We include three examples css files C:\Program Files (x86)\Micro Focus\extend 10.1.0\AcuToWeb\Web\_CSS\examples
I choseThemeFx ....in your gateway.config file you add your themes, In this case I called it Mytheme:
"Mytheme": "C:\\Program Files (x86)\\Micro Focus\\extend 10.1.0\\AcuToWeb\\Web\\_CSS\\examples\\ThemeFX.css"
Then in your url you add the Theme:
Run the program and you'll see a color variation compared to without the theme