Seeing as you're already relying on JavaScript for your menu, you could add a class to the <body> using JavaScript code based on the userAgent string:
JavaScript
if (navigator.userAgent.indexOf("MSIE 10") > -1) {
document.body.classList.add("ie10");
}
..and then target Internet Explorer 10 in your CSS
CSS
/*IE 10 only */
.ie10 .myClass {
margin-top: 1px;
}
