Wiki page background suddenly grey

Hi,

wiki pages used to have a nice white background for good
black-on-white contrast, but now the background is grey and everything
looks dim.

It is perhaps not immediately visible, but the <pre> boxes on the Apt
page used to be really visible, now they are just some lightish grey
on some mediumish grey:

https://wiki.postgresql.org/wiki/Apt
https://www.df7cb.de/s/2023-06-12.143740.RVJvp4.png (bottom)

Please consider reverting to white.

Christoph