:root {
  --bg: #f4f7fb;
  --ink: #0f1b2d;
  --muted: #5a6a80;
  --card: #fff;
  --line: #dbe3ef;
  --accent: #0b9bb8;
  --accent-deep: #087a92;
  --dark: #0b1628;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(800px 400px at 0% 0%, rgba(11, 155, 184, 0.12), transparent 60%),
    radial-gradient(700px 360px at 100% 0%, rgba(47, 91, 234, 0.1), transparent 55%),
    var(--bg);
  line-height: 1.75;
}
a { color: var(--accent-deep); }
.wrap { max-width: 820px; margin: 0 auto; padding: 1.5rem 1.15rem 3.5rem; }
.topnav { display: flex; flex-wrap: wrap; align-items: center; gap: 0.75rem 1rem; margin-bottom: 1.25rem; font-size: 0.9rem; }
.topnav a { color: var(--muted); text-decoration: none; }
.topnav a:hover { color: var(--accent-deep); }
.lang-switch {
  margin-left: auto;
  display: inline-flex;
  gap: 0.35rem;
  align-items: center;
  padding: 0.2rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
}
.lang-switch a {
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
}
.lang-switch a.is-active {
  background: var(--accent-deep);
  color: #fff;
}
.lang-switch a:hover { color: var(--accent-deep); }
.lang-switch a.is-active:hover { color: #fff; }
.hero {
  background: linear-gradient(135deg, var(--dark), var(--accent) 125%);
  color: #fff;
  border-radius: 16px;
  padding: 1.5rem 1.25rem;
  margin-bottom: 1.5rem;
}
.hero h1 { margin: 0 0 0.65rem; font-size: clamp(1.35rem, 3.6vw, 1.85rem); line-height: 1.35; }
.hero p { margin: 0; opacity: 0.92; }
.code {
  display: inline-block;
  margin-top: 0.9rem;
  padding: 0.4rem 0.8rem;
  border-radius: 999px;
  background: rgba(255,255,255,.16);
  font-weight: 700;
  letter-spacing: 0.03em;
}
.cta {
  display: inline-flex;
  margin-top: 1rem;
  margin-right: 0.6rem;
  padding: 0.65rem 1rem;
  border-radius: 11px;
  background: #fff;
  color: var(--accent-deep);
  text-decoration: none;
  font-weight: 700;
}
.cta.ghost { background: transparent; color: #fff; border: 1px solid rgba(255,255,255,.35); }
article h2 { margin: 1.75rem 0 0.6rem; font-size: 1.25rem; }
article h3 { margin: 1.25rem 0 0.45rem; font-size: 1.05rem; }
article p, article li { color: #243247; }
article ul { padding-left: 1.2rem; }
.box {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1rem 1.1rem;
  margin: 1rem 0;
}
.box strong { color: var(--accent-deep); }
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; margin: 1rem 0; }
th, td { border: 1px solid var(--line); padding: 0.55rem 0.65rem; text-align: left; }
th { background: #eef5fa; }
.related { margin-top: 2rem; padding-top: 1rem; border-top: 1px solid var(--line); }
.related a { display: block; margin: 0.35rem 0; }
.tags { margin-top: 1.5rem; color: var(--muted); font-size: 0.85rem; }
footer { margin-top: 1.5rem; color: var(--muted); font-size: 0.85rem; }