Background

background-attachment, background-position, background-repeat, background-size

For responsive

add -sm, -md, -lg or -xl to class name, for example:

<div class="bgas bgaf-md"></div>

.bn {
    background: none;
}
.bgct {
    background-color: transparent;
}

background-attachment

.bgaf {
    background-attachment: fixed;
}
.bgal {
    background-attachment: local;
}
.bgas {
    background-attachment: scroll;
}

background-position

.bgpt {
    background-position: top;
}
.bgpb {
    background-position: bottom;
}
.bgpc {
    background-position: center;
}
.bgpl {
    background-position: left;
}
.bgpr {
    background-position: right;
}
.bgplb {
    background-position: left bottom;
}
.bgplt {
    background-position: left top;
}
.bgprt {
    background-position: right top;
}
.bgprb {
    background-position: right bottom;
}

background-repeat

.bgrr {
    background-repeat: repeat;
}
.bgrnr {
    background-repeat: no-repeat;
}
.bgrrx {
    background-repeat: repeat-x;
}
.bgrry {
    background-repeat: repeat-y;
}

background-size

.bgs-cover {
    background-size: cover;
}
.bgs-contain {
    background-size: contain;
}
.bgs-auto {
    background-size: auto;
}