:root {
  color-scheme: light dark;
  --accent: #00796b;
  --surface: #ffffff;
  --background: #f4faf8;
  --text: #17201e;
  --muted: #5d6966;
  --border: #d9e5e1;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
  line-height: 1.8;
}

header, main, footer {
  width: min(100% - 32px, 820px);
  margin-inline: auto;
}

header { padding: 40px 0 20px; }
main {
  padding: 28px clamp(20px, 5vw, 48px);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: 0 8px 30px rgb(0 60 50 / 6%);
}
footer { padding: 24px 0 48px; color: var(--muted); font-size: .85rem; }

h1 { margin: 0; font-size: clamp(1.65rem, 5vw, 2.2rem); line-height: 1.35; }
h2 { margin: 2.2rem 0 .55rem; font-size: 1.2rem; }
h3 { margin: 1.4rem 0 .4rem; font-size: 1rem; }
p, ul, ol { margin: .55rem 0; }
a { color: var(--accent); text-underline-offset: 3px; }
.brand { color: var(--accent); font-weight: 700; margin-bottom: 6px; }
.updated { color: var(--muted); font-size: .9rem; }
.links { display: grid; gap: 12px; margin-top: 24px; }
.links a {
  display: block;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-radius: 12px;
  text-decoration: none;
  font-weight: 600;
}
.notice { padding: 14px 16px; background: var(--background); border-radius: 10px; }

@media (prefers-color-scheme: dark) {
  :root {
    --accent: #63d6bf;
    --surface: #17201e;
    --background: #0e1513;
    --text: #eef7f4;
    --muted: #afbfba;
    --border: #34433f;
  }
}