You didn't provide the js code in the jsfiddle, so as cantera said we can just guess, but ignoring that i'll try to point you out in the right direction.
You will be needing javascript/jq to do this, you might be able to do it using css hovers and maybe -webkit-animation-fill-mode: forwards;
, but nothing i can come up fast enough, bare in mind that hovers are not clicks, except in mobile browsers, so unless somebody comes up with a clever idea for css, i'll give you a simple approach using jq.
Html
<div id="tab-box-container">
<ul id="tab-header">
<li class="class="selected"">Overview</li>
<li>Network</li>
</ul>
<div id="tab-content-container">
<div class="tab-content">
<h3>Tab 1</h3>
<p>
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna aliqua.
</p>
</div>
<div class="tab-content hidden">
<h3>Tab 2</h3>
<p>
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua.
</p>
</div>
</div>
</div>
Js
var tabs = $('#tab-header li');
var tabContent = $('.tab-content');
tabs.click(function(){
var index = tabs.index( this );
tabs.removeClass('active');
$(this).addClass('active');
tabContent.addClass('hidden');
$(tabContent[index]).removeClass('hidden');
});
Now you don't need to use an id for each tab pairing with your tab-content id, you just need to place them in order, the first tab will match with the first tab-content, and so on...
Here is the last jsfiddle http://jsfiddle.net/zDNN9/16/
Good luck =)