:root {
  color-scheme: light;
  --ink: #163044;
  --muted: #526576;
  --accent: #096b9e;
  --line: #d6e3ec;
  --paper: #fff;
  --background: #f4f8fb;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 100%;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--background); color: var(--ink); line-height: 1.85; }
a { color: var(--accent); text-underline-offset: .22em; overflow-wrap: anywhere; }
a:hover { text-decoration-thickness: .13em; }
a:focus-visible { outline: 3px solid #0578b4; outline-offset: 5px; border-radius: 2px; }
.skip-link { position: absolute; top: -5rem; left: 1rem; background: white; padding: .6rem 1rem; z-index: 10; }
.skip-link:focus { top: .5rem; }
.site-header { max-width: 64rem; margin: auto; padding: 1.4rem 2rem; display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.brand { font-size: 1.2rem; font-weight: 750; text-decoration: none; color: var(--ink); }
nav { display: flex; gap: 1.3rem; flex-wrap: wrap; font-size: .95rem; }
nav a { text-decoration: none; padding: .35rem 0; }
nav a[aria-current="page"] { font-weight: 700; border-bottom: 2px solid var(--accent); }
main { max-width: 60rem; margin: 0 auto; padding: 0 1.5rem; }
article { background: var(--paper); border: 1px solid var(--line); border-top: 5px solid #1689c3; border-radius: .7rem; padding: clamp(1.4rem, 5vw, 3.7rem); }
h1 { font-size: clamp(1.7rem, 4vw, 2.35rem); line-height: 1.35; margin: 0 0 1.1rem; letter-spacing: -.03em; }
h1 + p { color: var(--muted); font-size: .93rem; padding-bottom: 1.5rem; border-bottom: 1px solid var(--line); }
h2 { font-size: 1.3rem; line-height: 1.5; margin: 2.2rem 0 .6rem; }
h3 { font-size: 1.05rem; margin: 1.5rem 0 .4rem; }
p { margin: .7rem 0; overflow-wrap: anywhere; }
ul { margin: .7rem 0; padding-left: 1.4rem; }
li { margin: .55rem 0; }
footer { max-width: 60rem; margin: 1.5rem auto 2.5rem; padding: 0 1.5rem; color: var(--muted); font-size: .88rem; display: flex; justify-content: space-between; gap: .3rem 1rem; flex-wrap: wrap; }
footer p { margin: 0; }
@media (max-width: 36rem) {
  .site-header { padding: 1rem; gap: .6rem; }
  .brand { width: 100%; }
  main { padding: 0 .65rem; }
  article { padding: 1.3rem 1.1rem; }
  footer { padding: 0 1rem; }
}
@media print {
  body { background: white; }
  .site-header, footer, .skip-link { display: none; }
  main { max-width: none; padding: 0; }
  article { padding: 0; border: 0; }
  a { color: inherit; }
}