How to set up a normal logo in the middle

Hi there,
we have just changed the logo and it looks it is not aligned with menu buttons on some browsers (safari/firefox).
We have been using this code from the previous logo:

@media only screen and (min-width: 800px){
#header .logo {
float: left !important;
margin: 0px 0 0 !important;
overflow: hidden !important;
z-index: 5000 !important;
position: absolute !important;
}

If we delete it or no, in both cases the logo is not aligned.
How can we fix this?

Thanks! :)