fixup! Rebranded demo page

Author: felixgirault

site/index.html

@@ -173,7 +173,7 @@ <h3 id="styling" data-example="styling-example">Styling</h3>
 						></iframe>
 					</details>
 
-					<p class="TextHighlight">
+					<p class="Notice Theme--warning">
 						<em>
 							Keep in mind that when changing the styles, you must ensure
 							that the resulting color combinations are contrasting
@@ -199,7 +199,7 @@ <h3>Themes</h3>
 						></iframe>
 					</details>
 
-					<p class="TextHighlight">
+					<p class="Notice Theme--info">
 						<em>
 							Themes are meant to integrate Orejime to specific
 							environments where its interface can't be adapted with CSS
@@ -335,7 +335,7 @@ <h3>Migrating from V2 to V3</h3>
 						version.
 					</p>
 
-					<p class="TextHighlight">
+					<p class="Notice Theme--warning">
 						<em>
 							Be sure to paste an Orejime config and not arbitrary
 							JavaScript code, as it will be evaluated in your browser in