/* Horizon: a documentation theme.
 *
 * The future as the 1990s pictured it, taken at its word: clear skies,
 * engineered surfaces, a sunrise on the horizon. Matte colour, plain
 * geometry, nothing glowing. One file, no build step; a project changes
 * its look by overriding the custom properties in the first block.
 */

:root {
  --font-display: "Michroma", "Eurostile", "Microgramma", "Arial Black", sans-serif;
  --font-head: "Jost", "Futura", "Century Gothic", "Avenir Next", sans-serif;
  --font-body: "IBM Plex Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  /* The palette: sky, orbit teal, sunrise. */
  --sky-950: #0a1631;
  --sky-900: #0f2147;
  --sky-800: #17336a;
  --sky-600: #2558a0;
  --sky-300: #9cc0e6;
  --sky-100: #e3eef9;
  --teal-700: #08656d;
  --teal-600: #0b7a83;
  --teal-300: #7fd0d3;
  --teal-100: #dff3f3;
  --sun-600: #d9701c;
  --sun-500: #ef8a2b;
  --sun-300: #f6b44c;
  --sun-100: #fdf0dc;
  --rose-600: #b8434b;
  --rose-100: #f9e3e3;

  /* Surfaces and ink, daylight. */
  --paper: #f4f2ec;
  --grid: rgba(23, 51, 106, 0.055);
  --panel: #ffffff;
  --panel-2: #f8f9fb;
  --ink: #15213b;
  --ink-2: #44526e;
  --ink-3: #6d7a93;
  --rule: #d5dbe5;
  --rule-strong: #b9c3d3;
  --link: #1d5ca6;
  --link-hover: var(--teal-700);
  --accent: var(--teal-600);
  --mark: var(--sun-500);
  --code-bg: #0f1d39;
  --code-ink: #e4ebf6;
  --code-dim: #8494b1;
  --inline-code-bg: #e9eff7;
  --inline-code-ink: #173a6b;
  --shadow: 0 1px 0 rgba(255, 255, 255, 0.9) inset, 0 1px 2px rgba(15, 33, 71, 0.06),
    0 8px 24px -12px rgba(15, 33, 71, 0.18);

  --radius: 6px;
  --measure: 46rem;
  --sidebar: 15.5rem;
  --toc: 13rem;
  color-scheme: light;
}

/* Night shift: the same sky after sunset. */
:root[data-theme="dark"] {
  --paper: #0a1428;
  --grid: rgba(156, 192, 230, 0.05);
  --panel: #101d38;
  --panel-2: #0d1931;
  --ink: #dde6f3;
  --ink-2: #a9b6cc;
  --ink-3: #8090ab;
  --rule: #233559;
  --rule-strong: #2f4673;
  --link: #8cc0f2;
  --link-hover: var(--teal-300);
  --accent: #3fb6bc;
  --mark: #f39a45;
  --code-bg: #071022;
  --code-ink: #dfe7f4;
  --code-dim: #7d8da9;
  --inline-code-bg: #172a4d;
  --inline-code-ink: #cfe0f5;
  --teal-100: #0f2f38;
  --sun-100: #33240f;
  --rose-100: #3a1a20;
  --sky-100: #13284a;
  --shadow: 0 1px 0 rgba(255, 255, 255, 0.04) inset, 0 10px 28px -14px rgba(0, 0, 0, 0.6);
  color-scheme: dark;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0a1428;
    --grid: rgba(156, 192, 230, 0.05);
    --panel: #101d38;
    --panel-2: #0d1931;
    --ink: #dde6f3;
    --ink-2: #a9b6cc;
    --ink-3: #8090ab;
    --rule: #233559;
    --rule-strong: #2f4673;
    --link: #8cc0f2;
    --link-hover: var(--teal-300);
    --accent: #3fb6bc;
    --mark: #f39a45;
    --code-bg: #071022;
    --code-ink: #dfe7f4;
    --code-dim: #7d8da9;
    --inline-code-bg: #172a4d;
    --inline-code-ink: #cfe0f5;
    --teal-100: #0f2f38;
    --sun-100: #33240f;
    --rose-100: #3a1a20;
    --sky-100: #13284a;
    --shadow: 0 1px 0 rgba(255, 255, 255, 0.04) inset, 0 10px 28px -14px rgba(0, 0, 0, 0.6);
    color-scheme: dark;
  }
}

