/* Peios Learn — front page.
   Light theme tokens on :root; dark redefines them under prefers-color-scheme.
   Product cards carry a per-card --pc (the product's hex color); tiles and
   hover accents derive their tints from it with color-mix, so one hex adapts
   to both themes. */

@font-face {
  font-family: "Inter";
  src: url("/assets/fonts/InterVariable.woff2") format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Space Grotesk";
  src: url("/assets/fonts/SpaceGroteskVariable.woff2") format("woff2");
  font-weight: 300 700;
  font-style: normal;
  font-display: swap;
}

/* Theme tokens. Three states: :root is light; data-theme="dark" (the
   header toggle) wins outright; the system preference applies only when
   the toggle hasn't pinned light. The two dark blocks below must stay
   identical — CSS offers no way to share them. */
:root {
  color-scheme: light;
  --bg: #f6f7f9;
  --surface: rgba(255, 255, 255, 0.72);
  --text: #15171c;
  --text-muted: #5c6470;
  --border: rgba(21, 23, 28, 0.09);
  --border-strong: rgba(21, 23, 28, 0.18);
  --accent: #635bff;
  --glow-mix: 10%;
  --glow: color-mix(in srgb, var(--accent) var(--glow-mix), transparent);
  --headline: linear-gradient(180deg, #15171c 55%, #5c6470);
  --tile-mix: 10%;
  --tile-fg-mix: 62%;
  --card-shadow: 0 8px 24px rgba(21, 23, 28, 0.07);
  --menu-bg: #ffffff;
  --code-comment: #6a737d;
  --code-keyword: #cf222e;
  --code-string: #0a3069;
  --code-constant: #0550ae;
  --code-function: #8250df;
  --code-type: #953800;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0a0c10;
  --surface: rgba(255, 255, 255, 0.028);
  --text: #eceef2;
  --text-muted: #99a3b3;
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --accent: #8b7bff;
  --glow-mix: 13%;
  --headline: linear-gradient(180deg, #ffffff 55%, #9aa4b4);
  --tile-mix: 15%;
  --tile-fg-mix: 80%;
  --card-shadow: 0 8px 28px rgba(0, 0, 0, 0.35);
  --menu-bg: #12151b;
  --code-comment: #8b949e;
  --code-keyword: #ff7b72;
  --code-string: #a5d6ff;
  --code-constant: #79c0ff;
  --code-function: #d2a8ff;
  --code-type: #ffa657;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #0a0c10;
    --surface: rgba(255, 255, 255, 0.028);
    --text: #eceef2;
    --text-muted: #99a3b3;
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.16);
    --accent: #8b7bff;
    --glow-mix: 13%;
    --headline: linear-gradient(180deg, #ffffff 55%, #9aa4b4);
    --tile-mix: 15%;
    --tile-fg-mix: 80%;
    --card-shadow: 0 8px 28px rgba(0, 0, 0, 0.35);
    --menu-bg: #12151b;
  --code-comment: #8b949e;
  --code-keyword: #ff7b72;
  --code-string: #a5d6ff;
  --code-constant: #79c0ff;
  --code-function: #d2a8ff;
  --code-type: #ffa657;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  font-optical-sizing: auto;
  -webkit-font-smoothing: antialiased;
  line-height: 1.55;
}

/* Ambient glow behind the hero. */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(42rem 26rem at 50% -6rem, var(--glow), transparent 70%);
}

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

h1, h2, h3 { line-height: 1.15; margin: 0; }

/* Display face for brand and titles; body stays in Inter. */
.wordmark, .hero h1, .card h3 {
  font-family: "Space Grotesk", "Inter", system-ui, sans-serif;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.6rem 1.5rem;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 72%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  padding: 0.35rem;
  margin: -0.35rem 0;
  color: var(--text-muted);
  background: none;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}
.menu-toggle:hover { color: var(--text); }

.wordmark {
  font-size: 1.02rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  color: var(--text);
  white-space: nowrap;
}
.wordmark span { color: var(--accent); }
.wordmark:hover { text-decoration: none; }

/* The drawer's own wordmark: only exists visually while the sidebar is
   a drawer (it covers the header's). */
.drawer-wordmark { display: none; }

