.scope, .content {
    box-sizing: border-box;
}
.scope {
    position: relative;
    overflow: hidden;
    width: 100%;
}
.ratio1x1 { padding: 50% 0; }
.ratio2x1 { padding: 25% 0; }
.ratio3x1 { padding: 16.5% 0; }

.content {
    width: 100%;
    height: 100%;
    
    background-size: cover;
}

.center {
    background-position: center center;
}
.top {
    background-position: top center;    
}
.bottom {
    background-position: bottom center;    
}
.container {
    position: absolute;
    height: 100%;
    width: 100%;
    top: 0;
}