Thanks @giovanni.lignarolo! Yes, for me it worked (partially): I do not see anymore this red background in the ML specialization and therefore the readability was improved clearly.
Many thanks!
However the blue background colors still remained, e.g. in this thread: Any "real world" projects were beginners can help?
as well as this very category on general feedback about our community!
The blue color is not optimal because blue links cannot be read.
Best regards
Christian