/* CXOS Reference Documentation — shared styles */

:root {
  --bg: #f6f7fb;
  --surface: #ffffff;
  --surface-alt: #f0f2f8;
  --border: #e2e5ee;
  --text: #1b1f2e;
  --text-muted: #5a6072;
  --brand: #3454d1;
  --brand-dark: #26399e;
  --brand-light: #e8ecfc;
  --accent-blue: #2b7fd6;
  --accent-teal: #0f9b8e;
  --accent-green: #2e9e5b;
  --accent-orange: #d9822b;
  --accent-pink: #c23b6d;
  --accent-purple: #6a4fc2;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(20, 24, 40, 0.06), 0 4px 16px rgba(20, 24, 40, 0.06);
  --shadow-hover: 0 4px 10px rgba(20, 24, 40, 0.08), 0 10px 28px rgba(20, 24, 40, 0.10);
  --header-h: 60px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12141c;
    --surface: #191c27;
    --surface-alt: #20232f;
    --border: #2b2f3d;
    --text: #e9ebf3;
    --text-muted: #9aa0b4;
    --brand: #7b93ff;
    --brand-dark: #a6b6ff;
    --brand-light: #232a4d;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 16px rgba(0, 0, 0, 0.25);
    --shadow-hover: 0 4px 10px rgba(0, 0, 0, 0.35), 0 10px 28px rgba(0, 0, 0, 0.3);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}

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

img { max-width: 100%; display: block; }

/* ---------- Header / Nav ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 20px;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 16px;
  color: var(--text);
  white-space: nowrap;
}
.brand:hover { text-decoration: none; }

.brand-mark {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--brand), var(--accent-purple));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 800;
  flex-shrink: 0;
}

.brand-sub {
  font-weight: 400;
  font-size: 12px;
  color: var(--text-muted);
  display: none;
}
@media (min-width: 720px) { .brand-sub { display: inline; } }

nav.main-nav {
  flex: 1;
  min-width: 0;
}

.nav-list {
  list-style: none;
  display: flex;
  margin: 0;
  padding: 0;
  height: var(--header-h);
  overflow-x: auto;
  scrollbar-width: none;
}
.nav-list::-webkit-scrollbar { display: none; }

.nav-list > li {
  position: relative;
  display: flex;
  align-items: stretch;
}

.nav-list > li > a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 12px;
  color: var(--text);
  font-size: 13.5px;
  font-weight: 600;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
}
.nav-list > li > a:hover,
.nav-list > li.active > a {
  color: var(--brand);
  border-bottom-color: var(--brand);
  text-decoration: none;
}

.nav-caret { font-size: 9px; opacity: 0.6; transform: translateY(1px); }

.dropdown {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 260px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0 0 var(--radius) var(--radius);
  box-shadow: var(--shadow-hover);
  padding: 8px;
  display: none;
  z-index: 200;
}

.nav-list > li:hover .dropdown,
.nav-list > li.open .dropdown {
  display: block;
}

.dropdown a {
  display: flex;
  flex-direction: column;
  gap: 1px;
  padding: 8px 10px;
  border-radius: 6px;
  color: var(--text);
  font-size: 13px;
  font-weight: 600;
}
.dropdown a:hover { background: var(--brand-light); color: var(--brand-dark); text-decoration: none; }
.dropdown a span.desc {
  font-weight: 400;
  font-size: 11.5px;
  color: var(--text-muted);
}

.nav-toggle {
  display: none;
  border: none;
  background: none;
  font-size: 20px;
  color: var(--text);
  cursor: pointer;
  padding: 4px 8px;
}

@media (max-width: 860px) {
  .nav-toggle { display: block; }
  nav.main-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--surface);
    display: none;
    overflow-y: auto;
  }
  nav.main-nav.open { display: block; }
  .nav-list { flex-direction: column; height: auto; }
  .nav-list > li { flex-direction: column; }
  .nav-list > li > a { height: 46px; border-bottom: 1px solid var(--border); }
  .dropdown {
    position: static;
    box-shadow: none;
    border: none;
    border-bottom: 1px solid var(--border);
    border-radius: 0;
    display: none;
    background: var(--surface-alt);
  }
  .nav-list > li.open .dropdown { display: block; }
}

