<input class="input" type="radio" name="tabs" id="tab-1" />
<input class="input" type="radio" name="tabs" id="tab-2" />
<div class="content content-1">content 1</div>
<div class="content content-2">content 2</div>
.content { display: none; }
#tab-1:checked ~ .content-1 {display: block;}
#tab-2:checked ~ .content-2 {display: block;}