Elements overflow div

Hi,

I want to add a border to the page in Yii 2. So I have done the following:

<body>

<div style="width:90%;border:1px solid black;margin-left:auto;margin-right:auto;">

</div>

</body>

However, this results in the elements overflowing the div. Please see the screenshot attached.

What could I do to fix this problem?

5975

screenshot.JPG