.back1 {
    -webkit-background-size: cover;
    height: 100%;
    background: url(../images/background/back1.jpg) 50% 50% / cover no-repeat fixed;
}


.back2 {
    -webkit-background-size: cover;
    height: 100%;
    background: url(../images/background/back2.jpg) 50% 50% / cover no-repeat fixed;
}
.back3 {
    -webkit-background-size: cover;
    height: 100%;
    background: url(../images/background/back3.jpg) 50% 50% / cover no-repeat fixed;
}
.back4 {
    -webkit-background-size: cover;
    height: 100%;
    background: url(../images/background/back4.jpg) 50% 50% / cover no-repeat fixed;
}
.back5 {
    -webkit-background-size: cover;
    height: 100%;
    background: url(../images/background/back5.jpg) 50% 50% / cover no-repeat fixed;
}

.back6{
     -webkit-background-size: cover;
     height: 100%;
     background: url(../images/background/back6.jpg) 50% 50% / cover no-repeat fixed;
 }