/* ---------- Layout ---------- */

.page {
  max-width: 1180px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

.breadcrumb {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 18px;
}
.breadcrumb a { color: var(--text-muted); }
.breadcrumb .sep { margin: 0 6px; opacity: 0.5; }
.breadcrumb .current { color: var(--text); font-weight: 600; }

/* ---------- Hero ---------- */

.hero {
  padding: 40px 0 8px;
}
.hero-eyebrow {
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--brand);
  margin: 0 0 8px;
}
.hero h1 {
  font-size: clamp(26px, 4vw, 38px);
  margin: 0 0 10px;
  letter-spacing: -0.01em;
}
.hero p.lead {
  font-size: 16px;
  color: var(--text-muted);
  max-width: 720px;
  margin: 0;
}

/* ---------- Badge strip ---------- */

.badge-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 10px;
  margin: 28px 0 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
}
.badge {
  display: flex;
  align-items: flex-start;
  gap: 10px;
}
.badge .icon {
  font-size: 18px;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--brand-light);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.badge .title { font-size: 13px; font-weight: 700; }
.badge .desc { font-size: 11.5px; color: var(--text-muted); }

/* ---------- Section heading ---------- */

.section {
  margin-top: 56px;
}
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.section-head h2 {
  font-size: 22px;
  margin: 0;
}
.section-head p {
  margin: 4px 0 0;
  color: var(--text-muted);
  font-size: 14px;
}

/* ---------- Module cards (homepage) ---------- */

.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

.module-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  transition: box-shadow 0.15s ease, transform 0.15s ease;
  display: flex;
  flex-direction: column;
  gap: 10px;
  border-top: 3px solid var(--card-accent, var(--brand));
}
.module-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
  text-decoration: none;
}
.module-card .step {
  font-size: 11px;
  font-weight: 800;
  color: var(--card-accent, var(--brand));
  letter-spacing: 0.05em;
}
.module-card h3 {
  margin: 0;
  font-size: 17px;
  color: var(--text);
}
.module-card p {
  margin: 0;
  font-size: 13.5px;
  color: var(--text-muted);
  flex: 1;
}
.module-card .tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 4px;
}
.module-card .tags span {
  font-size: 11px;
  background: var(--surface-alt);
  color: var(--text-muted);
  padding: 3px 8px;
  border-radius: 999px;
}
.module-card .go {
  font-size: 12.5px;
  font-weight: 700;
  color: var(--card-accent, var(--brand));
}

/* ---------- Diagram frame ---------- */

.diagram-frame {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  box-shadow: var(--shadow);
}
.diagram-frame img { border-radius: 6px; cursor: zoom-in; }
.diagram-caption {
  font-size: 12.5px;
  color: var(--text-muted);
  text-align: center;
  margin-top: 10px;
}

/* ---------- High-Level Design (HLD) diagram ---------- */

.hld-diagram {
  display: flex;
  align-items: stretch;
  gap: 0;
  overflow-x: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px 14px;
}
.hld-node {
  flex: 1 0 150px;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  background: var(--surface-alt);
  margin: 0 4px;
}
.hld-node.origin {
  border-color: var(--card-accent, var(--brand));
  border-width: 2px;
  background: var(--brand-light);
}
.hld-node .stage-label {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}
.hld-node .stage-name {
  font-weight: 700;
  font-size: 13.5px;
  margin-top: 3px;
  color: var(--text);
}
.hld-node .stage-detail {
  font-size: 11.5px;
  color: var(--text-muted);
  margin-top: 4px;
  line-height: 1.4;
}
.hld-arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 22px;
  color: var(--text-muted);
  font-size: 15px;
}
.hld-caption {
  font-size: 12.5px;
  color: var(--text-muted);
  margin-top: 10px;
}

/* ---------- Code block ---------- */

.code-block {
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 12.5px;
  line-height: 1.6;
  overflow-x: auto;
  white-space: pre;
  color: var(--text);
  margin: 0;
}

