Responsive design and internet explorer

Responsive design and internet explorer

I'm using html5 template with responsive layout and it works just fine (in
all major browsers).
I'm using wide, 728px ad (google adsense) in the header, and I would like
to hide it, when viewport width is less than 728px. So I modified the css
file - added
@media screen and (max-width: 728px) {
.responsiveBanner {
display:none;
}
}
to the end of file. Everything works perfect in firefox and chrome. But
IE10 doesn't hide the banner, when changing the window width.
modified code:
@media screen and (max-width: 728px) {
.responsiveBanner {
display:none;
}
body {
background:yellow;
}
}
also doesn't hide the banner in IE, however, the background change is
applied...
Do you have ayn idea, why IE doesn't hide the banner?
Thanks