/* ------------------------------------------------------------ base */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-top: 1.5rem;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--ink);
  background-color: var(--paper);
  /* Engineering paper. */
  background-image: linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 28px 28px;
  background-position: -1px -1px;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  text-decoration-color: color-mix(in srgb, currentColor 35%, transparent);
}

a:hover {
  color: var(--link-hover);
  text-decoration-color: currentColor;
}

:focus-visible {
  outline: 2px solid var(--mark);
  outline-offset: 2px;
  border-radius: 2px;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0.5rem;
  z-index: 10;
  padding: 0.5rem 0.9rem;
  background: var(--panel);
  color: var(--ink);
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
}

.skip:focus {
  left: 0.75rem;
}

/* ------------------------------------------------------------ masthead */

.masthead {
  position: relative;
  color: #eaf1fb;
  background: radial-gradient(120% 140% at 50% 118%, rgba(246, 180, 76, 0.42) 0%,
      rgba(239, 138, 43, 0.16) 26%, transparent 52%),
    linear-gradient(180deg, var(--sky-950) 0%, var(--sky-900) 45%, var(--sky-800) 82%,
      #2a5a98 100%);
}

.masthead-bar {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  max-width: 88rem;
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: #f4f8fd;
  text-decoration: none;
}

.brand:hover {
  color: #ffffff;
}

.brand img {
  width: 34px;
  height: 34px;
  display: block;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 1.02rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.brand-tag {
  display: none;
  padding-left: 0.9rem;
  margin-left: 0.2rem;
  border-left: 1px solid rgba(255, 255, 255, 0.22);
  color: #b9cbe6;
  font-size: 0.86rem;
}

@media (min-width: 62rem) {
  .brand-tag {
    display: inline;
  }
}

.topnav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: auto;
}

.topnav a,
.theme-toggle {
  font-family: var(--font-head);
  font-size: 0.95rem;
  font-weight: 500;
  color: #d6e3f5;
  text-decoration: none;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  border: 1px solid transparent;
  background: none;
  cursor: pointer;
  line-height: 1.3;
}

.topnav a:hover,
.theme-toggle:hover {
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.28);
  background: rgba(255, 255, 255, 0.06);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.theme-toggle svg {
  width: 1rem;
  height: 1rem;
}

/* The horizon: three stripes, as on an airliner's flank. */
.horizon {
  height: 9px;
  background: linear-gradient(180deg, var(--sun-500) 0 4px, transparent 4px 5px,
      var(--sun-300) 5px 7px, transparent 7px 8px, var(--teal-600) 8px 9px);
}

/* ------------------------------------------------------------ hero */

.hero {
  max-width: 88rem;
  margin: 0 auto;
  padding: 3.2rem 1.5rem 3.6rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
  align-items: center;
}

@media (min-width: 60rem) {
  .hero {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
    padding: 4.2rem 2rem 4.6rem;
  }
}

.hero-eyebrow {
  font-family: var(--font-display);
  font-size: 0.72rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--sun-300);
  margin: 0 0 1rem;
}

.hero h1 {
  font-family: var(--font-head);
  font-weight: 500;
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  line-height: 1.06;
  letter-spacing: -0.01em;
  margin: 0 0 1.1rem;
  color: #ffffff;
}

