var(--card-bg);
  color: var(--primary);
  font-weight: bold;
}

/* ------------------- FOOTER ------------------- */
.matrix-footer {
  max-width: 1380px;
  margin: 0 auto;
  padding: 30px 28px 50px;
  text-align: center;
  color: var(--muted);
  font-size: 0.88rem;
  border-top: 1px solid var(--border);
}
.matrix-footer a { color: var(--primary); }
.matrix-footer p { margin-bottom: 4px; }

/* ------------------- RESPONSIVE ------------------- */
@media (max-width: 960px) {
  .header-inner { flex-wrap: wrap; gap: 14px; padding: 12px 18px; }
  .nav { gap: 16px; }
  .nav a { font-size: 0.8rem; }
  .layout {
    flex-direction: column;
    padding: 15px;
    gap: 20px;
  }
  .sidebar {
    position: static;
    max-height: none;
    overflow-y: visible;
    border-right: none;
    border-bottom: 1px solid var(--border);
    padding-bottom: 20px;
    padding-right: 0;
  }
  .content {
    padding: 30px 22px;
  }
  .book-title-block h1 { font-size: 1.6em; }
}