html, body {
  font-size: 14px;
  background: url(https://t4.ftcdn.net/jpg/10/84/67/11/360_F_1084671124_2v1OdSlWUZBUGBZrRzUd8EPZW3Scz06F.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}
.pkp_site_name .is_img img {
display: block;
max-height: none;
width: auto;
height: auto;
}