.loader {
    position: fixed;
    z-index: 999999;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: rgba(0, 0, 0, 0.7);
    visibility: hidden;
    opacity: 0;
    color:#fff;
    transition: .3s;
}

body.showLoader {
    overflow: hidden;
}

body.showLoader .loader {
    visibility: visible;
    opacity: 1;
}