Also they were black and white prior. After upgrading to 11.2.10, all icons become colored. Once I edit the icon, I pick one from the new menus of foundation, font awesome etc… they go back to black and white. Is that by design? 

Is there any documentation on how to use the new icon in Millau? How do I make it larger or reference it in custom css etc.?

Are some of these font awesome? Also what are you upgrading from? Some of the icons do not remain after upgrading past a certain point. 

Hi Jili, this can happen if you switch from one theme to another, because unfortunately not all icons translate from one theme to the next. Please find more information here:
https://docs.skuid.com/latest/en/skuid/themes/#missing-icons

It is possible to add custom CSS if you edit your own custom theme, please click CSS, the last list item on the left in the screenshot:
https://docs.skuid.com/v11.2.11/en/skuid/themes/theme-composer.html#theme-composer-ui