body, html {
    /*display: grid;
    justify-content: center;*/

    font-family: Arial, sans-serif;
    color: #FFFFFF;
    background-color: #000000;

    background-image: url('chess.png');
    background-repeat: no-repeat;
    background-size: cover;

    overflow: hidden;
    height: 100%;
    /*margin: auto;
    padding: 0;*/
    }

header{
    padding: 50px 50px;
    display: flex;
    justify-content: center;
}

div{
    background-image: none;
    background-color: #000000;
    corner-radius: 20px;
    border-radius: 20px;
    box-shadow: 2px 2px 20px 23px #7fecad;
    display: inline-block;
    /*height: 50%;*/
    padding: 20px;
}

a{
    color: #7fecad;
}