Pure css show/hide withour js (only tested in Chrome)

Pure css show/hide without js with a click event example, a maintained click example and a hover example.

HTML

<input type="radio" id="show" name="group">   
<input type="radio" id="hide" name="group" checked>
<label for="hide" class="hide"></label>
<label for="show" class="show"></label>
<span id="content">Lorem iupsum dolor si amet</span>

CSS

label { position: absolute; top:0; left:0}

input#show, input#hide {
    display:none;
}

span#content {
    display: block;
    -webkit-transition: opacity 1s ease-out;
    transition: opacity 1s ease-out;
    opacity: 0; 
    height: 0;
    font-size: 0;
    overflow: hidden;
}

input#show:checked ~ .show:before {
    content: ""
}
input#show:checked ~ .hide:before {
    content: "Hide"
}

input#hide:checked ~ .hide:before {
    content: ""
}
input#hide:checked ~ .show:before {
    content: "Show"
}
input#show:checked ~ span#content {
    opacity: 1;
    font-size: 100%;
    height: auto;
}
input#hide:checked ~ span#content {
    display: block;
    -webkit-transition: opacity 1s ease-out;
    transition: opacity 1s ease-out;
    opacity: 0; 
    height: 0;
    font-size: 0;
    overflow: hidden;
}
/* extra */
#content, #content1, #content2 {
    float: left;
    margin: 100px auto;
}