Header tweaks (Jupiter theme)

Hi, everyone! First of all, congrats for the huge community.

I am faced with the following problem. Using the Jupiter theme, I want to get a header with Section 1, Section 2, Section 3, Section 4 as clickable fields.

Section 1 and 2 have the same font
Section 3 must have a different font than the rest
Section 4 must be in a rounded box (like a button), with a distinguishable background color and bolded

Can someone please tell me how to get this running, I’ve looked in the header.php file in my /wp directory, did not find anything relevant to change and to proceed further.

Thanks in advance for your help!