/* mechinterp.io — plain CSS, no build step. Light by default, dark via prefers-color-scheme. */
:root {
  --bg: #fbfaf7;
  --fg: #1d1d1f;
  --muted: #5f6368;
  --rule: #e4e1da;
  --accent: #b5452b;      /* Golden-Gate-adjacent orange-red, kept dark enough for AA contrast */
  --card: #ffffff;
  --code-bg: #f1eee8;
  --max: 42rem;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141416;
    --fg: #e8e6e3;
    --muted: #a3a3a8;
    --rule: #2c2c30;
    --accent: #f08a6c;
    --card: #1b1b1e;
    --code-bg: #222226;
  }
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 1.0625rem/1.65 var(--serif);
}
a { color: var(--accent); text-underline-offset: 0.18em; }
a:hover { text-decoration-thickness: 2px; }
img { max-width: 100%; height: auto; }
code, pre { font-family: var(--mono); font-size: 0.9em; background: var(--code-bg); border-radius: 4px; }
code { padding: 0.1em 0.35em; }
pre { padding: 1rem; overflow-x: auto; }

.skip { position: absolute; left: -999px; }
.skip:focus { left: 1rem; top: 1rem; background: var(--card); padding: 0.5rem 0.75rem; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }

header.site {
  border-bottom: 1px solid var(--rule);
  font-family: var(--sans);
}
header.site .wrap {
  display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between;
  gap: 0.5rem 1.5rem; padding-top: 1.1rem; padding-bottom: 1.1rem;
}
.brand { color: var(--fg); text-decoration: none; font-weight: 650; letter-spacing: -0.01em; font-size: 1.05rem; }
.brand span { color: var(--accent); }
nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: 1.25rem; }
nav a { color: var(--muted); text-decoration: none; font-size: 0.95rem; }
nav a:hover, nav a[aria-current="page"] { color: var(--fg); }

main { padding: 3rem 0 4rem; }
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.015em; }
h1 { font-size: clamp(2rem, 5vw, 2.75rem); margin: 0 0 1rem; }
h2 { font-size: 1.45rem; margin: 2.75rem 0 0.75rem; }
h3 { font-size: 1.1rem; margin: 1.75rem 0 0.4rem; }
.lede { font-size: 1.2rem; color: var(--muted); margin-top: 0; }
.eyebrow { font-family: var(--sans); font-size: 0.8rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--accent); margin: 0 0 0.75rem; }

.cards { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); margin: 1.5rem 0; }
.card {
  background: var(--card); border: 1px solid var(--rule); border-radius: 8px; padding: 1.1rem 1.2rem;
}
.card h3 { margin-top: 0; font-family: var(--sans); font-size: 1rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.97rem; }

.topics { padding-left: 1.2rem; }
.topics li { margin: 0.35rem 0; }

.empty {
  border: 1px dashed var(--rule); border-radius: 8px; padding: 1.5rem; text-align: center;
  color: var(--muted); font-family: var(--sans); font-size: 0.95rem;
}

footer.site { border-top: 1px solid var(--rule); font-family: var(--sans); font-size: 0.85rem; color: var(--muted); }
footer.site .wrap { padding-top: 1.5rem; padding-bottom: 2rem; display: flex; flex-wrap: wrap; gap: 0.5rem 1.5rem; justify-content: space-between; }
footer.site a { color: var(--muted); }