.site-nav {
  display: flex;
  gap: 1.2rem;
  flex: 1;
}

/* Product switcher — a <details> so it works without JavaScript. */

.nav-dropdown { position: relative; }

.nav-dropdown summary {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  list-style: none;
  color: var(--text-muted);
  font-size: 0.9rem;
  cursor: pointer;
  user-select: none;
  transition: color 0.15s ease;
}
.nav-dropdown summary::-webkit-details-marker { display: none; }
.nav-dropdown summary:hover,
.nav-dropdown[open] summary { color: var(--text); }

.nav-dropdown summary::after {
  content: "";
  width: 0.4em;
  height: 0.4em;
  margin-top: -0.2em;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: rotate(45deg);
  transition: transform 0.15s ease;
}
.nav-dropdown[open] summary::after {
  transform: rotate(225deg);
  margin-top: 0.2em;
}

.menu {
  position: absolute;
  top: calc(100% + 0.75rem);
  left: -0.6rem;
  z-index: 20;
  display: grid;
  grid-template-columns: repeat(2, minmax(11rem, max-content));
  gap: 0.15rem 1rem;
  padding: 0.45rem;
  background: var(--menu-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--card-shadow);
}

.menu-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.45rem 0.6rem;
  border-radius: 8px;
  color: var(--text);
  font-size: 0.88rem;
  white-space: nowrap;
}
.menu-item:hover {
  background: color-mix(in srgb, var(--accent) 9%, transparent);
  text-decoration: none;
}

.tile-menu {
  flex: none;
  width: 1.6rem;
  height: 1.6rem;
  border-radius: 6px;
  font-size: 0.62rem;
  margin: 0;
}

/* ---- Search ------------------------------------------------------------- */

.search {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font: inherit;
  color: inherit;
  cursor: pointer;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  transition: border-color 0.15s ease;
}
.search:hover { border-color: var(--border-strong); }
.search:focus-visible {
  border-color: var(--accent);
  outline: 3px solid color-mix(in srgb, var(--accent) 25%, transparent);
}

.search-icon {
  display: none;
  flex: none;
  color: var(--text-muted);
}

/* Theme toggle: cycles system → light → dark; the state attribute picks
   which icon shows. */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
  padding: 0.42rem;
  color: var(--text-muted);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  cursor: pointer;
  transition: border-color 0.15s ease;
}
.theme-toggle:hover { border-color: var(--border-strong); color: var(--text); }
.theme-toggle:focus-visible {
  border-color: var(--accent);
  outline: 3px solid color-mix(in srgb, var(--accent) 25%, transparent);
}
.theme-toggle svg { display: none; }
.theme-toggle[data-theme-state="system"] svg[data-theme-icon="system"],
.theme-toggle[data-theme-state="light"] svg[data-theme-icon="light"],
.theme-toggle[data-theme-state="dark"] svg[data-theme-icon="dark"] { display: block; }

.search-placeholder {
  flex: 1;
  min-width: 0;
  text-align: left;
  color: var(--text-muted);
}

.search kbd {
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.68rem;
  color: var(--text-muted);
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  padding: 0.1rem 0.35rem;
  white-space: nowrap;
}

.search-small {
  width: 13.5rem;
  padding: 0.32rem 0.6rem 0.32rem 0.9rem;
  font-size: 0.88rem;
}

.search-hero {
  width: 100%;
  max-width: 33rem;
  margin: 2rem auto 0;
  padding: 0.65rem 0.8rem 0.65rem 1.15rem;
  font-size: 1rem;
  box-shadow: var(--card-shadow);
}

/* The dimmed page behind the open drawer. Inert until opened — and the
   toggle only shows on small screens, so it never activates on desktop. */
.drawer-overlay {
  position: fixed;
  inset: 0;
  z-index: 25;
  background: rgba(10, 12, 16, 0.45);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}
body.drawer-open .drawer-overlay {
  opacity: 1;
  pointer-events: auto;
}
body.drawer-open { overflow: hidden; }

/* ---- Search modal --------------------------------------------------------- */

