Sage CRM 2021 R2 has added a new feature that allows for the easy override of the current theme.  This is a CSS file that is designed for Sage CRM 2021 R2 modelled on Sage Accounting.

1. On a Sage CRM server, open the following location:
<Sage CRM installation folder>\WWWRoot\Themes\custom
where <Sage CRM installation folder> is the folder you specified when installing Sage CRM. By
default, this is %ProgramFiles(x86)%\Sage\CRM\CRM.

2. Copy the custom .css file provided here to that folder.
3. Open IIS Manager and recycle the CRM App Pool to apply your customizations.
4. Clear browser cache on each client computer to display CSS customizations correctly.