formatting pass / clarifies CSS syntax

README.md

@@ -9,6 +9,16 @@ Let's take a look at a rather simple example of what CSS does. Go ahead and flip
 <iframe height='265' scrolling='no' title='EWozNm' src='//codepen.io/joemburgess/embed/EWozNm/?height=265&theme-id=0&default-tab=html,result&embed-version=2&editable=true' frameborder='no' allowtransparency='true' allowfullscreen='true' style='width: 100%;'>See the Pen <a href='http://codepen.io/joemburgess/pen/EWozNm/'>EWozNm</a> by Joe Burgess (<a href='http://codepen.io/joemburgess'>@joemburgess</a>) on <a href='http://codepen.io'>CodePen</a>.
 </iframe>
 
+In the CSS, `color` is what we refer to as an property. The `color` property defines what the text color of *all* `h1` HTML elements should be. If we change the value of `color` to `blue`, any `h1` element on the page will turn blue.
+
+**Note**: Normally, every CSS property we define needs to end with a semi-colon (`;`). The one exception is when there is only a single property defined as is the case here. It is good practice to go ahead and add a semi-colon, though: 
+
+```css
+h1 {
+  color: redl;
+}
+```
+
 Now that you understand the basics of CSS, continue onto the next lesson and get a deeper understanding of CSS.
 
 <p class='util--hide'>View <a href='https://learn.co/lessons/styling-with-css-intro'>Styling With Css Intro</a> on Learn.co and start learning to code for free.</p>