.search-modal {
  width: min(38rem, calc(100vw - 2rem));
  margin: 10vh auto auto;
  padding: 0;
  border: 1px solid var(--border-strong);
  border-radius: 14px;
  background: var(--menu-bg);
  color: var(--text);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.35);
}
.search-modal::backdrop {
  background: rgba(10, 12, 16, 0.45);
}

.search-panel {
  display: flex;
  flex-direction: column;
  max-height: min(28rem, 70vh);
}

.search-box {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.35rem 0.9rem;
  border-bottom: 1px solid var(--border);
}
.search-box input {
  flex: 1;
  min-width: 0;
  padding: 0.7rem 0;
  font: inherit;
  font-size: 1rem;
  color: var(--text);
  background: none;
  border: none;
  outline: none;
}
.search-box input::placeholder { color: var(--text-muted); }

.search-close {
  padding: 0;
  font: inherit;
  background: none;
  border: none;
  cursor: pointer;
}
.search-close kbd {
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.68rem;
  color: var(--text-muted);
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  padding: 0.1rem 0.35rem;
}

.search-results {
  list-style: none;
  margin: 0;
  padding: 0.4rem;
  overflow-y: auto;
}
.search-results:empty { padding: 0; }
.search-results a {
  display: block;
  padding: 0.55rem 0.7rem;
  border-radius: 10px;
  color: inherit;
}
.search-results a:hover { text-decoration: none; }
.search-results li[aria-selected="true"] a {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
}

.result-title {
  margin: 0;
  font-size: 0.92rem;
  font-weight: 600;
}
.result-crumbs {
  margin: 0.1rem 0 0;
  font-size: 0.74rem;
  color: var(--text-muted);
}
.result-excerpt {
  margin: 0.2rem 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.result-excerpt mark {
  background: none;
  color: color-mix(in srgb, var(--accent) 80%, var(--text));
  font-weight: 600;
}

.search-status {
  margin: 0;
  padding: 0.55rem 1.1rem 0.7rem;
  font-size: 0.78rem;
  color: var(--text-muted);
}
.search-status:empty { display: none; }

/* ---- Print pages (single-page unit views) --------------------------------- */

.print-page {
  max-width: 46rem;
  margin: 0 auto;
  padding: 2.25rem 1.5rem 4.5rem;
}

.print-header {
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}
.print-header h1 {
  font-family: "Space Grotesk", "Inter", system-ui, sans-serif;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0;
}
.print-note {
  margin: 0.8rem 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.print-article {
  padding-top: 2.5rem;
}
.print-article + .print-article {
  margin-top: 2.5rem;
  border-top: 1px solid var(--border);
}
.print-article > header h2 {
  font-family: "Space Grotesk", "Inter", system-ui, sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0;
}
.print-crumbs {
  margin: 0.25rem 0 0;
  font-size: 0.78rem;
  color: var(--text-muted);
}

@media print {
  .site-header, .site-footer, .search-modal, .print-note { display: none; }
}

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

.hero {
  position: relative;
  max-width: 48rem;
  margin: 0 auto;
  padding: 5.5rem 1.5rem 4rem;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 3.4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  background: var(--headline);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.lede {
  max-width: 38rem;
  margin: 1.1rem auto 0;
  font-size: 1.08rem;
  color: var(--text-muted);
}

/* ---- Product & anthology page heroes --------------------------------------- */

.tile-hero {
  width: 3.25rem;
  height: 3.25rem;
  border-radius: 12px;
  font-size: 1.15rem;
  margin-bottom: 1.1rem;
}

.crumb {
  display: inline-block;
  margin-bottom: 0.9rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.crumb:hover { color: var(--text); text-decoration: none; }

.hero-crumbs {
  justify-content: center;
  margin-bottom: 0.9rem;
}

.anthology-grid {
  grid-template-columns: repeat(auto-fill, minmax(18rem, 1fr));
}

/* ---- Topic cards --------------------------------------------------------- */

.topic-card h3 a { color: inherit; }
.topic-card h3 a:hover {
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  text-decoration: none;
}

.article-list {
  list-style: none;
  margin: 0.8rem 0 0;
  padding: 0;
}
.article-list li {
  border-top: 1px solid var(--border);
  padding: 0.32rem 0;
  font-size: 0.88rem;
}
.article-list a { color: var(--text-muted); }
.article-list a:hover {
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  text-decoration: none;
}

