I wonder if anyone can help me. I'm still learning jQuery and I don't understand why the "left" and "up" buttons are not working. It goes down and right perfectly. Here is my code:

```
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
    $("#dolu").click(function(){
        $("div").animate({
            marginTop:"100px"
        }, "slow");
    });
});
$(document).ready(function(){
    $("#desno").click(function(){
        $("div").animate({
            marginLeft:"100px"
        }, "slow");
    });
});
$(document).ready(function(){
    $("#gore").click(function(){
        $("div").animate({
            marginBottom:"100px"
        }, "slow");
    });
});
$(document).ready(function(){
    $("#levo").click(function(){
        $("div").animate({
            marginRight:"100px"
        }, "slow");
    });
});
</script>
</head>
<body>
<button id="gore">Up</button>
<button id="dolu">Down</button>
<button id="levo">Left</button>
<button id="desno">Right</button><br><br>
<div id="kocka" style="width:50px; height:50px; background-color:#D0D0D0; opacity:1"></div>
</body>
</html>

```