img{
    display: block;
    margin-left: auto;
    margin-right: auto;
}

div#columns {
    position: relative;
    width: 750px;
    top: 20px;
	 margin-left: auto ;
  margin-right: auto ;
}
.button {
    padding:1em;
    position:relative;
}
.button:hover {
  cursor:pointer;
}
.button[disabled]:before {
  content:attr(data-tooltip);
  position:absolute;
  left:75%;
  opacity:0;
  top:0;
  width:auto;
  white-space: nowrap;
  margin-left:1em;
  display:block;
  padding:1em;
  border:1px solid grey;
  background:white;
  transition:all 0.3s;
}
.button[disabled]:hover:before {
  left:100%;
  opacity:1;
}