:root {
  --ink: #1a1a19;
  --muted: #61646a;
  --line: #dcdcd6;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 48px 20px;
  background: #fdfdfb;
  color: var(--ink);
  font: 17px/1.85 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
}

main {
  max-width: 620px;
  margin: 0 auto;
}

h1 {
  font-size: 32px;
  line-height: 1.3;
  margin: 0 0 20px;
  letter-spacing: -0.01em;
}

h2 {
  font-size: 18px;
  margin: 40px 0 10px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

p { margin: 0 0 14px; }

button {
  font: inherit;
  padding: 10px 18px;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: #fff;
  border-radius: 3px;
  cursor: pointer;
}

button:hover { background: #000; }

pre {
  margin: 14px 0 0;
  padding: 14px 16px;
  background: #f4f4f1;
  border-radius: 0;
  font-size: 14px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-all;
}

ul { padding-left: 22px; }
li { margin: 6px 0; }

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