body{
margin: 0 auto;					/*align the header at the center*/
text-align: center;				/*align the header at the center*/
}


div.card
{
width: 15em;					/* width of each container*/
height: 15em;					/* height of each container*/
position: absolute;				/* instructure each container to obey the position absolutely*/
float: left;					/* float all the container so that they overlapped each other*/
left: 38%;						/* align them to the center of the screen */
border: #000 solid 10px;		/* give it a border to make it look nice*/
}

div#box1
{
background-color: #66A666;/*green*/
}
div#box2
{
background-color: #E37373;/*pink*/
}
div#box3
{
background-color: #B2B2B2;/*grey*/
}
div#box4
{
background-color: #A51515;/*red*/
}