Great. The only other thing you should learn is how to “float” the box in case you don’t want the box to span across the entire width of your content area. For example, let’s say you want to put a box in as an aside, with the rest of the text from the page wrapping around it. You could code something like this:
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc imperdiet risus sit amet risus aliquam viverra. Mauris adipiscing mauris at magna ornare quis accumsan mauris placerat. Fusce vitae elit ut tortor porttitor posuere eget id leo.</p>
<div style="border: 1px solid red; padding: 5px; margin: 5px;clear:both;float:left;width:25px;">
This is some text enclosed in a red box.
</div>
<p>Fusce velit ipsum, egestas sed mollis in, dictum eu ligula. Vivamus ante lectus, hendrerit eget consequat nec, varius sit amet tellus. Phasellus turpis urna, sollicitudin lacinia pretium nec, semper aliquet ligula. Integer sed dolor sit amet ante mollis fermentum a nec nibh. Aliquam vel risus quis quam sodales congue.</p>