Cascading Style Sheets
You can use it to customize the appearance of your GnuCash reports and also some elements of its user interface.
- One approach to start using it
- Export the printable/easy/fancy invoice to .html and open it using i.e Firefox -- then inspect the html with its developer tools and modify css until you find a satisfactory result. the custom css can then be inserted into the report option and saved as a custom report. from IRC