Add custom styles to TinyMCE on MODx

1. Login to MODx admin page

2. Select Tools -> Configuration -> Interface & Features

3. on ‘Path to CSS file’, enter your css path (e.g. http://YOUR_DOMAIN/web_assets/css/editor.css)

4. on ‘CSS selectors’, enter a list of selectors in this format: displayName=selectorName;displayName2=selectorName2

5. Click ‘Save’

6. Create the css file you specified in step 3

7. Add the new styles to your template css file