.hero-lede {
  font-size: 1.16rem;
  line-height: 1.6;
  color: #c9d8ee;
  max-width: 38rem;
  margin: 0 0 1.8rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-head);
  font-weight: 500;
  font-size: 1rem;
  padding: 0.62rem 1.25rem;
  border-radius: 999px;
  text-decoration: none;
  border: 1px solid transparent;
  transition: background 120ms ease, border-color 120ms ease;
}

.btn.primary {
  color: #1a1206;
  background: linear-gradient(180deg, #f8bd5e 0%, var(--sun-500) 100%);
  border-color: #c96a17;
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.45) inset, 0 6px 16px -8px rgba(239, 138, 43, 0.8);
}

.btn.primary:hover {
  color: #1a1206;
  background: linear-gradient(180deg, #fac977 0%, #f2963d 100%);
}

.btn.secondary {
  color: #eaf1fb;
  border-color: rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.06);
}

.btn.secondary:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.55);
}

.hero-art {
  display: none;
}

@media (min-width: 60rem) {
  .hero-art {
    display: block;
  }
}

.hero-art svg {
  width: 100%;
  max-width: 26rem;
  height: auto;
  margin-left: auto;
  display: block;
}

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

.shell {
  max-width: 88rem;
  margin: 0 auto;
  padding: 1.75rem 1.5rem 3rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.75rem;
  align-items: start;
}

@media (min-width: 56rem) {
  .shell {
    grid-template-columns: var(--sidebar) minmax(0, 1fr);
  }
}

@media (min-width: 80rem) {
  .shell.with-toc {
    grid-template-columns: var(--sidebar) minmax(0, 1fr) var(--toc);
  }
}

/* ------------------------------------------------------------ sidebar */

.sidebar {
  font-size: 0.94rem;
}

.sidebar details {
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.sidebar summary {
  font-family: var(--font-display);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-2);
  padding: 0.8rem 1rem;
  cursor: pointer;
  list-style: none;
}

.sidebar summary::-webkit-details-marker {
  display: none;
}

.sidebar summary::after {
  content: "+";
  float: right;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1;
}

.sidebar details[open] summary::after {
  content: "−";
}

.sidebar .nav-inner {
  padding: 0 0.6rem 0.8rem;
}

@media (min-width: 56rem) {
  .sidebar {
    position: sticky;
    top: 1.25rem;
    max-height: calc(100vh - 2.5rem);
    overflow-y: auto;
  }

  .sidebar summary {
    display: none;
  }

  .sidebar .nav-inner {
    padding: 0.9rem 0.6rem;
  }
}

.nav-group + .nav-group {
  margin-top: 1rem;
}

.nav-label {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.62rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--teal-100);
  border-radius: 999px;
  padding: 0.22rem 0.7rem 0.2rem;
  margin: 0 0 0.35rem 0.35rem;
}

.nav-group ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-group a {
  display: block;
  padding: 0.3rem 0.75rem 0.3rem 0.95rem;
  border-left: 3px solid transparent;
  border-radius: 0 4px 4px 0;
  color: var(--ink-2);
  text-decoration: none;
  line-height: 1.4;
}

.nav-group a:hover {
  color: var(--ink);
  background: var(--panel-2);
}

.nav-group a[aria-current="page"] {
  color: var(--ink);
  font-weight: 600;
  border-left-color: var(--mark);
  background: linear-gradient(90deg, var(--sun-100), transparent);
}

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

.page {
  min-width: 0;
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2rem 1.4rem 2.4rem;
}

@media (min-width: 40rem) {
  .page {
    padding: 2.6rem 3rem 3rem;
  }
}

.page > * {
  max-width: var(--measure);
}

.page > .wide,
.page > .cards,
.page > .stack,
.page > div.sourceCode,
.page > pre,
.page > table,
.page > .table-wrap {
  max-width: 100%;
}

.eyebrow {
  font-family: var(--font-display);
  font-size: 0.68rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 0.6rem;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-head);
  color: var(--ink);
  line-height: 1.2;
  text-wrap: balance;
}

