.row div{
    display: block;
    padding-bottom: 9%;
}

.container-fluid div{
    max-width: 800px;

}

.grey {
    background-color: #333333;
}

.yellow {
    background-color: #FFCC00;
}

.black{
    background-color: #000000;
}

.orange{
    background-color: #FF7F2A;
}

.center{
    margin:0 auto;
}