:root {
  --bg: #f7f5fb;
  --surface: #ffffff;
  --text: #1f1d2b;
  --muted: #5d5a70;
  --border: #e4e0ef;
  --accent: #6b4fd8;
  --accent-soft: #efeafd;
  --hero-from: #f78c9e;
  --hero-mid: #8c5cd9;
  --hero-to: #232e73;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14131c;
    --surface: #1d1b28;
    --text: #ecebf3;
    --muted: #a9a6bd;
    --border: #2e2b3d;
    --accent: #b19cff;
    --accent-soft: #2a2442;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Segoe UI", sans-serif;
  line-height: 1.75;
}

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

.wrap { max-width: 760px; margin: 0 auto; padding: 0 20px; }

/* ヘッダー */
.top-nav {
  display: flex; justify-content: space-between; align-items: center;
  padding: 16px 0; font-size: 14px;
}
.top-nav .brand { display: flex; align-items: center; gap: 8px; font-weight: 700; color: var(--text); text-decoration: none; }
.top-nav .brand img { width: 28px; height: 28px; }
.top-nav nav { display: flex; gap: 16px; }
.top-nav nav a { color: var(--muted); text-decoration: none; }
.top-nav nav a:hover { color: var(--accent); }

/* ヒーロー */
.hero {
  background: linear-gradient(135deg, var(--hero-from), var(--hero-mid) 50%, var(--hero-to));
  color: #fff; border-radius: 24px; padding: 48px 32px; text-align: center; margin: 8px 0 40px;
}
.hero img { width: 112px; height: 112px; filter: drop-shadow(0 8px 20px rgba(0,0,0,.25)); }
.hero h1 { margin: 12px 0 4px; font-size: 36px; letter-spacing: .01em; }
.hero p { margin: 0 auto; max-width: 520px; font-size: 17px; opacity: .95; }
.hero .meta { margin-top: 16px; font-size: 13px; opacity: .85; }

h2 { font-size: 22px; margin: 44px 0 12px; }
h3 { font-size: 17px; margin: 24px 0 6px; }

.features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; padding: 0; list-style: none; }
.features li { background: var(--surface); border: 1px solid var(--border); border-radius: 14px; padding: 16px; }
.features strong { display: block; margin-bottom: 2px; }
.features span { color: var(--muted); font-size: 14px; }

ol.steps { padding-left: 1.4em; }
ol.steps li { margin: 6px 0; }

kbd {
  font-family: inherit; font-size: .9em; background: var(--accent-soft); border: 1px solid var(--border);
  border-radius: 6px; padding: 1px 6px;
}

details {
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 12px 16px; margin: 8px 0;
}
details summary { cursor: pointer; font-weight: 600; }
details p, details ol, details ul { color: var(--muted); margin: 8px 0 0; }

.contact {
  background: var(--accent-soft); border-radius: 16px; padding: 20px 24px; margin-top: 12px;
}
.contact a { font-weight: 600; word-break: break-all; }

.doc p, .doc li { color: var(--text); }
.doc .updated { color: var(--muted); font-size: 14px; }

footer {
  margin: 56px 0 32px; padding-top: 16px; border-top: 1px solid var(--border);
  color: var(--muted); font-size: 13px; display: flex; flex-wrap: wrap; gap: 16px; justify-content: space-between;
}
footer a { color: var(--muted); }

@media (max-width: 520px) {
  .hero { padding: 36px 20px; border-radius: 18px; }
  .hero h1 { font-size: 30px; }
  .features { grid-template-columns: 1fr; }
  .top-nav nav { gap: 12px; }
}