:root {
  --accent: #159957;
  --accent-2: #155799;
  --ink: #1b1f23;
  --muted: #6a737d;
  --line: #eaecef;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  line-height: 1.65;
  background: #fff;
}
.hero {
  background: linear-gradient(120deg, var(--accent-2), var(--accent));
  color: #fff;
  padding: 3.5rem 1.25rem 3rem;
  text-align: center;
}
.hero h1 { margin: 0; font-size: 2rem; font-weight: 700; }
.hero .sub { margin: .6rem 0 0; opacity: .92; font-size: 1.05rem; }
.hero .meta { margin: .9rem 0 0; opacity: .8; font-size: .85rem; }
main {
  max-width: 760px;
  margin: 0 auto;
  padding: 2.2rem 1.25rem 4rem;
}
h2 {
  margin-top: 2.6rem;
  padding-bottom: .35rem;
  border-bottom: 1px solid var(--line);
  font-size: 1.5rem;
}
h3 { margin-top: 1.9rem; font-size: 1.15rem; }
p, li { font-size: 1rem; }
ul, ol { padding-left: 1.4rem; }
li { margin: .35rem 0; }
a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }
code {
  background: #f6f8fa;
  padding: .15em .4em;
  border-radius: 5px;
  font-size: .9em;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}
.divider { height: 1px; background: var(--line); border: 0; margin: 2.8rem 0; }
.lang-tag {
  display: inline-block;
  font-size: .8rem;
  letter-spacing: .04em;
  text-transform: uppercase;
  color: var(--muted);
  background: #f6f8fa;
  padding: .2rem .6rem;
  border-radius: 999px;
  margin-bottom: .4rem;
}
nav.foot {
  max-width: 760px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
  text-align: center;
  color: var(--muted);
  font-size: .9rem;
  border-top: 1px solid var(--line);
}
nav.foot a { margin: 0 .5rem; }