/* Farrier documentation site.
 *
 * One stylesheet, no fonts fetched, no scripts. A documentation site that pulls a font from a third
 * party makes every reader's browser announce that they are reading it, which for a security document
 * is a slightly absurd thing to arrange. The system stack is also the fastest thing available.
 */

:root {
  color-scheme: light dark;

  --bg: #fbfaf8;
  --bg-raised: #ffffff;
  --bg-sunken: #f2efea;
  --ink: #23201c;
  --ink-soft: #5c554c;
  --ink-faint: #8a8177;
  --rule: #e3ded6;
  --accent: #9a5b2c;
  --accent-soft: #f4e9df;
  --bad: #a12d2d;
  --good: #2f6b3f;
  --warn: #8a6100;
  --sidebar: 19rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16150f;
    --bg-raised: #1e1c16;
    --bg-sunken: #100f0a;
    --ink: #ece7dd;
    --ink-soft: #b3aa9c;
    --ink-faint: #8a8177;
    --rule: #35312a;
    --accent: #e0a06a;
    --accent-soft: #2b2319;
    --bad: #e58b8b;
    --good: #8fc99f;
    --warn: #dbb45e;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
}

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
  z-index: 10;
  padding: 0.5rem 0.75rem;
  background: var(--accent);
  color: #fff;
  border-radius: 4px;
}

.shell {
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr);
  gap: 0;
  max-width: 78rem;
  margin: 0 auto;
}

/* Navigation */

.sidebar {
  border-right: 1px solid var(--rule);
  padding: 2rem 1.5rem 3rem;
  position: sticky;
  top: 0;
  align-self: start;
  max-height: 100vh;
  overflow-y: auto;
}

.brand {
  display: block;
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
  text-decoration: none;
}

.brand-sub {
  margin: 0.35rem 0 1.75rem;
  font-size: 0.83rem;
  line-height: 1.5;
  color: var(--ink-faint);
}

.sidebar ul {
  list-style: none;
  margin: 0 0 1.75rem;
  padding: 0;
}

.sidebar li { margin: 0 0 0.15rem; }

.sidebar li a {
  display: block;
  padding: 0.45rem 0.6rem;
  border-radius: 6px;
  text-decoration: none;
  color: var(--ink-soft);
}

.sidebar li a:hover { background: var(--bg-sunken); }

.sidebar li a[aria-current="page"] {
  background: var(--accent-soft);
  color: var(--ink);
}

.nav-title {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--ink);
}

.nav-sub {
  display: block;
  font-size: 0.78rem;
  line-height: 1.4;
  color: var(--ink-faint);
}

.sidebar .external {
  border-top: 1px solid var(--rule);
  padding-top: 1rem;
  font-size: 0.85rem;
}

.sidebar .external a { color: var(--ink-soft); }

/* Content */

main {
  padding: 2.5rem 3rem 6rem;
  min-width: 0;
}

main > :first-child { margin-top: 0; }

h1, h2, h3, h4 {
  line-height: 1.25;
  letter-spacing: -0.015em;
  margin: 2.4rem 0 0.8rem;
}

h1 { font-size: 2.1rem; margin-top: 0; }
h2 { font-size: 1.45rem; padding-top: 1.2rem; border-top: 1px solid var(--rule); }
h3 { font-size: 1.12rem; }
h4 { font-size: 1rem; color: var(--ink-soft); }

p, ul, ol { margin: 0 0 1.1rem; }

a { color: var(--accent); text-underline-offset: 2px; }

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

blockquote {
  margin: 1.2rem 0;
  padding: 0.1rem 1.1rem;
  border-left: 3px solid var(--rule);
  color: var(--ink-soft);
}

/* Alerts, expanded from GitHub's > [!IMPORTANT] blocks. */

.callout {
  margin: 1.4rem 0;
  padding: 1rem 1.2rem 0.4rem;
  border-radius: 8px;
  border: 1px solid var(--rule);
  background: var(--bg-raised);
  border-left-width: 4px;
}

.callout-label {
  margin: 0 0 0.5rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.callout-important, .callout-warning { border-left-color: var(--warn); }
.callout-important .callout-label, .callout-warning .callout-label { color: var(--warn); }
.callout-caution { border-left-color: var(--bad); }
.callout-caution .callout-label { color: var(--bad); }
.callout-note, .callout-tip { border-left-color: var(--good); }
.callout-note .callout-label, .callout-tip .callout-label { color: var(--good); }

/* Code */

code, pre, kbd {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

code {
  font-size: 0.875em;
  background: var(--bg-sunken);
  padding: 0.12em 0.36em;
  border-radius: 4px;
}

pre {
  background: var(--bg-sunken);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 0.9rem 1.1rem;
  overflow-x: auto;
  font-size: 0.85rem;
  line-height: 1.55;
}

pre code {
  background: none;
  padding: 0;
  font-size: inherit;
}

/* Tables. The protocol document is mostly tables, and several are wider than a phone. */

.table-scroll, table { display: block; overflow-x: auto; max-width: 100%; }

table {
  border-collapse: collapse;
  margin: 1.3rem 0;
  font-size: 0.9rem;
  white-space: nowrap;
}

th, td {
  border: 1px solid var(--rule);
  padding: 0.45rem 0.7rem;
  text-align: left;
  vertical-align: top;
  white-space: normal;
}

th { background: var(--bg-sunken); font-weight: 600; }

/* Footer */

footer {
  margin-top: 4rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--rule);
  font-size: 0.83rem;
  color: var(--ink-faint);
}

footer a { color: var(--ink-soft); }

/* Narrow screens: the navigation becomes a header rather than a column. */

@media (max-width: 60rem) {
  .shell { grid-template-columns: minmax(0, 1fr); }
  .sidebar {
    position: static;
    max-height: none;
    border-right: 0;
    border-bottom: 1px solid var(--rule);
    padding: 1.5rem 1.25rem;
  }
  .nav-sub { display: none; }
  .sidebar ul { margin-bottom: 1rem; }
  main { padding: 2rem 1.25rem 4rem; }
  h1 { font-size: 1.7rem; }
}