/* Modern: clean neutral surfaces, flat cards with a hairline shadow, and a blue accent. */
:root {
  --bg: #ffffff; --surface: #f5f7fa; --fg: #1f2328; --muted: #5c6470; --border: #e1e5eb;
  --accent: #1f5fc7; --accent-fg: #ffffff; --accent-soft: #e9f1fd; --mark: #fff1a6;
  --code-bg: #f3f5f8; --code-fg: #1f2328;
  --font-body: system-ui, -apple-system, "Segoe UI", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", Meiryo, sans-serif;
  --font-heading: var(--font-body);
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;
  --radius: 8px; --radius-lg: 12px; --content-width: 1080px; --prose-width: 760px;
  --shadow: 0 1px 2px rgb(16 24 40 / .05), 0 1px 3px rgb(16 24 40 / .08);
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418; --surface: #1a1f26; --fg: #e6e9ee; --muted: #9ba4b0; --border: #2b323c;
    --accent: #78aefc; --accent-fg: #0b1526; --accent-soft: #1b2b44; --mark: #6b5a1e;
    --code-bg: #0b0e12; --code-fg: #e6e9ee;
    --shadow: 0 1px 3px rgb(0 0 0 / .5);
  }
}
.site-title { font-weight: 700; letter-spacing: -.01em; }
.page-title, .article-title { letter-spacing: -.01em; }
.prose pre { border: 1px solid var(--border); }
.prose h2 { border-bottom-width: 1px; }
.card { border-color: var(--border); }