.see-all {
  display: inline-block;
  margin-top: 0.55rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
}
.see-all::after { content: " \2192"; }
.see-all:hover {
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  text-decoration: none;
}

/* ---- Product cards ------------------------------------------------------ */

.products,
.anthologies {
  max-width: 72rem;
  margin: 0 auto;
  padding: 0 1.5rem 4.5rem;
}

.products h2,
.anthologies h2 {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 1.2rem;
}

.shelf-title {
  font-family: "Space Grotesk", "Inter", system-ui, sans-serif;
  font-size: 1.15rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  margin: 2.2rem 0 1rem;
}

.anthologies .card-grid:not(:last-child) { margin-bottom: 1.5rem; }

.card-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(15.5rem, 1fr));
  gap: 1rem;
}

.card {
  display: block;
  height: 100%;
  padding: 1.2rem 1.3rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  color: inherit;
  transition: border-color 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
}
.card:hover {
  text-decoration: none;
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--pc) 55%, transparent);
  box-shadow: var(--card-shadow);
}

.tile {
  display: inline-grid;
  place-items: center;
  width: 2.15rem;
  height: 2.15rem;
  border-radius: 9px;
  background: color-mix(in srgb, var(--pc) var(--tile-mix), transparent);
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  font-size: 0.8rem;
  font-weight: 650;
  margin-bottom: 0.75rem;
}

.card h3 {
  font-size: 1rem;
  font-weight: 620;
  letter-spacing: -0.01em;
}
.card p {
  margin: 0.4rem 0 0;
  font-size: 0.87rem;
  color: var(--text-muted);
}

/* ---- Books ---------------------------------------------------------------- */

.book-pill {
  display: inline-block;
  margin-bottom: 0.6rem;
  padding: 0.16rem 0.55rem;
  border-radius: 999px;
  font-size: 0.66rem;
  font-weight: 650;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  background: color-mix(in srgb, var(--pc) var(--tile-mix), transparent);
  border: 1px solid color-mix(in srgb, var(--pc) 25%, transparent);
}

.book-short {
  margin: 0 0 0.5rem;
  font-size: 0.78rem;
  font-weight: 650;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
}

.book-lede {
  margin: 0.75rem 0 0;
  font-size: 1.05rem;
  color: var(--text-muted);
}

/* Section numbers come from the authored NN-- orders ("2.1"). */
.section-number {
  display: inline-block;
  min-width: 2.2rem;
  padding-right: 0.45rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  font-weight: 400;
}

/* ---- Article page ------------------------------------------------------- */

.article-layout {
  display: grid;
  grid-template-columns: 15rem minmax(0, 1fr) 13rem;
  gap: 2.75rem;
  max-width: 82rem;
  margin: 0 auto;
  padding: 2.25rem 1.5rem 4.5rem;
}

.sidebar,
.toc {
  position: sticky;
  top: 4.25rem;
  align-self: start;
  max-height: calc(100vh - 6rem);
  overflow-y: auto;
  font-size: 0.88rem;
}

.sidebar-topic {
  margin: 0 0 0.4rem;
  font-weight: 600;
}
.sidebar-topic a { color: var(--text); }
.sidebar-topic a:hover {
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  text-decoration: none;
}

.sidebar-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--border);
}
.sidebar-list a {
  display: block;
  padding: 0.28rem 0.85rem;
  color: var(--text-muted);
  border-left: 2px solid transparent;
  margin-left: -1px;
}
.sidebar-list a:hover {
  color: var(--text);
  text-decoration: none;
}
.sidebar-list a.current {
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  border-left-color: color-mix(in srgb, var(--pc) 70%, transparent);
  font-weight: 550;
}

