CSS code to apply to MediaWiki:Wikia.css:

.popup-button .popup {
    background-color: #2e2e2e;
    border-radius: 10px;
    width: 0px;
    height: 0px;
    overflow: hidden;
    font-size: 13px;
    opacity: 0;
    color: #EBEBEB;
    margin-left: -200px;
    margin-top: -100px;
    position: absolute;
    z-index: 10;
    transition: opacity 0.5s;
    -moz-transition: opacity 0.5s;
    -webkit-transition: opacity 0.5s;
    -o-transition: opacity 0.5s;
.popup-button:hover .popup {
    width: 215px;
    height: auto;
    opacity: 0.8;
.popup div {
    margin: 10px;
.popup span {
    font-size: 14px;
    font-weight: bold;
.hoverimage img {
    opacity: 0.85;
    filter: alpha(opacity=85);
.hoverimage img:hover {
    opacity: 1.0;
    filter: alpha(opacity=100);

This will create a popup when you hover your cursor over a visible button. Example code shown here:

<div class="popup-button" style="width:150px; position:relative; margin:auto">
<span class="hoverimage">[[File:Example Popup.png|link=Sam Wang Sandbox Wiki|Main page]]</span>
<div class="popup" align="left"><div><span>Example Title</span><br />Example text</div></div></div>

Will produce:

This was originally designed for Isle of Tune Wiki, but also be used on other wikis.