#preloader {
    width: 100%;
    height: 100vh;
    overflow: hidden;
    position: fixed;
    z-index: 9999999;
}

#preloader:after, #preloader:before {
    content: '';
    position: fixed;
    left: 0;
    height: 50%;
    width: 100%;
    background: #252531;
    -webkit-transition-timing-function: cubic-bezier(0.19, 1, 0.22, 1);
    -o-transition-timing-function: cubic-bezier(0.19, 1, 0.22, 1);
    transition-timing-function: cubic-bezier(0.19, 1, 0.22, 1);
}

#preloader:before {
    top: 0;
}

#preloader:after {
    bottom: 0;
}

#preloader.isdone {
    visibility: hidden;
    -webkit-transition-delay: 1.5s;
    -o-transition-delay: 1.5s;
    transition-delay: 1.5s;
}

#preloader.isdone:after, #preloader.isdone:before {
    height: 0;
    -webkit-transition: all 0.7s cubic-bezier(1, 0, 0.55, 1);
    -o-transition: all 0.7s cubic-bezier(1, 0, 0.55, 1);
    transition: all 0.7s cubic-bezier(1, 0, 0.55, 1);
    -webkit-transition-delay: 1s;
    -o-transition-delay: 1s;
    transition-delay: 1s;
}