Quick CSS is located at the bottom in General Styling tab.
How to add CSS in Enfold?
First, go to Enfold options > Layout Builder and select “Show element options for developers” so that we can assign a custom class name to any element in the theme. Now that we can assign a specific class name to the theme elements we can target them using custom CSS and style the elements the way you want it to look.
Where is quick CSS in WordPress?
Go to Appearance > Theme Settings > Styling. Find the Quick CSS option under the CSS section.