:root {
  --bg: #ffffff;
  --bg-soft: #f5f7fb;
  --text: #16202e;
  --muted: #5b6678;
  --line: #e3e8f0;
  --accent: #1f5eff;
  --accent-soft: #e8efff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

a { color: var(--accent); }

.wrap { max-width: 960px; margin: 0 auto; padding: 0 20px; }

header.site {
  border-bottom: 1px solid var(--line);
  background: var(--bg);
}
header.site .wrap {
  display: flex; align-items: center; justify-content: space-between;
  min-height: 64px; gap: 16px; flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 700; }
.brand img { width: 32px; height: 32px; border-radius: 8px; }
nav a { margin-left: 18px; text-decoration: none; color: var(--muted); font-size: 15px; }
nav a:hover, nav a[aria-current] { color: var(--text); }

.hero { background: var(--bg-soft); border-bottom: 1px solid var(--line); padding: 56px 0 48px; }
.hero h1 { font-size: 36px; line-height: 1.2; margin: 0 0 14px; }
.hero p { font-size: 18px; color: var(--muted); max-width: 680px; margin: 0; }

section { padding: 40px 0; }
section + section { border-top: 1px solid var(--line); }
h2 { font-size: 24px; margin: 0 0 14px; }
h3 { font-size: 17px; margin: 22px 0 6px; }

.grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-top: 18px; }
@media (max-width: 640px) { .grid { grid-template-columns: 1fr; } }
.card { border: 1px solid var(--line); border-radius: 12px; padding: 18px; background: var(--bg); }
.card h3 { margin-top: 0; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }

.flow { margin-top: 18px; border: 1px solid var(--line); border-radius: 12px; padding: 16px; background: var(--bg-soft); overflow-x: auto; }
.flow svg { display: block; width: 100%; min-width: 640px; height: auto; }

.note { background: var(--accent-soft); border-radius: 10px; padding: 14px 16px; }

.doc { max-width: 760px; }
.doc .updated { color: var(--muted); margin-top: -6px; }

footer.site { border-top: 1px solid var(--line); padding: 26px 0 40px; color: var(--muted); font-size: 14px; }
footer.site .wrap { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
footer.site a { color: var(--muted); margin-right: 16px; }

@media (max-width: 600px) {
  .hero h1 { font-size: 28px; }
  nav a { margin: 0 14px 0 0; }
}