How custom all plugins view for Accessibility ?

Hello everyone ! 

I'm a new beginning Developer. I already use Elgg. But now I would like custom all interface for accessibility (WCAG). I have no idea how to proceed. I don't find HTML DOM. Someone can help me ? 

Thank you Elgg community !

Beginning Developers

Beginning Developers

This space is for newcomers, who wish to build a new plugin or to customize an existing one to their liking