fix: replaced show and hide class hidden with attribute hidden

Author: frankpagan

docs/index.html

@@ -100,7 +100,7 @@ <h2 class="padding:5px_0px">Demo</h2>
 						<div class="container svColumn overflow:hidden card position:relative border-radius:2px width:auto height:100%" id="sandbox">
 							<div class="font-size:20px position:absolute top:10px right:10px opacity:0.6">
 								<a class="margin-right:10px" id="code" show="#preview" hide="#code, #view"><i class="far fa-eye"></i></a>
-								<a class="margin-right:10px hidden" id="preview" show="#code, #view" hide="#preview"><i class="fas fa-code"></i></a>
+								<a class="margin-right:10px" id="preview" show="#code, #view" hide="#preview" hidden><i class="fas fa-code"></i></a>
 								<a class="margin-right:5px" fullscreen target="#playground"><i class="fas fa-expand"></i></a>
 							</div>
 							<div class="svRow">