How to change font size in tabber

How to change font size in tabber

Hi,

I would like to change the font size of the title in tabber. I have found Slider font customization section in the Album -> Customize layout, but there only Title font and Description font size can be changed.
However I would like to change the font size of the Tabber title.
Could you please give me hint where can I find it? If it is possible only in CSS, please let me know where can I find the font size parameter for Tabber title.

Thank you in advance.