comments backround and widgets problems

Hi I have two more problems:

My site is efepefoto.com

I can´t find how to remove the white content box of the blog comments (screenshot1)

the archive and categories widget are working different on the sidebar from the footer
I can read them in the footer but it is impossible in the sidebar (screnshot 2 & 3)
Is it possible to make the text color black in both of them?

Thank you very much
Facundo