:root {
  --bg: #f7f7f5;
  --fg: #1d1f21;
  --muted: #5d6266;
  --card: #ffffff;
  --line: #e2e2df;
  --accent: #2f6f5e;
  --radius: 10px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16181a;
    --fg: #e8e8e6;
    --muted: #a2a7ab;
    --card: #1e2124;
    --line: #2c3034;
    --accent: #7fc3ab;
  }
}

* { box-sizing: border-box; }

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

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

.site-header,
.site-footer {
  max-width: 760px;
  margin: 0 auto;
  padding: 18px 20px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  align-items: center;
  justify-content: space-between;
}

.site-header { border-bottom: 1px solid var(--line); }
.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 40px;
  color: var(--muted);
  font-size: 14px;
}

.brand { display: inline-flex; align-items: center; gap: 9px; text-decoration: none; color: inherit; }
.mark {
  display: inline-grid;
  place-items: center;
  width: 28px; height: 28px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
}
.brand-text { font-weight: 600; letter-spacing: .01em; }

nav { display: flex; gap: 16px; font-size: 15px; }
nav a { color: var(--muted); text-decoration: none; }
nav a:hover { color: var(--fg); }

main { max-width: 760px; margin: 0 auto; padding: 28px 20px 8px; }

h1 { font-size: 30px; line-height: 1.25; margin: 0 0 12px; letter-spacing: -.01em; }
h2 { font-size: 20px; margin: 34px 0 10px; }
h3 { font-size: 16px; margin: 0 0 6px; }

.lead { font-size: 17px; color: var(--muted); margin-top: 0; }

p, li { overflow-wrap: anywhere; }

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

.cards { list-style: none; padding: 0; margin: 0; display: grid; gap: 14px; grid-template-columns: 1fr; }
@media (min-width: 640px) { .cards { grid-template-columns: repeat(3, 1fr); } }

.cards li {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}
.cards p { margin: 0; color: var(--muted); font-size: 15px; }

ul { padding-left: 20px; }

.back { display: inline-block; margin-top: 8px; }