Add a short CSS class to an HTML Web page to use animated and stationary GIF images as the page's background.

One way to add a background photo to any custom Tumblr theme is to embed a simple CSS tag at the right location in the theme's HTML code.

To use custom CSS in Obsidian, go to Settings > Appearance, scroll down to CSS snippets, enable it, and then place your .css files in the snippets folder that appears. Obsidian will automatically ...