:root {
  --bg: #f7f7f5;
  --surface: #ffffff;
  --text: #1f2328;
  --muted: #656d76;
  --border: #d8dee4;
  --accent: #2563eb;
  --accent-text: #ffffff;
  --radius: 10px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --surface: #181b21;
    --text: #e6e8eb;
    --muted: #9aa3ad;
    --border: #2d333b;
    --accent: #60a5fa;
    --accent-text: #0f1115;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.7;
}
a { color: var(--accent); }
.wrap { max-width: 880px; margin: 0 auto; padding: 24px 16px 64px; }
.site-header { display: flex; align-items: baseline; gap: 12px; margin-bottom: 24px; }
.site-header a { color: var(--text); text-decoration: none; font-weight: 700; font-size: 1.25rem; }
h1 { font-size: 1.6rem; margin: 0 0 8px; }
.lead { color: var(--muted); margin: 0 0 24px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.tool-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 12px; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
.tool-list a { display: block; height: 100%; text-decoration: none; color: inherit; }
.tool-list a:hover .card { border-color: var(--accent); }
.tool-list .name { font-weight: 700; }
.tool-list .desc { color: var(--muted); font-size: .9rem; }
.tool-list .date { color: var(--muted); font-size: .8rem; }
button, .btn {
  font: inherit; border: 1px solid var(--accent); background: var(--accent); color: var(--accent-text);
  border-radius: 8px; padding: 8px 16px; cursor: pointer;
}
button.secondary { background: transparent; color: var(--accent); }
input, textarea, select {
  font: inherit; color: var(--text); background: var(--surface);
  border: 1px solid var(--border); border-radius: 8px; padding: 8px 10px; max-width: 100%;
}
textarea { width: 100%; min-height: 160px; }
.site-footer { margin-top: 48px; color: var(--muted); font-size: .85rem; }
.site-nav { display: flex; flex-wrap: wrap; gap: 4px 16px; margin: 0 0 24px; font-size: .9rem; }
.site-nav a { color: var(--muted); text-decoration: none; }
.site-nav a:hover { color: var(--accent); }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 4px 16px; margin-bottom: 8px; }
.site-footer a { color: var(--muted); }
.prose h2 { font-size: 1.2rem; margin: 32px 0 8px; }
.prose h3 { font-size: 1.05rem; margin: 24px 0 6px; }
.prose p, .prose li { margin: 0 0 10px; }
.prose dt { font-weight: 700; margin-top: 12px; }
.prose dd { margin: 0 0 8px; }
.email-box { font-size: 1.1rem; font-weight: 700; word-break: break-all; }