Theme Customization

Customize your blog’s appearance with CSS, HTML headers/footers, and ad placements. You can edit these settings in Dashboard > Settings > Theme, or via the Blogs API.

Default Theme

Postlark’s default theme includes:

Fluid typography (responsive font sizes)
Automatic dark mode (prefers-color-scheme)
Code block syntax highlighting with copy button
Reading progress bar
Skip-to-content link (accessibility)
Responsive images

Custom CSS

You can edit CSS in Dashboard > Settings > Theme > Custom CSS, or via the API:

curl -X PUT https://api.postlark.ai/v1/blogs/BLOG_ID \
  -H "Authorization: Bearer pk_live_xxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "theme_config": {
      "customCss": "body { font-family: Georgia, serif; } h1 { color: #1a1a2e; }"
    }
  }'

Add custom navigation or footer content via Dashboard > Settings > Theme, or via the API:

{
  "theme_config": {
    "headerHtml": "<nav><a href='/'>Home</a> | <a href='/about'>About</a></nav>",
    "footerHtml": "<footer>&copy; 2026 My Blog</footer>"
  }
}

Ad Code

Insert ad network code (e.g., Google AdSense) via Dashboard > Settings > Theme > Ad Code, or via the API:

{
  "theme_config": {
    "adCode": "<ins class='adsbygoogle' data-ad-client='ca-pub-xxx'></ins>"
  }
}

The ad code is rendered between the post content and comments section.

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