.tooltip-inner {
    background-color: #000 !important;
    /*!important is not necessary if you place custom.css at the end of your css calls. For the purpose of this demo, it seems to be required in SO snippet*/
    color: #fff;
}

.tooltip.top .tooltip-arrow {
    border-top-color: #00acd6;
}

.tooltip.right .tooltip-arrow {
    border-right-color: #00acd6;
}

.tooltip.bottom .tooltip-arrow {
    border-bottom-color: #00acd6;
}

.tooltip.left .tooltip-arrow {
    border-left-color: #00acd6;
}