Nit: Fix invalid css in example

README.md

@@ -2277,7 +2277,7 @@ declarations.
 > For example, see what happens when you paste in the following CSS code:
 > ```css
 > .site-banner {
-> display: relative;
+> position: relative;
 > padding-left: 10px;
 > padding-top: 5%;
 > animation: slide-in 3s linear 1s infinite;