body{
    margin: 0;
    padding: 0;
    background: #364b63;
}
.center{
 position: absolute;
 top: 50%;
 left: 50%;
 transform: translate(-50%, -50%);
}
.slider{
    background: url(images/img-1.jpg);
    background-size: cover;
    height: 450px;
    width: 800px;
    box-shadow: 0px 5px 8px rbga(0,0,0.3);
    animation: animate 20s infinite;
}
@keyframes animate {
    20% {
        background: url(images/img-2.jpg);
        background-size: cover;
    }
    40% {
        background: url(images/img-3.jpg);
        background-size: cover;
    }
    60% {
        background: url(images/img-4.jpg);
        background-size: cover;
    }
    80% {
        background: url(images/img-5.jpg);
        background-size: cover;
    }
    100% {
        background: url(images/img-1.jpg);
        background-size: cover;
    }
}