Okay. Just in case. Here is a potential js solution. It will look for the element on the user page only, and change it. According to StackOverflow it will override the !important tag for the cass. This is just an example of changing one class on a page.
<script>
$(document).ready(function() {
if(window.location.href.indexOf("user") > -1) {
$('.at-icon').attr('style','width:16px !important');
}
});
</script>