:root {
  --blue: #1B5FFE;
  --ink: #1a1a1a;
  --muted: #5a5a5a;
  --line: #e6e6e6;
  --bg: #ffffff;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
}
.nav {
  position: sticky; top: 0;
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 24px;
  background: rgba(255,255,255,0.92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 18px; color: var(--ink); text-decoration: none; }
.brand .dot { width: 26px; height: 26px; border-radius: 7px; background: var(--blue); display: inline-block; }
.nav-links { display: flex; gap: 18px; }
.nav-links a { color: var(--muted); text-decoration: none; font-weight: 600; font-size: 15px; }
.nav-links a:hover { color: var(--blue); }
.wrap { max-width: 760px; margin: 0 auto; padding: 40px 24px 80px; }
h1 { font-size: 34px; letter-spacing: -0.02em; margin: 8px 0 6px; }
h2 { font-size: 22px; margin: 36px 0 10px; letter-spacing: -0.01em; }
h3 { font-size: 17px; margin: 22px 0 6px; }
p, li { color: var(--ink); font-size: 16px; }
.muted { color: var(--muted); }
.updated { color: var(--muted); font-size: 14px; margin-bottom: 24px; }
a { color: var(--blue); }
ul { padding-left: 22px; }
li { margin: 6px 0; }
.callout {
  border: 1px solid var(--line);
  background: #f7f9ff;
  border-radius: 14px;
  padding: 16px 18px;
  margin: 20px 0;
}
.callout strong { color: var(--blue); }
.footer { border-top: 1px solid var(--line); padding: 28px 24px; text-align: center; color: var(--muted); font-size: 14px; }
.hero { text-align: center; padding: 70px 24px 40px; }
.hero .logo { width: 76px; height: 76px; border-radius: 20px; background: var(--blue); margin: 0 auto 22px; }
.hero h1 { font-size: 40px; }
.hero p { color: var(--muted); font-size: 18px; max-width: 560px; margin: 8px auto 0; }
.cards { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-top: 34px; }
.card { border: 1px solid var(--line); border-radius: 16px; padding: 22px; width: 240px; text-align: left; text-decoration: none; color: var(--ink); transition: transform .12s ease, border-color .12s ease; }
.card:hover { transform: translateY(-2px); border-color: var(--blue); }
.card h3 { margin: 0 0 4px; color: var(--ink); }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 15px; }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--line); }
th { font-weight: 600; color: var(--ink); background: #fafafa; }
td { color: var(--muted); }
h4 { font-size: 16px; margin: 18px 0 6px; color: var(--ink); }
ol { padding-left: 22px; }
ol li { margin: 6px 0; }
code { background: #f2f2f7; padding: 2px 6px; border-radius: 4px; font-size: 14px; }