.page h1.title {
  font-size: clamp(2rem, 3.6vw, 2.6rem);
  font-weight: 500;
  letter-spacing: -0.01em;
  margin: 0 0 0.75rem;
}

.lede {
  font-size: 1.14rem;
  color: var(--ink-2);
  margin: 0 0 2rem;
}

.page h2 {
  font-size: 1.6rem;
  font-weight: 500;
  margin: 2.6rem 0 0.9rem;
  padding-top: 0.2rem;
}

.page h2::before {
  content: "";
  display: block;
  width: 2.6rem;
  height: 4px;
  margin-bottom: 0.75rem;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--sun-500) 0 60%, var(--sun-300) 60% 80%,
      var(--teal-600) 80%);
}

.page h3 {
  font-size: 1.22rem;
  font-weight: 600;
  margin: 2rem 0 0.6rem;
}

.page h4 {
  font-size: 1.02rem;
  font-weight: 600;
  margin: 1.5rem 0 0.4rem;
}

.page :is(h2, h3, h4) a.anchor {
  margin-left: 0.4rem;
  color: var(--ink-3);
  text-decoration: none;
  opacity: 0;
  font-weight: 400;
}

.page :is(h2, h3, h4):hover a.anchor {
  opacity: 1;
}

p,
ul,
ol,
dl {
  margin: 0 0 1rem;
}

li + li {
  margin-top: 0.25rem;
}

li > ul,
li > ol {
  margin-top: 0.25rem;
  margin-bottom: 0;
}

strong {
  font-weight: 600;
}

hr {
  border: 0;
  height: 1px;
  background: var(--rule);
  margin: 2.5rem 0;
}

dt {
  font-weight: 600;
  margin-top: 0.8rem;
}

dd {
  margin: 0.2rem 0 0 1.25rem;
  color: var(--ink-2);
}

blockquote {
  margin: 1.25rem 0;
  padding: 0.2rem 1.25rem;
  border-left: 3px solid var(--rule-strong);
  color: var(--ink-2);
}

kbd {
  font-family: var(--font-mono);
  font-size: 0.82em;
  padding: 0.05rem 0.4rem;
  border: 1px solid var(--rule-strong);
  border-bottom-width: 2px;
  border-radius: 4px;
  background: var(--panel-2);
  color: var(--ink);
}

/* ------------------------------------------------------------ code */

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
}

:not(pre) > code {
  padding: 0.1rem 0.36rem;
  border-radius: 4px;
  background: var(--inline-code-bg);
  color: var(--inline-code-ink);
  overflow-wrap: anywhere;
}

pre {
  position: relative;
  margin: 1.25rem 0 1.5rem;
  padding: 1rem 1.2rem;
  overflow-x: auto;
  background: var(--code-bg);
  color: var(--code-ink);
  border-radius: var(--radius);
  border: 1px solid #1d2f55;
  border-top: 3px solid var(--teal-600);
  line-height: 1.55;
  font-size: 0.9rem;
  tab-size: 4;
}

div.sourceCode {
  margin: 1.25rem 0 1.5rem;
}

div.sourceCode pre {
  margin: 0;
}

pre[data-lang]::before {
  content: attr(data-lang);
  position: absolute;
  top: 0;
  right: 0;
  padding: 0.2rem 0.6rem 0.25rem;
  font-family: var(--font-display);
  font-size: 0.58rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #9fb3d4;
  background: rgba(255, 255, 255, 0.05);
  border-bottom-left-radius: 4px;
}

