html, body   {
 background-color: #fff
 height: 100%; 
 margin: 0; padding: 0;
 text-align: center; }

#index { 
height: 50%; 
width: 50%;
position: absolute; 
left: 25%; 
top: 25%; 
}

#browers {
margin-top:5%;
}

img.a {
     text-align: center;
     margin-left:10px;
     margin-right:10px;
     border: 0px;
 }