:root {
  --bg: #ffffff;
  --bg-soft: #f6f8fa;
  --bg-code: #0d1117;
  --text: #1c2128;
  --text-soft: #57606a;
  --border: #d8dee4;
  --accent: #2f6f9f;
  --accent-soft: #e8f0f7;
  --radius: 10px;
  --sidebar: 250px;
  --toc: 200px;
  --measure: 46rem;
}

:root[data-theme="dark"] {
  --bg: #0f1419;
  --bg-soft: #161b22;
  --bg-code: #0d1117;
  --text: #e2e8ef;
  --text-soft: #98a4b3;
  --border: #262d36;
  --accent: #6cb6f0;
  --accent-soft: #17222e;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1419;
    --bg-soft: #161b22;
    --bg-code: #0d1117;
    --text: #e2e8ef;
    --text-soft: #98a4b3;
    --border: #262d36;
    --accent: #6cb6f0;
    --accent-soft: #17222e;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 5rem; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

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

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
  z-index: 20;
  background: var(--bg);
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.85rem 1.5rem;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 640;
  letter-spacing: -0.01em;
  color: var(--text);
  font-size: 1.05rem;
}

.brand-mark { display: inline-flex; line-height: 0; }
.brand-mark svg { display: block; }

.header-nav {
  display: flex;
  gap: 1.35rem;
  margin-left: auto;
  font-size: 0.94rem;
}
.header-nav a { color: var(--text-soft); }
.header-nav a:hover { color: var(--text); text-decoration: none; }

.menu-toggle {
  display: none;
  margin-left: auto;
  padding: 0.4rem 0.8rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  font: inherit;
  font-size: 0.9rem;
  cursor: pointer;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text-soft);
  cursor: pointer;
  padding: 0;
}
.theme-toggle:hover { color: var(--text); }
.theme-toggle .icon-sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}

/* Layout ------------------------------------------------------------- */

.layout {
  display: grid;
  grid-template-columns: var(--sidebar) minmax(0, 1fr) var(--toc);
  gap: 2.5rem;
  max-width: 84rem;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
  align-items: start;
}

.sidebar {
  position: sticky;
  top: 5rem;
  max-height: calc(100vh - 7rem);
  overflow-y: auto;
}

.nav-section {
  margin: 1.5rem 0 0.4rem;
  font-size: 0.76rem;
  font-weight: 660;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-soft);
}
.nav-section:first-child { margin-top: 0; }

.sidebar-nav ul { list-style: none; margin: 0; padding: 0; }
.sidebar-nav li { margin: 0; }
.sidebar-nav a {
  display: block;
  padding: 0.3rem 0.65rem;
  margin-left: -0.65rem;
  border-radius: 7px;
  color: var(--text-soft);
  font-size: 0.93rem;
}
.sidebar-nav a:hover { background: var(--bg-soft); color: var(--text); text-decoration: none; }
.sidebar-nav a.active { background: var(--accent-soft); color: var(--accent); font-weight: 560; }
.sidebar-nav a.external::after { content: " \2197"; font-size: 0.85em; opacity: 0.7; }

.content { max-width: var(--measure); min-width: 0; }

.page-toc {
  position: sticky;
  top: 5rem;
  font-size: 0.88rem;
}
.page-toc p {
  margin: 0 0 0.5rem;
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-soft);
  font-weight: 660;
}
.page-toc ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--border); }
.page-toc li { margin: 0; }
.page-toc a { display: block; padding: 0.22rem 0 0.22rem 0.8rem; color: var(--text-soft); }
.page-toc a:hover { color: var(--accent); text-decoration: none; }

/* Typography --------------------------------------------------------- */

h1, h2, h3, h4 { line-height: 1.25; letter-spacing: -0.015em; }
h1 { font-size: 2.1rem; margin: 0 0 1rem; }
h2 { font-size: 1.42rem; margin: 2.6rem 0 0.9rem; padding-top: 0.4rem; }
h3 { font-size: 1.12rem; margin: 2rem 0 0.6rem; }
h4 { font-size: 1rem; margin: 1.5rem 0 0.5rem; }

p, ul, ol { margin: 0 0 1.05rem; }
li { margin: 0.3rem 0; }

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

blockquote {
  margin: 1.4rem 0;
  padding: 0.9rem 1.1rem;
  border-left: 3px solid var(--accent);
  background: var(--bg-soft);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-soft);
}
blockquote p:last-child { margin-bottom: 0; }

code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.88em;
}

:not(pre) > code {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.1em 0.35em;
}

pre {
  background: var(--bg-code);
  border-radius: var(--radius);
  padding: 1rem 1.15rem;
  overflow-x: auto;
  margin: 0 0 1.2rem;
  /* The block is dark in both themes, so its border is too; the light theme
     border was showing as pale corners around it. */
  border: 1px solid #2a313b;
}
pre code { color: #e6edf3; }
.codehilite { margin: 0 0 1.2rem; }
.codehilite pre { margin: 0; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 1.4rem;
  font-size: 0.94rem;
  display: block;
  overflow-x: auto;
}
th, td { text-align: left; padding: 0.55rem 0.8rem; border-bottom: 1px solid var(--border); vertical-align: top; }
th { font-weight: 620; background: var(--bg-soft); }

.content ol { counter-reset: none; }
.content ol > li { padding-left: 0.2rem; }

.edit-link { margin-top: 3.5rem; font-size: 0.88rem; color: var(--text-soft); }

/* Landing ------------------------------------------------------------ */

.landing-content {
  max-width: 62rem;
  margin: 0 auto;
  padding: 3.5rem 1.5rem 5rem;
}

.landing-content h1 {
  font-size: clamp(2.3rem, 5vw, 3.2rem);
  letter-spacing: -0.03em;
  margin-bottom: 1.1rem;
  max-width: 20ch;
}

.landing-content .lede {
  font-size: 1.2rem;
  color: var(--text-soft);
  max-width: 40rem;
}

.landing-content h2 {
  margin-top: 3.6rem;
  font-size: 1.6rem;
}

.landing-content > p,
.landing-content > ul,
.landing-content > ol { max-width: var(--measure); }

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 2rem 0 1rem;
}
.cta a {
  display: inline-block;
  padding: 0.62rem 1.15rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-weight: 560;
  font-size: 0.96rem;
}
.cta a:first-child {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.cta a:hover { text-decoration: none; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  gap: 1rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}
.cards li {
  margin: 0;
  padding: 1.15rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-soft);
}
.cards li p { margin: 0.4rem 0 0; font-size: 0.94rem; color: var(--text-soft); }
.cards li a { font-weight: 600; }

.split {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(20rem, 1fr));
  gap: 1.5rem 2.5rem;
  align-items: start;
}

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

.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 1.5rem 3rem;
  color: var(--text-soft);
  font-size: 0.88rem;
}
.site-footer p { max-width: 60rem; margin: 0 auto; }

@media (max-width: 68rem) {
  .layout { grid-template-columns: var(--sidebar) minmax(0, 1fr); }
  .page-toc { display: none; }
}

@media (max-width: 52rem) {
  .layout { grid-template-columns: minmax(0, 1fr); gap: 1.5rem; padding-top: 1.5rem; }
  .sidebar { display: none; position: static; max-height: none; border-bottom: 1px solid var(--border); padding-bottom: 1rem; }
  .sidebar.open { display: block; }
  .header-nav { display: none; }
  .menu-toggle { display: inline-flex; }
  .landing .theme-toggle { margin-left: auto; }
  .landing-content { padding-top: 2.5rem; }
  .landing-content h1 { font-size: 2.1rem; }
}