HCL Connections is a customizable product, using the traditional way with " <CNX-CUSTOMIZATION-DIR> " or using customizer.
During this days we are working on an upgrade to version 7 where the whole cnx theme it was supposed to be customized in red even the Invite guest
After some test without the result , because the HCL documentation was not updated (invite application is NOT mentioned even reading version 7.0 doc) we have found the correct path in a css comment ....
/* Fallback content for custom styles. Please create the styling file '<CNX-CUSTOMIZATION-DIR>/invite/stylings/custom.css' to use this feature! */