.header .cont .head { background:url(http://amozeshgahkavosh.ir/wp-content/themes/DN/img/head.jpg); }
@media screen and (max-width:768px){
.header .cont .head { background-image:url(https://amozeshgahkavosh.ir/wp-content/themes/DN/img/head-res.jpg);
}
@media screen and (max-width:768px){
.header .cont .head { background-image:url(http://amozeshgahkavosh.ir/wp-content/themes/DN/img/head-res.jpg);
}