An ordinary div

A div with rounded corners

The second div looks so much more fun and professional at the same time!

As it turns out, all you need is one or two extra lines in order to add these rounded corners. See code below:

#my_div {
  border-radius: 15px;
}

If you want more fine-tuning, try the following. The first parameter is the horizontal radius of the rounded corner, the second the vertical.

border-top-left-radius: 10px 5px;
border-bottom-right-radius: 10% 5%;
border-top-right-radius: 10px;

Play around with it and see if you can make something like the following. 😉