If Calibre is set to dark mode, when viewing recent books, the boilerplate is invisible.

[rtonsing]

I believe the issue is the CSS:
#pg-header div, #pg-footer div {all: initial;}

I tried unzipping an epub, commenting out "all: initial;", and re-zipping. It did seem to fix the issue.

[eshellman]

it's not a problem anywhere else. The all: initial is there to give the boilerplate uniform appearance, overriding inappropriate styling from PPers who never anticipated that our boilerplate would need to change. IIRC, all: inherit was better, possibly fixing this, but was not yet REC. I'll leave this open so we remember to revisit when the relevant spec becomes REC

[rtonsing]

OK