.copy {
  position: absolute;
  bottom: 0.45rem;
  right: 0.5rem;
  font-family: var(--font-head);
  font-size: 0.78rem;
  color: #b8c7df;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 999px;
  padding: 0.15rem 0.6rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity 120ms ease;
}

pre:hover .copy,
.copy:focus-visible {
  opacity: 1;
}

/* Pandoc's highlighter classes, recoloured for the night panel. */
code span.kw,
code span.cf,
code span.im {
  color: #7fd0d3;
}

code span.dt,
code span.bu {
  color: #9cc0e6;
}

code span.st,
code span.ss,
code span.ch,
code span.vs {
  color: #f6c87a;
}

code span.dv,
code span.bn,
code span.fl,
code span.cn {
  color: #f3a26b;
}

code span.co,
code span.do,
code span.cv,
code span.an,
code span.in {
  color: var(--code-dim);
  font-style: italic;
}

code span.fu,
code span.at {
  color: #c4d7f5;
}

code span.op,
code span.ot,
code span.va {
  color: #dfe7f4;
}

code span.er,
code span.al {
  color: #f08a8f;
}

/* ------------------------------------------------------------ tables */

.table-wrap {
  overflow-x: auto;
  margin: 1.25rem 0 1.5rem;
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 0.93rem;
  margin: 1.25rem 0 1.5rem;
}

.table-wrap table {
  margin: 0;
}

thead th {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-2);
  background: var(--sky-100);
  text-align: left;
  border-bottom: 2px solid var(--rule-strong);
}

th,
td {
  padding: 0.55rem 0.8rem;
  vertical-align: top;
  border-bottom: 1px solid var(--rule);
}

tbody tr:hover {
  background: var(--panel-2);
}

td code {
  white-space: nowrap;
}

/* ------------------------------------------------------------ callouts */

.note,
.tip,
.safety,
.agent,
.warning {
  position: relative;
  margin: 1.5rem 0;
  padding: 1.05rem 1.2rem 0.4rem 1.2rem;
  border: 1px solid var(--rule);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  background: var(--panel-2);
}

.note::before,
.tip::before,
.safety::before,
.agent::before,
.warning::before {
  display: block;
  font-family: var(--font-display);
  font-size: 0.6rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  margin-bottom: 0.45rem;
  color: var(--accent);
}

.note::before {
  content: "Note";
}

.tip::before {
  content: "Tip";
}

.tip {
  border-left-color: var(--sky-600);
  background: var(--sky-100);
}

.tip::before {
  color: var(--sky-600);
}

.safety {
  border-left-color: var(--sun-500);
  background: var(--sun-100);
}

.safety::before {
  content: "Promise";
  color: var(--sun-600);
}

.warning {
  border-left-color: var(--rose-600);
  background: var(--rose-100);
}

.warning::before {
  content: "Caution";
  color: var(--rose-600);
}

.agent {
  border-left-color: var(--teal-600);
  background: var(--teal-100);
}

.agent::before {
  content: "For agents";
}

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

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14.5rem, 1fr));
  gap: 1rem;
  margin: 1.5rem 0 2rem;
}

.card {
  position: relative;
  padding: 1.2rem 1.2rem 0.6rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--panel) 0%, var(--panel-2) 100%);
  box-shadow: var(--shadow);
}

.card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  border-radius: var(--radius) var(--radius) 0 0;
  background: linear-gradient(90deg, var(--teal-600), var(--sky-600));
}

.card:nth-child(3n + 2)::before {
  background: linear-gradient(90deg, var(--sun-500), var(--sun-300));
}

.card:nth-child(3n + 3)::before {
  background: linear-gradient(90deg, var(--sky-600), var(--sky-300));
}

.card h3,
.card h4 {
  margin: 0.2rem 0 0.5rem;
  font-size: 1.12rem;
  font-weight: 600;
}

.card p {
  color: var(--ink-2);
  font-size: 0.96rem;
}

.card .label {
  display: block;
  font-family: var(--font-display);
  font-size: 0.58rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 0;
}

/* ------------------------------------------------------------ stack diagram */

.stack {
  display: grid;
  gap: 0.6rem;
  margin: 1.5rem 0 2rem;
  font-size: 0.93rem;
}

