:root {
  --bg: #edf0f4; --surface: #fff; --ink: #1a2130; --muted: #586174; --line: #d3d9e3; --accent: #2b45d6;
  --font-ui: 'Zen Kaku Gothic New', 'Hiragino Sans', 'Yu Gothic', 'Noto Sans JP', system-ui, sans-serif;
  --font-display: 'Dela Gothic One', 'Zen Kaku Gothic New', 'Hiragino Sans', sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #0d121a; --surface: #161c27; --ink: #e6eaf2; --muted: #9aa4b8; --line: #2a3243; --accent: #8197ff; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--font-ui); line-height: 1.85; padding: 32px 16px 64px; }
main { max-width: 760px; margin: 0 auto; }
.back { display: inline-block; margin-bottom: 16px; color: var(--accent); font-weight: 700; text-decoration: none; }
.back:hover { text-decoration: underline; }
article { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 28px 24px; }
h1 { font-family: var(--font-display); font-weight: 400; font-size: clamp(24px, 5vw, 32px); margin: 0 0 4px; line-height: 1.4; }
.updated { color: var(--muted); font-size: 14px; margin: 0 0 24px; }
h2 { font-size: 18px; margin: 32px 0 8px; padding-left: 10px; border-left: 4px solid var(--accent); line-height: 1.5; }
p, li { font-size: 15px; }
ul, ol { padding-left: 1.4em; }
a { color: var(--accent); }
.nav-legal { margin-top: 24px; display: flex; gap: 16px; flex-wrap: wrap; font-size: 14px; }