/* Collapsing sidebar groups: book chapters and topic subfolders are
   <details>, open along the trail to the current page. Chapter labels
   are bold; subfolder labels look like any other page link. */
.sidebar-chapter summary,
.sidebar-folder summary {
  list-style: none;
  position: relative;
  cursor: pointer;
}
.sidebar-chapter summary::-webkit-details-marker,
.sidebar-folder summary::-webkit-details-marker { display: none; }
.sidebar-chapter summary::after,
.sidebar-folder summary::after {
  content: "";
  position: absolute;
  right: 0.55rem;
  top: 50%;
  width: 0.32rem;
  height: 0.32rem;
  border-right: 1.5px solid var(--text-muted);
  border-bottom: 1.5px solid var(--text-muted);
  transform: translateY(-50%) rotate(-45deg);
  transition: transform 0.15s ease;
}
.sidebar-chapter details[open] > summary::after,
.sidebar-folder details[open] > summary::after {
  transform: translateY(-65%) rotate(45deg);
}
/* The label link stops short of the chevron strip: clicking the title
   navigates, clicking the strip (part of the <summary>) expands the
   group without leaving the page. */
.sidebar-chapter summary a,
.sidebar-folder summary a {
  margin-right: 2.2rem;
  padding-right: 0;
}
.sidebar-chapter summary:hover::after,
.sidebar-folder summary:hover::after {
  border-color: var(--text);
}
.sidebar-chapter summary a {
  color: var(--text);
  font-weight: 600;
}
.sidebar-list .sidebar-list {
  margin-left: 0.85rem;
}
.sidebar-list .section-number {
  min-width: 1.9rem;
  padding-right: 0.35rem;
}

/* Appendix rows carry a small "APPENDIX A" eyebrow above the title
   instead of a number column. */
.sidebar-list .appendix-number {
  display: block;
  font-size: 0.66rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-muted);
}

/* Heading numbers inside book articles are real text (searchable,
   copyable); mute them so titles stay the anchor of the line. */
.heading-number {
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.toc .section-number {
  min-width: 0;
  padding-right: 0.35rem;
}

.sidebar-toc {
  display: none;
  margin-top: 1.4rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--border);
}
.sidebar-toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--border);
}
.sidebar-toc a {
  display: block;
  padding: 0.28rem 0.85rem;
  color: var(--text-muted);
}
.sidebar-toc a:hover { color: var(--text); text-decoration: none; }
.sidebar-toc .toc-3 a { padding-left: 1.7rem; }
.sidebar-toc .section-number {
  display: inline-block;
  min-width: 0;
  padding-right: 0.35rem;
}

.toc-label {
  margin: 0 0 0.4rem;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--border);
}
.toc a {
  display: block;
  padding: 0.24rem 0.85rem;
  color: var(--text-muted);
  border-left: 2px solid transparent;
  margin-left: -1px;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.active {
  color: color-mix(in srgb, var(--pc) var(--tile-fg-mix), var(--text));
  border-left-color: color-mix(in srgb, var(--pc) 70%, transparent);
  font-weight: 550;
}
.toc .toc-3 a { padding-left: 1.7rem; }

.crumbs {
  display: flex;
  gap: 0.5rem;
  font-size: 0.84rem;
  color: var(--text-muted);
  margin-bottom: 1.2rem;
}
.crumbs a { color: var(--text-muted); }
.crumbs a:hover { color: var(--text); text-decoration: none; }

.article-body,
.print-article {
  line-height: 1.65;
  /* The reader's text-size choice scales the prose only, so the chrome
     never eats the screen the way browser zoom does. */
  font-size: calc(1rem * var(--reading-scale, 1));
}

.article-body h1,
.print-article h1 {
  font-family: "Space Grotesk", "Inter", system-ui, sans-serif;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 1.1rem;
}
.article-body h2,
.print-article h2 {
  font-size: 1.4rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  margin: 2.3rem 0 0.8rem;
}
.article-body h3,
.print-article h3 {
  font-size: 1.12rem;
  font-weight: 620;
  margin: 1.8rem 0 0.6rem;
}
.article-body p,
.print-article p { margin: 0.85rem 0; }
.article-body img,
.print-article img { max-width: 100%; height: auto; }

/* Related Content: the resolved `related:` list at the foot of a page. */
.article-body .related {
  margin-top: 3rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}
.article-body .related-label {
  margin: 0 0 0.6rem;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.article-body .related-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.article-body .related-list li { margin: 0.3rem 0; }
.article-body figure,
.print-article figure { margin: 1.4rem 0; }
.article-body figcaption,
.print-article figcaption {
  margin-top: 0.5rem;
  font-size: 0.84rem;
  color: var(--text-muted);
}

