body 
{
    display: table-cell;
    vertical-align: middle;
}
html, body 
{
   height: 100%;
}
html 
{
    display: table;
    margin: auto;
}
.button, .up, .down, .right, .left {
	float:left;
	width:225px;
	vertical-align: middle;
	border: 5px solid black;
	background-color:blue;
	color:white;
	border-radius: 5px;
	margin-left:5px;
	margin-right:5px;
	text-align:center;
	padding-bottom:25px;
	padding-left:10px;
	padding-right:10px;
}

.height {
	vertical-align: middle;
	margin: 10px;
	display: flex;
	justify-content: center;
}

a:link {
	color: white;	
}

a:visited {
	color: yellow;
}