* {
  box-sizing: border-box;
}

:root {
  color-scheme: light dark;
  --bg: #f7f7f4;
  --panel: #ffffff;
  --text: #20211f;
  --muted: #676b63;
  --line: #ddded8;
  --accent: #23857d;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111410;
    --panel: #1b1f19;
    --text: #f3f4ef;
    --muted: #b7bbaf;
    --line: #30362e;
    --accent: #6ed3c7;
  }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.75;
}

header,
main,
footer {
  width: min(880px, calc(100% - 32px));
  margin: 0 auto;
}

header {
  padding: 56px 0 24px;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

nav a {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 12px;
  background: var(--panel);
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 6vw, 3.5rem);
  line-height: 1.1;
  letter-spacing: 0;
}

h2 {
  margin: 36px 0 12px;
  font-size: 1.35rem;
  line-height: 1.35;
}

p,
ul {
  margin: 0 0 16px;
}

ul {
  padding-left: 1.4rem;
}

.lead {
  margin-top: 16px;
  color: var(--muted);
  font-size: 1.08rem;
}

.panel {
  margin: 20px 0;
  padding: 22px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.meta {
  color: var(--muted);
  font-size: 0.95rem;
}

footer {
  padding: 36px 0 56px;
  color: var(--muted);
  border-top: 1px solid var(--line);
  margin-top: 44px;
}