.article-body code,
.print-article code {
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.86em;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.08em 0.35em;
}
.article-body pre,
.print-article pre {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.2rem;
  overflow-x: auto;
  margin: 1.1rem 0;
}
.article-body pre code,
.print-article pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.85rem;
}
.article-body pre.mermaid,
.print-article pre.mermaid {
  display: flex;
  justify-content: center;
  background: none;
  border: none;
}

.table-scroll {
  overflow-x: auto;
  margin: 1.1rem 0;
}
.article-body table,
.print-article table {
  border-collapse: collapse;
  width: 100%;
  margin: 0;
  font-size: 0.92rem;
}
.article-body th,
.print-article th,
.article-body td,
.print-article td {
  text-align: left;
  padding: 0.5rem 0.8rem;
  border-bottom: 1px solid var(--border);
}
.article-body th,
.print-article th {
  font-weight: 600;
  border-bottom-color: var(--border-strong);
}

.article-body blockquote,
.print-article blockquote {
  margin: 1.1rem 0;
  padding: 0.1rem 0 0.1rem 1.1rem;
  border-left: 3px solid var(--border-strong);
  color: var(--text-muted);
}

/* Admonitions: `> [!NOTE]`-style asides, tinted by type via --adm. */

.admonition {
  margin: 1.1rem 0;
  padding: 0.8rem 1.15rem 0.9rem;
  border-left: 3px solid var(--adm);
  border-radius: 0 10px 10px 0;
  background: color-mix(in srgb, var(--adm) 7%, transparent);
}
.admonition-title {
  margin: 0;
  font-size: 0.76rem;
  font-weight: 650;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--adm) var(--tile-fg-mix), var(--text));
}
.admonition > p:not(.admonition-title) { margin: 0.4rem 0 0; }

.admonition-note { --adm: #3b82f6; }
.admonition-tip { --adm: #22c55e; }
.admonition-important { --adm: #a855f7; }
.admonition-warning { --adm: #eab308; }
.admonition-caution { --adm: #ef4444; }

@media (max-width: 1100px) {
  .article-layout { grid-template-columns: 15rem minmax(0, 1fr); }
  .toc { display: none; }
  .sidebar-toc { display: block; }
}

/* ≤800px: the sidebar becomes a slide-in drawer behind the header's
   menu button — same element, repositioned, so the tree (and its
   "On this page" section) needs no duplicate markup. */
@media (max-width: 800px) {
  .article-layout { grid-template-columns: minmax(0, 1fr); }
  .menu-toggle { display: flex; }
  .sidebar {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 30;
    width: min(19rem, 85vw);
    max-height: none;
    padding: 1.2rem 1.3rem 2.5rem;
    background: var(--bg);
    border-right: 1px solid var(--border);
    transform: translateX(-105%);
    transition: transform 0.2s ease;
  }
  body.drawer-open .sidebar { transform: none; }
  .drawer-wordmark {
    display: block;
    margin-bottom: 1rem;
    padding-bottom: 0.9rem;
    border-bottom: 1px solid var(--border);
  }
}

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

.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.6rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.site-footer p { margin: 0.2rem 0; }
.colophon { font-size: 0.76rem; opacity: 0.8; }

/* ---- Small screens ------------------------------------------------------ */

@media (max-width: 640px) {
  .site-header {
    gap: 0.9rem;
    padding: 0.6rem 1rem;
  }
  /* The search pill collapses to a bare magnifier icon. */
  .search-small {
    width: auto;
    padding: 0.42rem;
  }
  .search-small .search-placeholder,
  .search-small kbd { display: none; }
  .search-small .search-icon { display: block; }
  /* The product menu fits the screen as a single column. */
  .menu {
    grid-template-columns: 1fr;
    max-width: calc(100vw - 2rem);
    max-height: min(24rem, 70vh);
    overflow-y: auto;
  }
  /* Top-anchor the search modal: the on-screen keyboard takes the
     bottom half of a phone screen. */
  .search-modal { margin: 0.75rem auto auto; }
  .hero { padding-top: 3.5rem; }
}

