/* The site's only stylesheet. System fonts, phone first, light or dark follows the system. */

:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --text: #1b1b1f;
  --muted: #5d5f66;
  --line: #dedfe3;
  --link: #0b57d0;
  --code-bg: #f3f4f6;
  --measure: 42rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121316;
    --text: #e6e6e9;
    --muted: #a3a6ad;
    --line: #2e3036;
    --link: #8ab4f8;
    --code-bg: #1e2025;
  }
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", "Noto Sans SC", sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  overflow-wrap: break-word;
}

.wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 1rem;
}

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

a:hover {
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

/* Skip link: out of sight until a keyboard user tabs to it. */
.skip {
  position: absolute;
  left: -999px;
  top: 0.5rem;
  padding: 0.25rem 0.5rem;
  background: var(--bg);
}

.skip:focus {
  left: 0.5rem;
}

/* Header: site name and language switch on one row, the page menu below (wraps on phones). */
.site-header {
  border-bottom: 1px solid var(--line);
}

.site-header .wrap {
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
}

.bar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  color: var(--text);
  font-weight: 700;
  text-decoration: none;
}

.lang {
  font-size: 0.9rem;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1rem;
  margin-top: 0.5rem;
  font-size: 0.95rem;
}

nav a {
  color: var(--muted);
  text-decoration: none;
}

nav a:hover {
  color: var(--text);
  text-decoration: underline;
}

nav a[aria-current="page"] {
  color: var(--text);
  font-weight: 600;
}

/* Reading column. */
main {
  padding-top: 1.5rem;
  padding-bottom: 2.5rem;
}

h1,
h2,
h3 {
  line-height: 1.3;
}

h1 {
  font-size: 1.75rem;
  margin: 0.5rem 0 1rem;
}

h2 {
  font-size: 1.3rem;
  margin: 2rem 0 0.75rem;
}

h3 {
  font-size: 1.1rem;
  margin: 1.5rem 0 0.5rem;
}

p,
ul,
ol,
blockquote,
pre,
.table-wrap {
  margin: 0 0 1rem;
}

ul,
ol {
  padding-left: 1.5rem;
}

blockquote {
  margin-left: 0;
  padding-left: 1rem;
  border-left: 3px solid var(--line);
  color: var(--muted);
}

hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 2rem 0;
}

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

/* Code. Shell blocks get selected whole with one click, so commands copy easily without any script. */
code,
pre {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.9em;
}

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

pre {
  background: var(--code-bg);
  padding: 0.75rem 1rem;
  border-radius: 6px;
  overflow-x: auto;
  line-height: 1.5;
}

pre code.language-sh,
pre code.language-bash,
pre code.language-shell {
  -webkit-user-select: all;
  user-select: all;
}

/* Tables keep readable columns and scroll sideways on narrow screens. */
.table-wrap {
  overflow-x: auto;
}

table {
  border-collapse: collapse;
  width: 100%;
}

th,
td {
  min-width: 7rem;
  padding: 0.4rem 0.6rem;
  border: 1px solid var(--line);
  vertical-align: top;
}

th {
  background: var(--code-bg);
}

th:not([align]) {
  text-align: start;
}

/* Footer. */
.site-footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer .wrap {
  padding-top: 1.25rem;
  padding-bottom: 2rem;
}

.site-footer p {
  margin: 0 0 0.35rem;
}

.site-footer .links {
  margin-top: 0.75rem;
}

/* Language picker at the site root. */
.picker {
  padding-top: 3rem;
}

.choices {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.choices a {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  font-weight: 600;
  text-decoration: none;
}

.choices a:hover {
  border-color: var(--link);
}

@media (min-width: 48rem) {
  body {
    font-size: 1.0625rem;
  }

  h1 {
    font-size: 2.1rem;
  }
}