Various sizes, fonts and background colors can be customized for an App - as shown in the Appearance tab below.
In addition, there are 2 menu styles to choose from: Panel and Block (from v220.127.116.11)
The Panel menu style is the original and default menu style - using a tree-style navigation with image icons for each document
To add a Font Awesome icon for a document, use the Font Awesome icon name, including “fa”, in the image field eg fa-bed
Font Awesome icons can also be used in Panel menu style (since Block Menu was introduced) and image URLs can be used in either style.
When switching between Block and Panel menu styles, be sure to reset the default sizes and colors using the “reset” button (top-right).
Resetting is not compulsory but many colors and sizes that look good for Panel style will not suit Block menu style - so it’s a quick way of making a menu look good to start.