@media (prefers-reduced-motion: reduce) {
  .sidebar, .drawer-overlay { transition: none; }
}

/* ---- Inline references & RFC keywords -------------------------------- */

/* RFC-2119 requirement keywords (MUST, SHOULD NOT, ...) stand out
   wherever prose states them, tinted by the surrounding product. */
.rfc-keyword {
  font-weight: 600;
  color: var(--pc, var(--accent));
}

/* ---- 404 ------------------------------------------------------------- */

.not-found {
  max-width: 34rem;
  margin: 0 auto;
  padding: 6rem 1.5rem 8rem;
  text-align: center;
}
.not-found-code {
  font-size: 4rem;
  font-weight: 700;
  color: var(--accent);
  margin: 0;
}
.not-found h1 {
  font-size: 1.4rem;
  margin: 0.5rem 0 1rem;
}
.not-found-hint {
  color: var(--text-muted);
  margin: 0 0 1.5rem;
}

/* ---- Header nav links & edit links ----------------------------------- */

/* Configured [[nav]] links sit beside the products menu on wide
   screens; on phones they fold into the products menu instead. */
.nav-link {
  align-self: center;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
}
.nav-link:hover { color: var(--text); }

.menu-links {
  display: none;
  border-top: 1px solid var(--border);
  margin-top: 0.4rem;
  padding-top: 0.4rem;
}

@media (max-width: 640px) {
  .nav-link { display: none; }
  .menu-links { display: block; }
}

.edit-page {
  margin-top: 2.5rem;
  font-size: 0.85rem;
}
.edit-page a {
  color: var(--text-muted);
  text-decoration: none;
}
.edit-page a:hover { color: var(--text); text-decoration: underline; }

/* ---- Code blocks: highlighting, copy button -------------------------- */

/* Highlighting is class-based (see highlight.rs), so code follows the
   reader's light/dark choice like everything else. Only these scope
   atoms are painted; the rest inherit, which keeps unknown languages
   and exotic grammars looking deliberate rather than half-coloured. */
.hl-comment { color: var(--code-comment); font-style: italic; }
.hl-string { color: var(--code-string); }
.hl-constant { color: var(--code-constant); }
.hl-keyword,
.hl-storage { color: var(--code-keyword); }
.hl-entity.hl-name.hl-function { color: var(--code-function); }
.hl-entity.hl-name.hl-type,
.hl-entity.hl-name.hl-class,
.hl-entity.hl-name.hl-struct,
.hl-entity.hl-name.hl-tag,
.hl-support.hl-type,
.hl-support.hl-class,
.hl-support.hl-function { color: var(--code-type); }
.hl-invalid { color: #cf222e; }

.code-block {
  position: relative;
  margin: 1.1rem 0;
}
.code-block pre { margin: 0; }

/* The copy button stays out of the way until the block is hovered or
   the button itself is focused — visible enough to find, quiet enough
   not to compete with the code. */
.copy-code {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  z-index: 1;
  padding: 0.25rem 0.55rem;
  font: inherit;
  font-size: 0.75rem;
  color: var(--text-muted);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.12s ease, color 0.12s ease;
}
.code-block:hover .copy-code,
.copy-code:focus-visible { opacity: 1; }
.copy-code:hover { color: var(--text); }
.copy-code[data-copied] { opacity: 1; color: var(--accent); }

@media (hover: none) {
  /* No hover to reveal it on touch devices. */
  .copy-code { opacity: 1; }
}

/* Nothing to copy on paper. */
@media print { .copy-code { display: none; } }

/* ---- Heading permalinks ---------------------------------------------- */

.heading-anchor {
  margin-left: 0.4em;
  color: var(--text-muted);
  text-decoration: none;
  opacity: 0;
  transition: opacity 0.12s ease;
}
h1:hover > .heading-anchor,
h2:hover > .heading-anchor,
h3:hover > .heading-anchor,
h4:hover > .heading-anchor,
h5:hover > .heading-anchor,
h6:hover > .heading-anchor,
.heading-anchor:focus-visible { opacity: 1; }
.heading-anchor:hover { color: var(--accent); }

