font size in tooltip in WP-Fullcalendar too small

Hi,
Back in Dec 2020, I asked about how to increase the font size of tooltips in WP-Fullcalendar. Timrv kindly provided me with the follow code:
.ui-tooltip.qtip .ui-tooltip-content {
font-size: 16px !important;
line-height: 1.3 !important;
}
It worked. Now I update EMPro to 2.6.8 which impacts on the WP-Fullcalendar tootips. The above code does not work anymore. Can someone provide me with an update code?

Also the tooltips background color is now white. Can some code be used to change its color?

Thanks