.stack .tier {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
  gap: 0.6rem;
}

.stack .box {
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  background: var(--panel);
  text-align: center;
  line-height: 1.35;
}

.stack .box .small {
  display: block;
  color: var(--ink-3);
  font-size: 0.82rem;
  margin-top: 0.2rem;
}

.stack .box.daemon {
  background: linear-gradient(180deg, var(--sky-900), var(--sky-800));
  color: #eaf1fb;
  border-color: var(--sky-800);
}

.stack .box.daemon .small {
  color: #a8bddd;
}

.stack .box.socket {
  background: var(--teal-100);
  border-color: color-mix(in srgb, var(--teal-600) 40%, transparent);
}

.stack .box.store {
  background: var(--sun-100);
  border-color: color-mix(in srgb, var(--sun-500) 45%, transparent);
}

.stack .wire {
  text-align: center;
  color: var(--ink-3);
  font-family: var(--font-display);
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

/* ------------------------------------------------------------ toc */

.toc {
  display: none;
  font-size: 0.88rem;
}

@media (min-width: 80rem) {
  .toc {
    display: block;
    position: sticky;
    top: 1.25rem;
    max-height: calc(100vh - 2.5rem);
    overflow-y: auto;
    padding-left: 0.25rem;
  }
}

.toc-title {
  font-family: var(--font-display);
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 0.4rem 0 0.6rem;
}

.toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.toc ul ul {
  padding-left: 0.85rem;
}

.toc li {
  margin: 0;
}

.toc a {
  display: block;
  padding: 0.2rem 0 0.2rem 0.7rem;
  border-left: 1px solid var(--rule);
  color: var(--ink-2);
  text-decoration: none;
  line-height: 1.35;
}

.toc a:hover {
  color: var(--ink);
  border-left-color: var(--mark);
}

.toc a.active {
  color: var(--ink);
  border-left: 2px solid var(--mark);
}

/* ------------------------------------------------------------ page foot */

.page-foot {
  margin-top: 3rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--rule);
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  font-size: 0.88rem;
  color: var(--ink-3);
}

.page-foot a {
  color: var(--ink-2);
}

.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 2.5rem;
}

.pager a {
  display: block;
  padding: 0.8rem 1rem;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--ink);
  background: var(--panel-2);
}

.pager a:hover {
  border-color: var(--accent);
}

.pager span {
  display: block;
  font-family: var(--font-display);
  font-size: 0.58rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 0.2rem;
}

.pager .next {
  text-align: right;
  grid-column: 2;
}

/* ------------------------------------------------------------ site foot */

.site-foot {
  margin-top: 1rem;
  color: #b9cbe6;
  background: var(--sky-950);
}

.site-foot-inner {
  max-width: 88rem;
  margin: 0 auto;
  padding: 1.6rem 1.5rem 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 2rem;
  align-items: center;
  justify-content: space-between;
  font-size: 0.88rem;
}

.site-foot a {
  color: #dbe7f7;
}

.site-foot .made {
  font-family: var(--font-display);
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #8ea6c9;
}

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

@media print {
  body {
    background: none;
  }

  .masthead,
  .sidebar,
  .toc,
  .site-foot,
  .copy,
  .pager {
    display: none;
  }

  .shell {
    display: block;
    padding: 0;
  }

  .page {
    border: 0;
    box-shadow: none;
    padding: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}

/* ------------------------------------------------------------ odds and ends */

.page > :first-child,
.page > .eyebrow + h1.title {
  margin-top: 0;
}

.stack > p {
  margin: 0;
  text-align: center;
}

/* Narrow screens: the contents menu does the navigating. */
@media (max-width: 40rem) {
  .masthead-bar {
    padding: 0.75rem 1rem;
  }

  .topnav a {
    display: none;
  }

  .shell {
    padding: 1.25rem 0.75rem 2rem;
  }
}