index.html

<link rel="stylesheet" type="text/css" href="http://www.(SITEWEB).com/sketchfab.css"> 
<div class="holder">
  <iframe width="100%" height="100%" src="https://sketchfab.com/models/375ae80dc7e34b229cc9739b1ce92e2b/embed?autostart=1&autospin=0.2&controls=0&transparent=1&ui_watermark=0&stop_button=0&desc_button=0" frameborder="0" allowfullscreen mozallowfullscreen="true" webkitallowfullscreen="true" onmousewheel=""></iframe>
     <a class="bouton" href="#blank">
          <div class="bar">   
                <div class="info-bulle">
                    <p>Powered by <b>Sketchfab</b></p>
                </div>
          </div>
      </a>
</div>

 

sketchfab.css

.holder{
    width: 400px;
    height:300px;
    position:relative;
}
.frame{
    width: 100%;
    height:100%;
    
}
.bar{
    position:absolute;
    bottom:0;
    left:0;
    width:20%;
    height:20%;
    background: transparent;
    }
    
  /*---- Bouton > info-bulle ----*/

a.bouton div.info-bulle

{

    visibility: hidden;

    opacity: 0;

    position: absolute; /* important */

    top: -100px;

    left: 0;

    transition: 0.3s ease-out;

    -webkit-transition: 0.3s ease-out;

}
a.bouton:hover div.info-bulle

{

    visibility: visible;

    opacity: 1;

    top: -50px;

    transition: 0.6s ease-out;

    -webkit-transition: 0.6s ease-out;

}
div.info-bulle

{

    width: 100%;

    padding: 0px;

    margin: 0 auto;

    background: #f5f5f5;

    border-radius: 3px;

    box-shadow: 3px 5px 10px rgba(0,0,0,0.3);

}
div.info-bulle p

{
    font-family: 'Open Sans', sans-serif;
    color: #555;
    font-size: 60%;

    padding: 10px 5px;

    margin: 0;

    text-align: center;

    text-shadow: 1px 1px 0px rgba(255,255,255,0.5);

}