[css-cascade] Syntax highlighting.

Author: tabatkins

css-cascade/Overview.bs

@@ -71,7 +71,7 @@ Importing Style Sheets: the ''@import'' rule</h2>
 		and illustrate both ''@import'' syntaxes
 		(one with ''url()'' and one with a bare string):
 
-		<pre>
+		<pre class='lang-css'>
 		@import "mystyle.css";
 		@import url("mystyle.css");
 		</pre>
@@ -175,19 +175,20 @@ Shorthand Properties</h2>
 		is a <a>shorthand</a> property for setting <a property>font-style</a>, <a property>font-variant</a>, <a property>font-weight</a>, 'font-size', 'line-height', and <a property>font-family</a> all at once.
 		The multiple declarations of this example:
 
-		<pre>
-h1 {
-	font-weight: bold;
-	font-size: 12pt;
-	line-height: 14pt;
-	font-family: Helvetica;
-	font-variant: normal;
-	font-style: normal;
-}</pre>
+		<pre class='lang-css'>
+		h1 {
+			font-weight: bold;
+			font-size: 12pt;
+			line-height: 14pt;
+			font-family: Helvetica;
+			font-variant: normal;
+			font-style: normal;
+		}
+		</pre>
 
 		can therefore be rewritten as
 
-		<pre>h1 { font: bold 12pt/14pt Helvetica }</pre>
+		<pre class='lang-css'>h1 { font: bold 12pt/14pt Helvetica }</pre>
 
 		As more 'font' <a>sub-properties</a> are introduced into CSS,
 		the shorthand declaration resets those to their initial values as well.
@@ -742,7 +743,7 @@ Important Declarations: the ''!important'' annotation</h3>
 	in its value are the delimiter token ''!'' followed by the identifier token ''important''.
 
 	<div class='example'>
-		<pre>[hidden] { display: none !important; }</pre>
+		<pre class='lang-css'>[hidden] { display: none !important; }</pre>
 	</div>
 
 	An <a>important</a> declaration takes precedence over a normal declaration.
@@ -770,7 +771,7 @@ Important Declarations: the ''!important'' annotation</h3>
 		Also, the third author rule will lose to the second author rule since the second declaration is ''!important''.
 		This shows that ''!important'' declarations have a function also within author style sheets.
 
-		<pre>
+		<pre class='lang-css'>
 		/* From the user's style sheet */
 		p { text-indent: 1em !important }
 		p { font-style: italic !important }