:root {
  --bg: #f7f6f2;
  --surface: #ffffff;
  --text: #1c1b19;
  --muted: #5f5c55;
  --line: #e4e1d8;
  --accent: #2f6b4f;
  --accent-ink: #ffffff;
  --radius: 14px;
  --max: 760px;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121311;
    --surface: #1b1d1a;
    --text: #ecebe6;
    --muted: #a5a39b;
    --line: #2c2f2a;
    --accent: #7fc6a0;
    --accent-ink: #0e1a13;
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, sans-serif;
}

a { color: var(--accent); text-underline-offset: 3px; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

header.site {
  border-bottom: 1px solid var(--line);
}
header.site .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding-top: 18px; padding-bottom: 18px;
}
.brand { font-weight: 700; letter-spacing: -0.01em; color: var(--text); text-decoration: none; }
header.site nav { display: flex; gap: 18px; flex-wrap: wrap; font-size: 15px; }
header.site nav a { color: var(--muted); text-decoration: none; }
header.site nav a:hover, header.site nav a[aria-current="page"] { color: var(--text); }

main { padding: 56px 0 72px; }

h1 { font-size: clamp(32px, 6vw, 48px); line-height: 1.1; letter-spacing: -0.02em; margin: 0 0 16px; }
h2 { font-size: 24px; letter-spacing: -0.01em; margin: 48px 0 12px; }
h3 { font-size: 18px; margin: 28px 0 6px; }
p, ul, ol { margin: 0 0 14px; }
li { margin: 4px 0; }
.lead { font-size: 20px; color: var(--muted); max-width: 620px; }
.meta { color: var(--muted); font-size: 15px; }

.cards { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); margin-top: 20px; }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px;
}
.card h3 { margin-top: 0; }
.card p:last-child { margin-bottom: 0; }
a.card { display: block; color: inherit; text-decoration: none; }
a.card:hover { border-color: var(--accent); }

.levels { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0 14px; padding: 0; list-style: none; }
.levels li {
  margin: 0; padding: 4px 12px; border-radius: 999px; font-size: 15px;
  border: 1px solid var(--line); background: var(--surface);
}

.button {
  display: inline-block; padding: 12px 20px; border-radius: 999px;
  background: var(--accent); color: var(--accent-ink); font-weight: 600; text-decoration: none;
}
.button[aria-disabled="true"] { opacity: 0.6; pointer-events: none; }

.note {
  border-left: 3px solid var(--accent); padding: 4px 0 4px 16px; color: var(--muted); margin: 24px 0;
}

details { border-bottom: 1px solid var(--line); padding: 14px 0; }
details summary { cursor: pointer; font-weight: 600; }
details p { margin: 10px 0 0; }

footer.site { border-top: 1px solid var(--line); padding: 28px 0 40px; font-size: 15px; color: var(--muted); }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between; }
footer.site nav { display: flex; flex-wrap: wrap; gap: 8px 18px; }
footer.site a { color: var(--muted); }