Change color of post author div/wrapper/box

Hi,

Could you provide css name for the "post author box" (wrapper) and the arrow/pointer associated with it?

I have found the css for the box/wrapper:
.desc-wrapper
and I have successfully edited the background color.

BUT, there is an 'arrow' pointing to the author avatar and I can't edit that element. Could you please tell me the name of this arrow element so that I can edit the color.

Thanx!