a,button {
display: inline-block;
-moz-box-sizing: border-box;
width: 150px;
height: 150px;
vertical-align: middle;
border: 1px solid #000;
text-align: center;
}
a,button {
width: 150px;
height: 150px;
border: 1px solid #000;
text-align: center;
}
a {
display: table;
-moz-box-sizing: border-box;
}
a span, button span {
vertical-align: middle;
text-align: center;
}
a span {
display: table-cell;
}