How to change default font size 21.5 to 14 in Storyline

Hello everyone,
I do video recording and would like to be able to change the font size in the caption from the default 21.5 to 14 for all the captions in the video without having to do one by one. 

Is there a way to set the font size default in Storyline from 21.5 to 14 for example. 

Thanks for your help,

Sonya