.verticalTableHeader {
    text-align:center;
    white-space:nowrap;
    transform-origin:50% 50%;
    transform: rotate(90deg);

}
.verticalTableHeader:before {
    content:'';
    padding-top:110%;/* takes width as reference, + 10% for faking some extra padding */
    display:inline-block;
    vertical-align:middle;
}