.bg-1 {
    position: relative;
    z-index: 0;
} .bg-1::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: url('../images/bg/bg1.jpg') center no-repeat;
    background-size: cover;
    opacity: 0.15;
    z-index: -1;
}

.bg-2 {
    position: relative;
    z-index: 0;
} .bg-2::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: url('../images/bg/bg2.jpg') center no-repeat;
    background-size: cover;
    opacity: 0.5;
    z-index: -1;
}

.bg-3 {
    position: relative;
    z-index: 0;
} .bg-3::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: url('../images/bg/bg3.jpg') center no-repeat;
    background-size: cover;
    opacity: 0.5;
    z-index: -1;
}

.bg-4 {
    position: relative;
    z-index: 0;
} .bg-4::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: url('../images/bg/bg4.jpg') center no-repeat;
    background-size: cover;
    opacity: 0.3;
    z-index: -1;
}

.bg-5 {
    position: relative;
    z-index: 0;
} .bg-5::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: url('../images/bg/bg5.jpg') center no-repeat;
    background-size: cover;
    opacity: 0.25;
    z-index: -1;
}

.bg-6 {
    position: relative;
    z-index: 0;
} .bg-6::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: url('../images/bg/bg6.jpg') center no-repeat;
    background-size: cover;
    opacity: 0.05;
    z-index: -1;
}