/* KeepValid — brand teal #6c9b9a, near-monochrome, no framework. */
:root {
  --accent: #6c9b9a;
  --accent-deep: #4f7776;
  --ink: #15201f;
  --ink-soft: #5b6a69;
  --bg: #fbfcfc;
  --surface: #ffffff;
  --line: #e4eae9;
  --radius: 16px;
  --measure: 68ch;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #eef3f2;
    --ink-soft: #9db0ae;
    --bg: #101615;
    --surface: #172120;
    --line: #26332f;
    --accent: #83b3b2;
    --accent-deep: #a7ccca;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: var(--measure); margin: 0 auto; padding: 0 24px; }

header.site {
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  position: sticky; top: 0; backdrop-filter: saturate(180%) blur(14px); z-index: 10;
}
header.site .wrap { display: flex; align-items: center; gap: 12px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 650; letter-spacing: -0.01em; color: var(--ink); text-decoration: none; }
.brand svg { width: 26px; height: 26px; }
header.site nav { margin-left: auto; display: flex; gap: 20px; }
header.site nav a { color: var(--ink-soft); text-decoration: none; font-size: 15px; }
header.site nav a:hover, header.site nav a[aria-current="page"] { color: var(--accent-deep); }

.hero { padding: 88px 0 64px; text-align: center; }
.hero .mark { width: 96px; height: 96px; margin-bottom: 28px; }
h1 { font-size: clamp(34px, 6vw, 52px); line-height: 1.08; letter-spacing: -0.025em; margin: 0 0 16px; }
.lede { font-size: clamp(18px, 2.4vw, 21px); color: var(--ink-soft); margin: 0 auto; max-width: 54ch; }

.pill {
  display: inline-block; margin-top: 32px; padding: 10px 20px;
  border: 1px solid var(--line); border-radius: 999px;
  color: var(--ink-soft); font-size: 15px; background: var(--surface);
}

.features { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); padding: 8px 0 72px; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.card h3 { margin: 0 0 6px; font-size: 17px; letter-spacing: -0.01em; }
.card p { margin: 0; color: var(--ink-soft); font-size: 15px; }

main.doc { padding: 56px 0 88px; }
main.doc h1 { text-align: left; font-size: clamp(30px, 5vw, 40px); }
main.doc h2 { margin: 40px 0 12px; font-size: 21px; letter-spacing: -0.015em; }
main.doc h3 { margin: 28px 0 8px; font-size: 17px; }
main.doc p, main.doc li { color: var(--ink); }
main.doc ul { padding-left: 22px; }
main.doc li { margin: 6px 0; }
.updated { color: var(--ink-soft); font-size: 15px; margin-top: -4px; }

.callout {
  border-left: 3px solid var(--accent);
  background: var(--surface);
  padding: 16px 20px; border-radius: 0 var(--radius) var(--radius) 0; margin: 28px 0;
}
.callout p { margin: 0; }

a { color: var(--accent-deep); }
code { font: 0.92em ui-monospace, SFMono-Regular, Menlo, monospace; background: var(--surface); border: 1px solid var(--line); border-radius: 6px; padding: 1px 6px; }

footer.site { border-top: 1px solid var(--line); padding: 32px 0 56px; color: var(--ink-soft); font-size: 15px; }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 8px 24px; align-items: center; }
footer.site nav { margin-left: auto; display: flex; gap: 20px; flex-wrap: wrap; }
footer.site a { color: var(--ink-soft); text-decoration: none; }
footer.site a:hover { color: var(--accent-deep); }