:root {
  --bg: #fafafa;
  --fg: #1a1a1a;
  --sidebar-bg: #f5f5f5;
  --sidebar-fg: #333;
  --accent: #333;
  --accent-hover: #555;
  --border: #e0e0e0;
  --code-bg: #f5f5f5;
  --max-width: 860px;
  --sidebar-width: 220px;
}

[data-theme="dark"] {
  --bg: #141414;
  --fg: #fafafa;
  --sidebar-bg: #1a1a1a;
  --sidebar-fg: #ccc;
  --accent: #ccc;
  --accent-hover: #fff;
  --border: #2a2a2a;
  --code-bg: #1e1e1e;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: "SF Mono", "Fira Code", "Cascadia Code", monospace;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  font-size: 14px;
}

.site-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 1rem;
  background: var(--sidebar-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 60;
}

.site-header .site-title {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--fg);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.theme-toggle {
  margin-left: auto;
  background: none;
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.2rem 0.5rem;
  font-size: 1rem;
  cursor: pointer;
  color: var(--fg);
}
.theme-toggle:hover { background: var(--border); }

.layout {
  display: flex;
  min-height: calc(100vh - 40px);
}

.sidebar {
  width: var(--sidebar-width);
  background: var(--sidebar-bg);
  color: var(--sidebar-fg);
  padding: 1.5rem 1rem;
  border-right: 1px solid var(--border);
  overflow-y: auto;
  position: sticky;
  top: 40px;
  height: calc(100vh - 40px);
  flex-shrink: 0;
}

.sidebar-header {
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 1.5rem;
  letter-spacing: -0.02em;
}

.sidebar-header a { color: inherit; text-decoration: none; }

.sidebar-group { margin-bottom: 1.2rem; }
.sidebar-group h3 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 0.4rem;
  opacity: 0.7;
}

.sidebar ul { list-style: none; }
.sidebar li { margin-bottom: 0.1rem; }
.sidebar a {
  color: var(--sidebar-fg);
  text-decoration: none;
  font-size: 0.85rem;
  display: block;
  padding: 0.2rem 0.5rem;
  border-radius: 3px;
}
.sidebar a:hover { background: var(--border); }
.sidebar li.active a {
  background: var(--fg);
  color: var(--bg);
}

.sidebar-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.2rem 0.5rem;
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--fg);
}

.content {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 2.5rem 4rem;
}

article h1 {
  font-size: 1.6rem;
  margin-bottom: 1rem;
  letter-spacing: -0.03em;
  font-weight: 700;
}
article h2 {
  font-size: 1.2rem;
  margin: 2rem 0 0.75rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.3rem;
  letter-spacing: -0.02em;
}
article h3 { font-size: 1rem; margin: 1.5rem 0 0.5rem; }
article p { margin-bottom: 1rem; }
article ul, article ol { margin: 0.5rem 0 1rem 1.5rem; }
article li { margin-bottom: 0.3rem; }
article a { color: var(--accent); }
article a:hover { color: var(--accent-hover); }

article pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1rem;
  overflow-x: auto;
  margin-bottom: 1rem;
  font-size: 0.85rem;
  line-height: 1.5;
}

article code {
  font-family: inherit;
  font-size: 0.9em;
}

article p code, article li code {
  background: var(--code-bg);
  padding: 0.1em 0.3em;
  border-radius: 2px;
}

article table {
  border-collapse: collapse;
  width: 100%;
  margin-bottom: 1rem;
  font-size: 0.9rem;
}
article td, article th {
  border: 1px solid var(--border);
  padding: 0.4rem 0.6rem;
  text-align: left;
}

article hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2rem 0;
}

.breadcrumb {
  font-size: 0.8rem;
  color: var(--accent);
  opacity: 0.7;
  margin-bottom: 1rem;
}

.prev-next {
  display: flex;
  justify-content: space-between;
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}
.prev-next a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.85rem;
}
.prev-next a:hover { color: var(--accent-hover); }

.site-footer {
  text-align: center;
  padding: 1rem;
  font-size: 0.75rem;
  color: var(--accent);
  opacity: 0.5;
  border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: calc(-1 * var(--sidebar-width) - 20px);
    top: 0;
    z-index: 50;
    transition: left 0.3s;
  }
  .sidebar.open { left: 0; }
  .sidebar-toggle { display: block; }
  .content { padding: 3rem 1rem 2rem; }
}