Yeah tis a bit off, doesn't flow too well, text too large and not in proportion imo.
Depends what you want to do exactly, is it just the design...
If it were sub domain based you could do this:
$logo = "default";
$sub_domain = explode('.', $_SERVER['HTTP_HOST']);
Is it main domain or sub domain?
You could do this for main domain:
$url = $_SERVER['SERVER_NAME'];
// or $_SERVER['HTTP_HOST'];
Separate names with a comma.