Mashup Builder > Mashups > Custom CSS > Custom CSS Editor
  
Custom CSS Editor
The Custom CSS editor is visible when you create or edit a mashup and is only available in Composer.
The key features of the Custom CSS editor are as follows:
Standard CSS: allows you to create standard CSS rules (not enabled for SASS) for mashups and widgets. Rather than target widget ids, you can add custom CSS classes and apply it to widgets that have the CustomClass property.
Linting: allows you to correct the warning and syntax error messages that appear when you add content to the CSS editor.
Autocomplete: allows you to type in the list that appears when you press CONTROL + SPACE. This feature is available when you create a declaration (property or value).
The Custom CSS can be added on a Master mashup, if you share multiple CSS mashups that have the same master. If the CSS is specific to a mashup, add the CSS to the mashup.
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Even if CSS is added to a specific mashup, the CSS rules could impact other elements in the page outside the mashups content.
If an extension mashup is not editable, Custom CSS cannot be added. Consider adding CustomClass values to the widgets in non-editable mashups. These provide extra hooks that you can use to modify the look and feel without changing the mashup.