/*
 * The HoloML site (browser milestone 22): plain pages, light and dark,
 * with the system's own fonts, so that nothing is fetched from other
 * sites. Every colour pair meets WCAG 2.2 AA (4.5:1 for text, 3:1 for
 * borders that matter); site/site.test.ts checks them.
 */
:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --surface: #f4f6f9;
  --fg: #1b1e24;
  --muted: #4d5566;
  --link: #0a58a8;
  --visited: #6a3d9a;
  --border: #8a93a3;
  --rule: #d9dee6;
  --must: #9b1c1c;
  --note: #0a58a8;
  --hl-tag: #7b2a8e;
  --hl-attr: #8a4600;
  --hl-value: #0b6b34;
  --hl-comment: #5b6371;
  --hl-keyword: #0a58a8;
  --focus: #0a58a8;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418;
    --surface: #1b2028;
    --fg: #e7e9ee;
    --muted: #aab2c0;
    --link: #8ec3ff;
    --visited: #c9a6f5;
    --border: #6b7486;
    --rule: #2c323d;
    --must: #ff9d94;
    --note: #8ec3ff;
    --hl-tag: #e0a8ff;
    --hl-attr: #f5bd7a;
    --hl-value: #8ddba3;
    --hl-comment: #a0a9b8;
    --hl-keyword: #8ec3ff;
    --focus: #8ec3ff;
  }
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 1.0625rem/1.6 system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

a {
  color: var(--link);
  text-underline-offset: 0.15em;
}

a:visited {
  color: var(--visited);
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 2px;
}

.skip {
  position: absolute;
  left: 1rem;
  top: -4rem;
  padding: 0.5rem 1rem;
  background: var(--bg);
  color: var(--link);
  border: 2px solid var(--focus);
  z-index: 10;
}

.skip:focus {
  top: 0.5rem;
}

/* The bar at the top: the site's name and its parts. */
.bar {
  border-bottom: 1px solid var(--rule);
  background: var(--surface);
}

.bar nav {
  max-width: 72rem;
  margin: 0 auto;
  padding: 0.6rem 1rem;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.25rem 1.5rem;
}

.bar .home {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--fg);
  text-decoration: none;
}

.bar ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.1rem;
}

.bar a:visited {
  color: var(--link);
}

.bar .here,
.bar [aria-current='page'] {
  color: var(--fg);
  font-weight: 600;
  text-decoration-thickness: 2px;
}

main {
  max-width: 50rem;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
  /* A long address breaks rather than widen the page on a phone. */
  overflow-wrap: break-word;
}

body.spec main {
  max-width: 56rem;
}

.crumbs ol {
  list-style: none;
  margin: 0 0 0.5rem;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.crumbs li + li::before {
  content: '›';
  margin-right: 0.35rem;
}

h1,
h2,
h3,
h4 {
  line-height: 1.25;
  margin: 2rem 0 0.75rem;
}

h1 {
  font-size: 2.1rem;
  margin-top: 0.5rem;
}

h2 {
  font-size: 1.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--rule);
}

h3 {
  font-size: 1.2rem;
}

h1 code,
h2 code,
h3 code {
  font-size: 0.95em;
}

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

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

code,
pre {
  font-family: ui-monospace, 'Cascadia Code', 'SF Mono', Menlo, Consolas, 'Liberation Mono', monospace;
  font-size: 0.9em;
}

:not(pre) > code {
  background: var(--surface);
  padding: 0.1em 0.3em;
  border-radius: 4px;
  overflow-wrap: anywhere;
}

pre {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0.8rem 1rem;
  overflow-x: auto;
  line-height: 1.45;
  tab-size: 2;
}

pre[data-lang]::before {
  content: attr(data-lang);
  display: block;
  margin-bottom: 0.4rem;
  color: var(--muted);
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  font-size: 0.8rem;
}

.hl-tag {
  color: var(--hl-tag);
}

.hl-attr {
  color: var(--hl-attr);
}

.hl-value {
  color: var(--hl-value);
}

.hl-comment {
  color: var(--hl-comment);
  font-style: italic;
}

.hl-keyword {
  color: var(--hl-keyword);
  font-weight: 600;
}

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

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 0.95rem;
}

th,
td {
  text-align: left;
  vertical-align: top;
  padding: 0.4rem 0.6rem;
  border-bottom: 1px solid var(--rule);
}

th {
  border-bottom: 2px solid var(--border);
}

/*
 * Code in a table breaks only at its spaces, and the names in its first
 * column not at all; a table too wide for the screen scrolls in its own
 * region. The last column is most often words: room enough to read them.
 */
td code,
th code {
  overflow-wrap: normal;
}

td:first-child code {
  white-space: nowrap;
}

td:last-child {
  min-width: 12rem;
}

/* The specification's requirement words (BCP 14), as W3C specifications mark them. */
em.rfc2119 {
  font-style: normal;
  font-weight: 600;
  color: var(--must);
  letter-spacing: 0.02em;
}

p.note,
p.informative {
  border-left: 4px solid var(--note);
  background: var(--surface);
  padding: 0.6rem 0.9rem;
  border-radius: 0 6px 6px 0;
}

p.informative {
  font-style: italic;
}

.subtitle {
  font-size: 1.2rem;
  color: var(--muted);
  margin-top: -0.25rem;
}

/* The specification's contents. */
.toc {
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0 1.25rem 0.5rem;
  margin: 2rem 0;
}

.toc h2 {
  border: none;
  margin-top: 1rem;
}

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

.toc ul ul {
  padding-left: 1.5rem;
  margin: 0.25rem 0 0.5rem;
}

/* The example sites on the home page, as cards. */
ul.sites {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
  gap: 1.25rem;
}

ul.sites li {
  margin: 0;
  border: 1px solid var(--rule);
  border-radius: 8px;
  overflow: hidden;
  padding-bottom: 0.75rem;
  background: var(--surface);
}

ul.sites img {
  display: block;
  width: 100%;
  height: auto;
  margin-bottom: 0.6rem;
}

ul.sites li > :not(img) {
  margin-left: 0.9rem;
  margin-right: 0.9rem;
}

img {
  max-width: 100%;
  height: auto;
}

footer.bar {
  border-top: 1px solid var(--rule);
  border-bottom: none;
  color: var(--muted);
  font-size: 0.95rem;
}

footer.bar div {
  max-width: 72rem;
  margin: 0 auto;
  padding: 1rem;
}

footer.bar p {
  margin: 0.25rem 0;
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

@media print {
  .bar,
  .skip,
  .crumbs {
    display: none;
  }

  pre {
    white-space: pre-wrap;
  }
}