/* ---------- Handbook section variants ---------- */

.handbook-block {
  margin-top: 14px;
}
.handbook-block h3 {
  font-size: 12.5px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin: 0 0 8px;
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(10, 12, 20, 0.85);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 30px;
  z-index: 1000;
  cursor: zoom-out;
}
.lightbox.open { display: flex; }
.lightbox img {
  max-width: 100%;
  max-height: 100%;
  border-radius: 8px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
}

/* ---------- Module page layout ---------- */

.module-page {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 32px;
  align-items: start;
}
@media (max-width: 860px) {
  .module-page { grid-template-columns: 1fr; }
}

.side-nav {
  position: sticky;
  top: calc(var(--header-h) + 20px);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  box-shadow: var(--shadow);
}
.side-nav .label {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 8px;
}
.side-nav ul { list-style: none; margin: 0; padding: 0; }
.side-nav li a {
  display: block;
  padding: 7px 8px;
  border-radius: 6px;
  font-size: 13.5px;
  color: var(--text);
  border-left: 2px solid transparent;
}
.side-nav li a:hover { background: var(--surface-alt); text-decoration: none; }
.side-nav li a.active {
  color: var(--brand);
  border-left-color: var(--brand);
  background: var(--brand-light);
  font-weight: 600;
}

.module-intro {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--card-accent, var(--brand));
  border-radius: var(--radius);
  padding: 20px 22px;
  box-shadow: var(--shadow);
  margin-bottom: 8px;
}
.module-intro .step {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--card-accent, var(--brand));
  text-transform: uppercase;
}
.module-intro h1 { margin: 6px 0 8px; font-size: 26px; }
.module-intro p { margin: 0; color: var(--text-muted); font-size: 14.5px; max-width: 760px; }

.submodule {
  scroll-margin-top: calc(var(--header-h) + 20px);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  margin-top: 20px;
  box-shadow: var(--shadow);
}
.submodule h2 {
  margin: 0 0 4px;
  font-size: 19px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.submodule h2 .icon {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--card-accent, var(--brand));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  flex-shrink: 0;
}
.submodule .tech {
  font-size: 12.5px;
  color: var(--text-muted);
  margin-bottom: 12px;
  font-style: italic;
}
.feature-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 8px 16px;
}
.feature-list li {
  font-size: 13.5px;
  padding-left: 18px;
  position: relative;
  color: var(--text);
}
.feature-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--card-accent, var(--brand));
}

.example-box {
  margin-top: 20px;
  background: var(--surface-alt);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
}
.example-box .label {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--card-accent, var(--brand));
  margin-bottom: 6px;
}
.example-box p { margin: 0; font-size: 13.5px; color: var(--text); }

/* ---------- Foundation / principles (home) ---------- */

.foundation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 12px;
}
.foundation-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
}
.foundation-item .icon { font-size: 18px; margin-bottom: 8px; }
.foundation-item h4 { margin: 0 0 4px; font-size: 14px; }
.foundation-item p { margin: 0; font-size: 12.5px; color: var(--text-muted); }

.principles-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 10px;
}
.principles-list li {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
  font-size: 13.5px;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: var(--shadow);
}
.principles-list li::before {
  content: "\2713";
  color: #fff;
  background: var(--accent-green);
  width: 20px;
  height: 20px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  flex-shrink: 0;
}

/* ---------- Flow ---------- */

.flow-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
}
.flow-step {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  background: var(--surface-alt);
  padding: 8px 12px;
  border-radius: 999px;
}
.flow-arrow { color: var(--text-muted); font-size: 14px; }

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}
.tag-row .tag {
  font-size: 11.5px;
  font-weight: 600;
  background: var(--surface-alt);
  color: var(--text-muted);
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: 999px;
}

/* ---------- Legend ---------- */

.legend-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  font-size: 13px;
  color: var(--text-muted);
}
.legend-list li { display: flex; align-items: center; gap: 8px; }
.legend-line { width: 28px; height: 0; border-top: 2px solid var(--text-muted); display: inline-block; }
.legend-line.dashed { border-top-style: dashed; }
.legend-line.dotted { border-top-style: dotted; }

/* ---------- Footer ---------- */

code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.9em;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 5px;
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 20px;
  text-align: center;
  font-size: 12.5px;
  color: var(--text-muted);
}