/* ---- Tab groups ------------------------------------------------------ */

.tabs {
  margin: 1.2rem 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
}
.tab-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.15rem;
  padding: 0.3rem 0.3rem 0;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.tab-button {
  padding: 0.4rem 0.75rem;
  font: inherit;
  font-size: 0.85rem;
  color: var(--text-muted);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  border-radius: 6px 6px 0 0;
  cursor: pointer;
}
.tab-button:hover { color: var(--text); }
.tab-button[aria-selected="true"] {
  color: var(--pc, var(--accent));
  border-bottom-color: var(--pc, var(--accent));
}
.tab-panel { padding: 0.2rem 1rem 0.6rem; }
/* A code block filling a panel sits flush inside it. */
.tab-panel > .code-block:only-child { margin: 0.6rem 0; }

@media print {
  /* Paper can't click: every panel prints, labelled. */
  .tab-buttons { display: none; }
  .tab-panel[hidden] { display: block !important; }
  .tab-panel::before {
    content: attr(data-tab-label);
    display: block;
    font-weight: 600;
    font-size: 0.85rem;
    margin: 0.6rem 0 0.2rem;
  }
}

/* ---- Back to top ----------------------------------------------------- */

.back-to-top {
  position: fixed;
  right: 1.25rem;
  bottom: 1.25rem;
  z-index: 20;
  display: grid;
  place-items: center;
  width: 2.5rem;
  height: 2.5rem;
  color: var(--text-muted);
  background: var(--menu-bg);
  border: 1px solid var(--border);
  border-radius: 50%;
  box-shadow: var(--card-shadow);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.16s ease, visibility 0.16s ease, color 0.16s ease;
}
.back-to-top[data-visible] { opacity: 1; visibility: visible; }
.back-to-top:hover { color: var(--text); }
@media print { .back-to-top { display: none; } }

/* ---- Reading size controls ------------------------------------------- */

.reading-size {
  display: flex;
  align-items: baseline;
  gap: 0.1rem;
  margin-bottom: 1rem;
  padding-bottom: 0.8rem;
  border-bottom: 1px solid var(--border);
}
.reading-size button {
  padding: 0.1rem 0.4rem;
  font-family: inherit;
  color: var(--text-muted);
  background: none;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  line-height: 1;
}
.reading-size button:hover { color: var(--text); }
.reading-size button[aria-pressed="true"] { color: var(--pc, var(--accent)); }
.reading-size button:nth-child(1) { font-size: 0.75rem; }
.reading-size button:nth-child(2) { font-size: 0.92rem; }
.reading-size button:nth-child(3) { font-size: 1.1rem; }

/* ---- Search term highlighting ---------------------------------------- */

/* Arriving from a search result marks the terms that brought you here. */
.article-body mark.search-hit {
  background: color-mix(in srgb, var(--accent) 22%, transparent);
  color: inherit;
  border-radius: 3px;
  padding: 0 0.1em;
}
.article-body mark.search-hit:first-of-type {
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 35%, transparent);
}

/* ---- Article meta line & card meta ----------------------------------- */

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: -0.5rem 0 1.6rem;
  color: var(--text-muted);
  font-size: 0.82rem;
}
.meta-dot { opacity: 0.5; }

.card-meta {
  margin: 0.6rem 0 0;
  color: var(--text-muted);
  font-size: 0.78rem;
}

/* ---- Print-view link & pager ----------------------------------------- */

/* The crumbs row carries the single-page link on the far side. */
.crumbs { position: relative; }
.print-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  float: right;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.78rem;
}
.print-link:hover { color: var(--pc, var(--accent)); }
@media (max-width: 640px) {
  /* The label alone would crowd the crumbs; the icon still reads. */
  .print-link span { display: none; }
}

.pager {
  display: flex;
  gap: 0.75rem;
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}
.pager a {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  padding: 0.7rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  text-decoration: none;
  color: var(--text);
  transition: border-color 0.14s ease;
}
.pager a:hover { border-color: var(--pc, var(--accent)); }
.pager-next { text-align: right; }
.pager-label {
  color: var(--text-muted);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.pager-title { font-size: 0.9rem; font-weight: 550; }
@media print { .pager, .print-link { display: none; } }