.rotated-rectangle {
    -webkit-transform-origin: center;
    -moz-transform-origin: center;
    -ms-transform-origin: center;
    -o-transform-origin: center;
    transform-origin: center;

    -webkit-transform: rotate(90deg);
    -moz-transform: rotate(90deg);
    -ms-transform: rotate(90deg);
    -o-transform: rotate(90deg);
    transform: rotate(90deg);
}