.buttons{
    position:absolute;
    bottom:10px;          /* controls height above banner */
    left:50%;
    transform:translateX(-50%);
    z-index:3;            /* ABOVE banner */
}

button{
    background:black;
    color:white;
    border:1px solid white;
    padding:6px 14px;
    margin:5px;
    cursor:pointer;
}

button:hover{
    background:white;
    color:black;
}