How to prevent logo from resizing in fixed header as the page is scrolled down?

The theme I'm working with shrinks the menu and logo while it remains fixed when you scroll down the page. I can't figure out how to stop it from making the logo smaller, I want it to stay the same size.

I think this is the relevant code:

<a class="logo" style="">
<img class="sd-res logo-normal" width="208" height="82" alt="" src="/wp-content/uploads/2016/01/logo-new1.png" style="max-height: 49.7px;">

http://bit.ly/1ZzgElV

via Chebli Mohamed