Help me please

Question

i have created a dropdn menu, when a user click a icon..here is ts jquery

$("#icon").click(function(){
$("nav>ul").children().slideToggle(500);

/*
when a icon is clicked, the element below the drop down( i.e video), moves down, its margin-top changes from 5px to 50px as shown below*/

$("video").css("margin-top","50px");
});

the problem is when i click the icon again, to slide up the dropdown menu, the video element stays in the margin-top of 50px, i want it to go back to 5px...how ts done?