:root {
  --brand: #3D5AFE;
  --ink: #111318;
  --muted: #5b6072;
  --line: #e4e6ee;
  --bg: #ffffff;
  --card: #f6f7fb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --ink: #f2f3f7; --muted: #a2a8bd; --line: #2a2e3c;
    --bg: #0e1015; --card: #171a22;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
}
.wrap { max-width: 720px; margin: 0 auto; padding: 0 24px; }
header.site {
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; background: var(--bg); z-index: 5;
}
header.site .wrap {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px; gap: 16px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; text-decoration: none; color: var(--ink); }
.brand .mark {
  width: 30px; height: 30px; border-radius: 8px; background: var(--brand);
  display: grid; place-items: center; color: #fff; font-size: 15px; font-weight: 800;
}
nav a { color: var(--muted); text-decoration: none; margin-left: 18px; font-size: 15px; }
nav a:hover { color: var(--ink); }
h1 { font-size: clamp(30px, 5vw, 44px); line-height: 1.15; letter-spacing: -0.02em; margin: 48px 0 12px; }
h2 { font-size: 20px; margin: 36px 0 8px; letter-spacing: -0.01em; }
h3 { font-size: 16px; margin: 24px 0 6px; }
p, li { color: var(--ink); }
.lede { font-size: 19px; color: var(--muted); margin: 0 0 28px; }
.muted { color: var(--muted); }
.small { font-size: 14px; color: var(--muted); }
ul { padding-left: 22px; }
li { margin: 6px 0; }
.cta {
  display: inline-block; background: var(--brand); color: #fff; text-decoration: none;
  padding: 13px 22px; border-radius: 12px; font-weight: 600;
}
.cta:hover { filter: brightness(1.07); }
.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 32px 0 8px; }
.feature { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px 18px; }
.feature h3 { margin: 0 0 4px; font-size: 15px; }
.feature p { margin: 0; font-size: 14px; color: var(--muted); }
table { border-collapse: collapse; width: 100%; margin: 14px 0; font-size: 15px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-weight: 600; }
.notice { background: var(--card); border: 1px solid var(--line); border-left: 3px solid var(--brand); border-radius: 10px; padding: 14px 18px; margin: 22px 0; }
footer.site { border-top: 1px solid var(--line); margin-top: 64px; padding: 28px 0 48px; }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 12px 22px; justify-content: space-between; align-items: center; }
footer.site a { color: var(--muted); text-decoration: none; }
footer.site a:hover { color: var(--ink); }
code { background: var(--card); padding: 2px 6px; border-radius: 5px; font-size: 90%; }