It looks like it’s coming from the css you added on line 2193. You have position: absolute
which is causing it to overlap.
Once you remove that line it should fix it. Make sure and click your Reload button on your browser once you make the edit so the changes appear instantly.
.lesson-sidebar {
position: absolute;
margin-top: 20px;
width: 350px;
}
Here’s what it will look like once you make that adjustment – http://i.imgur.com/fiqkulf.png
Let me know if that works.