XF 1.2 Overlapping header

My forum is live since a month now, after importing a VBulletin forum with more than one million posts.

I think most of people can see the forum well but in some cases other people with different screen resolution say that header is overlapping some forum threads.

For example: my screen resolution is 1024x768 and I see my forum right. But for a person wich screen is 1280x1024 header forum is overlapping forum content.

I use the following on my EXTRA.css template:

<xen:if is="@enableResponsive">

@media (max-width:mad:maxResponsiveWideWidth) {
#headerMover #headerProxy {height: 330px !important;}

@media (max-width:mad:maxResponsiveMediumWidth) {
#headerMover #headerProxy {height: 210px !important;}

@media (max-width:mad:maxResponsiveNarrowWidth) {
#headerMover #headerProxy {height: 170px !important;}


How can I solve this?

Do you know if I can check muy forum on several screen configurations? My system just have two differents configuration options.

Thank you!