:root{
  --bg:#ffffff;
  --ink:#1b1b1f;
  --muted:#5a5d66;
  --line:#ececf2;
  --card:#fafafc;
  --accent:#cc6699; /* elegant rose */
}
*{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:1.8;letter-spacing:.02em}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:960px;margin:0 auto;padding:24px}
.header{display:flex;align-items:center;justify-content:space-between;padding:14px 24px;border-bottom:1px solid var(--line);position:sticky;top:0;background:rgba(255,255,255,.9);backdrop-filter:saturate(160%) blur(6px)}
.brand{display:flex;align-items:center;gap:12px;color:var(--ink);text-decoration:none}
.brand svg{width:30px;height:30px}
.brand .title{font-weight:800;letter-spacing:.02em}
.nav a{margin-left:16px;color:var(--muted)}
.hero{padding:56px 24px 24px}
.hero h1{font-size:clamp(1.8rem,3vw,2.4rem);margin:0 0 8px;line-height:1.3}
.hero p{margin:0;color:var(--muted)}
.grid{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(--muted)}
.main{padding:24px}
.prose h1,.prose h2{line-height:1.35}
.prose h2{margin-top:1.4em}
.note{font-size:.92rem;color:var(--muted)}
.tips{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
.tip{border:1px dashed var(--line);border-radius:12px;padding:12px;background:#fff}
.footer{border-top:1px solid var(--line);padding:24px;color:var(--muted);font-size:.92rem}
.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:2px 6px}
@media (max-width:760px){.grid{grid-template-columns:1fr}.tips{grid-template-columns:1fr}}