:root {
  --primary: #1F6FEB;
  --primary-dark: #1A5BC4;
  --primary-light: #E8F1FF;
  --text: #11181C;
  --muted: #5B6770;
  --border: #E2E6EA;
  --bg: #FFFFFF;
  --bg-alt: #F5F7F9;
  --max: 820px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Noto Sans JP", system-ui, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255,255,255,0.9);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav {
  max-width: 1040px; margin: 0 auto; padding: 14px 20px;
  display: flex; align-items: center; gap: 16px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; color: var(--text); }
.brand:hover { text-decoration: none; }
.logo {
  width: 30px; height: 30px; border-radius: 8px;
  object-fit: cover; display: block;
}
.nav-links { margin-left: auto; display: flex; gap: 20px; font-size: 14px; font-weight: 600; }
.nav-links a { color: var(--muted); }
.nav-links a:hover { color: var(--text); text-decoration: none; }

/* hero */
.hero {
  background: linear-gradient(180deg, var(--primary-light), #fff);
  border-bottom: 1px solid var(--border);
  text-align: center; padding: 72px 20px 64px;
}
.hero .logo-lg { width: 72px; height: 72px; border-radius: 18px; object-fit: cover; display: inline-block; margin-bottom: 20px; box-shadow: 0 8px 24px rgba(31,111,235,0.25); }
.hero h1 { font-size: 40px; margin: 0 0 12px; letter-spacing: -0.5px; }
.hero p { font-size: 18px; color: var(--muted); max-width: 600px; margin: 0 auto; }
.badge { display:inline-block; margin-top: 22px; background: var(--bg-alt); border:1px solid var(--border); border-radius: 999px; padding: 8px 16px; font-size: 13px; color: var(--muted); }

/* features */
.features { max-width: 1040px; margin: 56px auto; padding: 0 20px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature { background: var(--bg-alt); border: 1px solid var(--border); border-radius: 16px; padding: 22px; }
.feature .icon { font-size: 26px; }
.feature h3 { margin: 10px 0 6px; font-size: 16px; }
.feature p { margin: 0; font-size: 14px; color: var(--muted); }

/* document pages */
.doc { max-width: var(--max); margin: 48px auto 80px; padding: 0 20px; }
.doc h1 { font-size: 32px; margin: 0 0 6px; }
.doc .updated { color: var(--muted); font-size: 14px; margin: 0 0 36px; }
.doc h2 { font-size: 20px; margin: 40px 0 12px; padding-top: 8px; }
.doc h3 { font-size: 16px; margin: 24px 0 8px; }
.doc p, .doc li { font-size: 15.5px; color: #25303a; }
.doc ul { padding-left: 22px; }
.doc li { margin: 6px 0; }
.doc table { width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 14.5px; }
.doc th, .doc td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; vertical-align: top; }
.doc th { background: var(--bg-alt); font-weight: 700; }
.callout { background: var(--primary-light); border: 1px solid #cfe0ff; border-radius: 12px; padding: 14px 16px; font-size: 14.5px; }
.toc { background: var(--bg-alt); border: 1px solid var(--border); border-radius: 12px; padding: 16px 20px; margin: 0 0 32px; }
.toc strong { font-size: 13px; color: var(--muted); }
.toc ol { margin: 8px 0 0; padding-left: 20px; font-size: 14px; }

/* footer */
.site-footer { border-top: 1px solid var(--border); background: var(--bg-alt); }
.footer-inner { max-width: 1040px; margin: 0 auto; padding: 32px 20px; display: flex; flex-wrap: wrap; gap: 16px; align-items: center; font-size: 14px; color: var(--muted); }
.footer-links { margin-left: auto; display: flex; gap: 18px; }

@media (max-width: 720px) {
  .features { grid-template-columns: 1fr; }
  .hero h1 { font-size: 30px; }
  .nav-links { gap: 14px; }
}