:root {
  --bg: #fafafa;
  --fg: #1a1a1a;
  --muted: #6b7280;
  --border: #e5e7eb;
  --code-bg: #f3f4f6;
  --link: #2563eb;
  --accent: #3b82f6;
  --sidebar-bg: #f9fafb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111827;
    --fg: #e5e7eb;
    --muted: #9ca3af;
    --border: #374151;
    --code-bg: #1f2937;
    --link: #60a5fa;
    --accent: #3b82f6;
    --sidebar-bg: #1f2937;
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, sans-serif;
  line-height: 1.7;
  color: var(--fg);
  background: var(--bg);
  display: flex;
  max-width: 1400px;
  margin: 0 auto;
}

/* Sidebar / TOC */
#TOC {
  position: fixed;
  top: 0;
  left: 0;
  width: 280px;
  height: 100vh;
  overflow-y: auto;
  padding: 2rem 1.5rem;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  font-size: 0.85rem;
  z-index: 10;
}

#TOC ul { list-style: none; padding-left: 0; }
#TOC > ul > li { margin-bottom: 0.5rem; }
#TOC ul ul { padding-left: 1rem; }
#TOC a {
  color: var(--muted);
  text-decoration: none;
  display: block;
  padding: 0.2rem 0;
  border-radius: 4px;
  transition: color 0.15s;
}
#TOC a:hover { color: var(--link); }
#TOC > ul > li > a { font-weight: 600; color: var(--fg); }

/* Main content */
.content {
  margin-left: 280px;
  padding: 3rem 4rem;
  max-width: 800px;
  width: 100%;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  line-height: 1.3;
  font-weight: 700;
}
h1 { font-size: 2.2rem; margin-top: 0; border-bottom: 2px solid var(--accent); padding-bottom: 0.5rem; }
h2 { font-size: 1.6rem; border-bottom: 1px solid var(--border); padding-bottom: 0.4rem; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; }

p { margin-bottom: 1rem; }

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

strong { font-weight: 600; }

/* Code */
code {
  font-family: "SF Mono", "Fira Code", "JetBrains Mono", Menlo, monospace;
  font-size: 0.88em;
  background: var(--code-bg);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem;
  overflow-x: auto;
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

pre code {
  background: none;
  padding: 0;
  font-size: 0.85em;
}

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}

th, td {
  border: 1px solid var(--border);
  padding: 0.6rem 0.8rem;
  text-align: left;
}

th {
  background: var(--code-bg);
  font-weight: 600;
}

tr:nth-child(even) { background: var(--code-bg); }

/* Lists */
ul, ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

li { margin-bottom: 0.3rem; }

/* Blockquotes (used for tips) */
blockquote {
  border-left: 4px solid var(--accent);
  padding: 0.8rem 1.2rem;
  margin: 1.5rem 0;
  background: var(--code-bg);
  border-radius: 0 8px 8px 0;
}

blockquote p { margin-bottom: 0; }

/* Horizontal rule */
hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 3rem 0;
}

/* Warning/Tips */
p > strong:first-child {
  color: #d97706;
}

@media (prefers-color-scheme: dark) {
  p > strong:first-child {
    color: #fbbf24;
  }
}

/* Mobile */
@media (max-width: 900px) {
  #TOC {
    position: static;
    width: 100%;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .content {
    margin-left: 0;
    padding: 2rem 1.5rem;
  }
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--muted); }