/*
 * Nous — the whole stylesheet for the whole site.
 *
 * Hand-written, no build step, no framework. System fonts only: there is no
 * webfont, no script and no third-party request anywhere on this site, which is
 * what makes the privacy policy's claims true of the page you read them on.
 *
 * Light and dark are both first-class. The light palette is defined on bare
 * :root; the dark block redefines only the tokens.
 */

:root {
  color-scheme: light dark;
  --fg: #16181d;
  --muted: #5b6270;
  --bg: #ffffff;
  --rule: #e3e6ec;
  --accent: #2b5cd9;
  --card: #f6f7fa;
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #e6e8ee;
    --muted: #9aa2b1;
    --bg: #14161a;
    --rule: #2a2e37;
    --accent: #7ea2ff;
    --card: #1b1e24;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
}

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

/* Visible keyboard focus everywhere, never removed. */
a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 2px;
}

/* Skip link: off-screen until focused. */
.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--bg);
  color: var(--fg);
  padding: .6rem 1rem;
  z-index: 10;
}
.skip:focus {
  left: .5rem;
  top: .5rem;
  outline: 2px solid var(--accent);
}

/* ---- Site chrome ---------------------------------------------------- */

.site-nav {
  border-bottom: 1px solid var(--rule);
  background: var(--bg);
}
.site-nav > div {
  max-width: 52rem;
  margin: 0 auto;
  padding: .9rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.site-nav .wordmark {
  font-weight: 600;
  letter-spacing: -.01em;
  color: var(--fg);
  text-decoration: none;
  font-size: 1.05rem;
}
.site-nav ul {
  list-style: none;
  display: flex;
  gap: 1.25rem;
  margin: 0;
  padding: 0;
  font-size: .9375rem;
}
.site-nav a[aria-current="page"] { color: var(--fg); font-weight: 600; }

main {
  max-width: 44rem;
  margin: 0 auto;
  padding: 3rem 1.25rem 5rem;
}
main.wide { max-width: 52rem; }

h1 { font-size: 1.85rem; line-height: 1.2; margin: 0 0 .35rem; letter-spacing: -.015em; }
h2 { font-size: 1.15rem; margin: 2.5rem 0 .6rem; letter-spacing: -.01em; }
h3 { font-size: 1rem; margin: 1.6rem 0 .4rem; }
p, li { margin: 0 0 .8rem; }
ul, ol { padding-left: 1.25rem; }

.lede { color: var(--muted); margin-bottom: .25rem; }
.revised { color: var(--muted); font-size: .875rem; margin: 0 0 2rem; }
hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0; }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: .875em;
  background: var(--card);
  padding: .1em .35em;
  border-radius: .25em;
}

/* Tables scroll on their own rather than making the page scroll sideways. */
table {
  border-collapse: collapse;
  width: 100%;
  margin: 0 0 1rem;
  font-size: .9375rem;
  display: block;
  overflow-x: auto;
}
th, td {
  text-align: left;
  vertical-align: top;
  padding: .5rem .6rem;
  border-bottom: 1px solid var(--rule);
}
th { font-weight: 600; }

.note {
  background: var(--card);
  border-radius: .5rem;
  padding: .9rem 1.1rem;
  margin: 0 0 1.2rem;
}

.site-footer {
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: .875rem;
}
.site-footer > div {
  max-width: 52rem;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}
.site-footer ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin: 0 0 .75rem;
  padding: 0;
}
.site-footer p { margin: 0; }

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

.hero { padding: 4rem 0 1rem; }
.hero h1 {
  font-size: clamp(2rem, 6vw, 3rem);
  line-height: 1.1;
  margin-bottom: .75rem;
}
.hero .tagline {
  font-size: clamp(1.05rem, 2.5vw, 1.25rem);
  color: var(--muted);
  max-width: 34rem;
  margin-bottom: 1.5rem;
}
.status {
  display: inline-block;
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: .35rem .9rem;
  font-size: .875rem;
  color: var(--muted);
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
  gap: 1.25rem;
  margin-top: 1.25rem;
  padding: 0;
  list-style: none;
}
.features li {
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: .5rem;
  padding: 1.1rem 1.2rem;
  margin: 0;
}
.features h3 { margin: 0 0 .35rem; }
.features p { margin: 0; color: var(--muted); font-size: .9375rem; }

.callout {
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: .5rem;
  padding: 1.5rem;
  margin-top: 1.25rem;
}
.callout p:last-child { margin-bottom: 0; }

@media (max-width: 30rem) {
  .site-nav ul { gap: .9rem; font-size: .875rem; }
  .hero { padding-top: 2.5rem; }
}