div.middle{
    margin-left: auto;
    margin-right: auto;
}
div.float-left{
    float:left;
}
div.middle::after{
    content: '';
    clear: both;
    overflow: hidden;
    display: block;
}
span.green{
 color:green;
}
span.grey{
    color: grey;
}
span.blue{
color:blue;
}