Try adding this CSS to the Custom CSS box.
.banner {
position: relative;
width: 100%;
overflow: auto;
font-size: 18px;
line-height: 24px;
text-align: center;
color: rgba(255,255,255,.6);
text-shadow: 0 0 1px rgba(0,0,0,.05), 0 1px 2px rgba(0,0,0,.3);
background-color: #5b4d3d;
box-shadow: 0 1px 2px rgba(0,0,0,.25);
}
.banner ul {
list-style: none;
width: 300%;
padding: 0;
margin: 0;
}
.banner ul li {
display: block;
float: left;
width: 33%;
padding: 200px 0;
min-height: 200px;
background-position: center top;
background-repeat: no-repeat;
background-size: 100% auto;
box-shadow: inset 0 -3px 6px rgba(0,0,0,.1);
}