To use a snippet, simply save it in a CSS file in /.obsidian/snippets/. We recommend editing the CSS file using something like Visual Studio Code or Sublime Text to properly highlight and format it, as invalid CSS will not work.
You can also go into Settings > Apperance, then click on the folder icon next to “CSS Snippets” to open that folder.
After you have saved the .css file for this, click the reload button, and enable the snippet.