HTML
<div class="close-orange"></div>
CSS
.close-orange {
height: 100px;
width: 100px;
background-color: #FA6900;
border-radius: 5px;
}
.close-orange:before,.close-orange:after{
content:'';
position:absolute;
width: 50px;
height: 4px;
background-color:white;
border-radius:2px;
top: 55px;
}
.close-orange:before{
-webkit-transform:rotate(45deg);
-moz-transform:rotate(45deg);
transform:rotate(45deg);
left: 32.5px;
}
.close-orange:after{
-webkit-transform:rotate(-45deg);
-moz-transform:rotate(-45deg);
transform:rotate(-45deg);
left: 32.5px;
}