Style /tag/…

Hi,

I’m having some trouble styling a specific page, normally this link is hidden on my site: http://www.example.com/tag/anyTag, but users can still access it thru google.

Initially it was not styled; because users cannot see it; but now I want to style it anyway.
But I can’t seem to find how I can style that page.

It’s basically a list of al posts from that tag