It's typically a CSS issue, so you could edit the CSS stylesheets (or whatever your WordPress has for CSS, last I recall there were some variables in the admin panel as well as CSS sheets) or you can be a l33t_haxor
and fix it post-page load in JavaScript/jQuery/Whatever your client-side processing is....
document.getElementById('logo').marginTop = "-20px";
A few things to be mindful of though; first, it might not be marginTop, but it will be some CSS property, and what value you set it to will be found by trial & error.
Second, the number of devices and screens ()and screen resolutions) in use today is mind-boggling, larger than ever and doing something like that might not be optimal for all clients. You will probably have to do a lot of experimentation to figure out whether such a fix is applicable to the largest percentage of viewers.