What's going on with the default case?
Firstly it has no
break; so I think anything which takes the default branch will trickle down into the
about case. Then you seem to have several redundant lines of code at the bottom of the switch without a case (is that supposed to be the default branch?) Presumably you make the assignment to $page somewhere else in the code?
Just a couple of other observations - why not use single quotes for the $css = '...' - then you don't need to escape every occurrence of double quotes:
$css = '<link href="iestyle.css" rel="stylesheet" type="text/css" />';
is a lot more readable than:
$css="<link href=\"iestyle.css\" rel=\"stylesheet\" type=\"text/css\" />";
Also, I think it's good practice to quote strings, even though in a case statement you aren't forced to. Again it makes the code clearer. Although since you use ternary form for your conditional, I guess clarity isn't a big concern for you.
Edit: I love it when someone else answers between starting and finishing a comment 