:root{
  --bg:#ffffff;
  --ink:#111111;
  --sub:#555555;
  --brand:#222222;
  --accent:#7a5cff;
  --card:#f6f7fb;
  --line:#e9e9ef;
}
*{box-sizing:border-box}
html{font-size:16px}
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans JP", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  color:var(--ink);
  background:var(--bg);
  line-height:1.7;
  letter-spacing:0.02em;
}
.container{max-width:980px;margin:0 auto;padding:24px}
.header{
  display:flex;align-items:center;justify-content:space-between;
  padding:16px 24px;border-bottom:1px solid var(--line);position:sticky;top:0;background:rgba(255,255,255,.9);backdrop-filter:saturate(160%) blur(6px);
}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink)}
.logo svg{width:36px;height:36px}
.logo-title{font-weight:800;font-size:1.125rem;letter-spacing:.02em}
.nav a{margin-left:16px;color:var(--sub);text-decoration:none}
.hero{padding:64px 24px 32px}
.hero h1{font-size:clamp(1.8rem,3.2vw,2.6rem);line-height:1.2;margin:0 0 12px}
.hero p{color:var(--sub);margin:0}
.section{padding:32px 24px}
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px}
.card h3{margin:0 0 8px;font-size:1rem}
.card p{margin:0;color:var(--sub)}
.kbd{font-family:ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;background:#f2f2f6;border:1px solid var(--line);border-radius:6px;padding:1px 6px}
.footer{border-top:1px solid var(--line);padding:24px;color:var(--sub);font-size:.9rem}
.cta{display:inline-block;background:var(--ink);color:#fff;text-decoration:none;padding:10px 16px;border-radius:999px;margin-top:12px}
.small{font-size:.92rem;color:var(--sub)}
.grid-2{display:grid;grid-template-columns:1.1fr .9fr;gap:24px}
@media (max-width: 760px){
  .cards{grid-template-columns:1fr}
  .grid-2{grid-template-columns:1fr}
  .header{position:relative}
}