body, html {
    height: 100%;
    margin: 0;
    background-color: black;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    display: flex;
    align-items: center;
    justify-content: center;
}

.shadow-gif {
    height: 278px;
    width: 500px;
    background: url(../img/marvin.gif);
    box-shadow: inset 0px 0px 5px 5px rgba(0,0,0,1);
}