:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #1c1e21;
  --muted: #57606a;
  --border: #d0d7de;
  --code-bg: #f6f8fa;
  --link: #0969da;
  --header-bg: #f6f8fa;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --fg: #e6edf3;
    --muted: #9198a1;
    --border: #30363d;
    --code-bg: #161b22;
    --link: #4493f8;
    --header-bg: #161b22;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
}

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 1.5rem;
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--fg);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.site-header nav {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.site-header nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
}

.site-header nav a:hover {
  color: var(--link);
}

main {
  max-width: 860px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

h1, h2, h3 {
  line-height: 1.25;
}

h1 {
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
}

h2 {
  margin-top: 2.5rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.3rem;
}

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

code {
  background: var(--code-bg);
  border-radius: 4px;
  padding: 0.15em 0.4em;
  font-size: 0.9em;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1rem;
  overflow-x: auto;
}

pre code {
  background: none;
  padding: 0;
}

pre.mermaid {
  background: none;
  border: none;
  padding: 0;
  text-align: center;
}

table {
  border-collapse: collapse;
  width: 100%;
  margin: 1.25rem 0;
  display: block;
  overflow-x: auto;
}

th, td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

th {
  background: var(--code-bg);
}

blockquote {
  margin: 1rem 0;
  padding: 0.25rem 1rem;
  border-left: 3px solid var(--border);
  color: var(--muted);
}

.site-footer {
  text-align: center;
  padding: 2rem 1rem 3rem;
  color: var(--muted);
  font-size: 0.9rem;
}