You can use all the icons of Font Awesome icons pack (version 4.7: https://fontawesome.com/v4.7.0/icons) or/and those of the Feather icons pack (https://feathericons.com).
Feather Icons Pack
If you want to use an icon from the Feather Icons pack, you can proceed like this:
<i class="cera-icon cera-thumbs-up"></i>
You must first initialize the right icon pack by adding the “cera-icon” class. Then, you just have to choose an icon name via the Feather icons search engine and prefix the name of your chosen icon with “cera-“.
FontAwesome Icons Pack
If you want to use an icon from the Font Awesome pack, you can proceed like this:
<i class="fa fa-star"></i>
You must first initialize the right icon pack by adding the “fa” class. Then, you just have to choose an icon name via the Font Awesome icons search engine and prefix the name of your chosen icon with “fa-“.
Change Icon Color
The “text-primary” class will force the primary color (of your primary button option field).
If you remove this class, the color will simply inherit the color of its parent (ex. icons in menu will inherit from the color of navigation links).
If you want to change the color of an icon, you can proceed like this:
<i class="cera-icon cera-thumbs-up text-primary"></i>
Mix Them All!
You can use all the icons present in these two packs and use them at the same time.