img.center {
position: fixed;
left: 50%;
top: 50%;
}
img#b1 {
width: 600px;
height: 600px; 
margin-left: -300px;
margin-top: -300px;
z-index: 2; }
.b2 {
width: 400px;
height: 400px; 
margin-left: -200px;
margin-top: -200px;
z-index: 3; }
img#b3 {
width: 150px;
height: 150px; 
margin-left: -75px;
margin-top: -75px;
z-index: 4; }
img#b4 {
width: 105px;
height: 105px; 
margin-left: -52px;
margin-top: -52px;
z-index: 5; }
img#a1 {
width: 200px;
height: 167px;
top: 3%;
left: 3%;
position: absolute; }
img#a2 {
width: 200px;
height: 167px;
position: absolute; 
right: 3%;
top: 3%;
}
img#a3 {
width: 200px;
height: 167px;
position: absolute; 
right: 3%;
bottom: 3%;
 }
img#a4 {
width: 200px;
height: 167px;
position: absolute; 
bottom: 3%;
left: 3%;
 }
p#bar {
position: fixed; 
background-color: #cfdfff;
border: maroon 4px double;
height: 9em;
width: 15%;

top: 30%;
bottom: 30%;
z-index: 5;
}

p#bar2 {
position: fixed; 
background-color: #cfdfff;
border: maroon 4px double;
width: 15%;
height: 9em;
top: 30%;
bottom: 30%;
z-index: 5;
}

a#al1 {
position: absolute;
top: 25%;
left: 50%;
margin-left: -7em;
z-index: 4;
}

a#al2 {
position: absolute;
left: 30%;
top: 65%;
z-index: 4;
}

a#al3 {
position: absolute;
left: 60%;
top: 65%;
z-index: 4;
}