Change promo text

Hallo guys, first of all thank you very much for a wonderful theme and great support.

I have an issue regarding the promo text and cannot find a solution.
Would like to resize the promo text and have it in lowercase, but as soon as I put some code in de [fruitful_dbox] of the home page the result I get is that the text is resized and left aligned (which is not my wish). Could you be so kind to let me know which code I have to put and where?
On a same question of some time ago it was suggested to change code in functions.php and in style.css (line 574) but with me it did not work.

Thank you very much in advance!