.main_box{
    background-size: cover;}
@media screen and (min-width: 2050px) and (max-width: 2500px) {
.page-nav{
margin-top: 5%;}

}

@media screen and (min-width: 2051px) and (max-width: 3300px) {
.page-nav{
margin-top: 10%;}

}

@media screen and (min-width: 3301px) and (max-width: 4790px) {
.page-nav{
margin-top: 15%;}

}
@media screen and (min-width: 4791px) and (max-width: 5500px) {
.page-nav{
margin-top: 20%;}

}
/*css*/
.imgbed{
    position: relative;
    display: block;
    height: 0;
    width: 100%;
    padding-top: 0%;}
.imgbed img{
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;}