Dear all,
at [1] you can find a new theme package for OpenACS that is based on the W3.CSS framework from W3Schools [2].
It provides a lightweight alternative to Bootstrap and other similar toolkit, with the advantage of requiring a single css file and no javascript (although a siprinkle of javascript was needed for the buttons in the main menu).
Feel free to check it out!
All the best
Antonio
[1] https://github.com/Elettrotecnica/openacs-w3css-theme
[2] https://www.w3schools.com/w3css/