Adjust the riht sidebar to fit ads

Hi folks,

i′m new to wordpress and set up a website with the parabola theme.

I have an amazon ad on the right sidebar implemented, but the sidebar doesn′t fit the ad.

So, i thought I could use the custom.css setting in parabola in order to resize the sidebar. Could you please tell me how it should look like ?

The size of the ad is width 188 px height 406 px
The sidebar′s id is “text-13”

I really need help for this issue ?? Thanks in advice

My website: vr-town.com