$(function(){
$("html").css("font-size", $(window).width() >= 750 ? 100 : $(window).width() / 750 * 100 + "px");
$(window).resize(function () {
$("html").css("font-size", $(window).width() >= 750 ? 100 : $(window).width() / 750 * 100 + "px");
});
});