problem with bootstrap

[tim99-1977]

Hi,
it seems to be a optical problem when using with bootstrap (and bootswatch in my case).
the bootstrap.css sets a general background-color to all tables and then it looks like in the screenshot, somehow it doesn't paint some borders.

i tried to set "background-color:transparent" for all calendar tables, but then the colored cells have no borders, like this (look at the green cells):

has someone an idea to get around that? :)