fix w3 validation check

Author: Thierry Boileau

static/css/custom.css

@@ -26,7 +26,3 @@ navigation-logo .a{
 .download-logo {
 	height: 50px;
 }
-
-.highlight {
-	
-}

themes/restlet-framework/layouts/_partials/head/css.html

@@ -14,6 +14,6 @@
 {{- end }}
   <link rel="stylesheet" type="text/css" href="/css/vendor/magnific-popup.css">
   <!-- Custom CSS -->
-  <link rel="stylesheet" href="/css/custom.css" />
-  <link rel="stylesheet" href="/css/vendor/prism.css" />
-  <link rel="stylesheet" href="/css/vendor/component.css" />
+  <link rel="stylesheet" href="/css/custom.css" >
+  <link rel="stylesheet" href="/css/vendor/prism.css" >
+  <link rel="stylesheet" href="/css/vendor/component.css" >