Just to add this seems to only be applied if header-dark class is set - if you disable this in the UI/quark.yaml, and ensure that it also isn't enforced using body_classes in the page frontmatter then these values can be overridden:

https://github.com/getgrav/grav-theme-quark/blob/develop/scss/theme/_header.scss#L21-L36

@mrichar1 , i don't think you can add css class to html / twig templates from a scss file...
but i'm really no scss expert. just using common sense...

Sorry to be unclear - I wasn't meaning that you need to change/override _header.scss - I was highlighting that the !important settings are applied if .header-dark is set, and that this can be enabled either in the theme's quark.yaml/UI OR by adding it to the bg_classes setting in the page frontmatter.

the most important part to is that there is a class called bg-gray applied to an "unrelated" item.

if feels wrong to redefine bg-gray as being white.

and i also think that a css file that is supposed to be extended by the final user should not be marked as !important.

i will have to check if disabling the "header-dark" set has an advantage to me, but the project that "raised" issue is now published and i'm not currently working on it right now.

I also stumbled across this. The bg-grey class should be used and "normal" css styling should be applied to those elements in my opinion.