Custom font help in project pages / site title

Site URL: https://tulip-wrasse-a4lb.squarespace.com

Hi everyone,

I'm having trouble ensuring all my fonts are consistent, specifically the titles on this page (they should be Circular not Acumin):

https://tulip-wrasse-a4lb.squarespace.com/portfolio

and the next/previous project links at the bottom of each page, for example:

https://tulip-wrasse-a4lb.squarespace.com/portfolio/anthony-burrill

title of the site has defaulted to a serif font, looks ok for me on chrome but not Safari:

https://tulip-wrasse-a4lb.squarespace.com

pw is TPP2020

Thanks in advance!

Q1. Use this code

h1, h2, h3, h4 {
    font-family: 'Circular' !important;
}

Q2. Add to Custom CSS

@media screen and (max-width:767px) {
h2.item-pagination-title {
    display: none;
}
.item-pagination-prev-next {
    display: block !important;
}
}

Q3. Have you declared font-face for 'CircularStd-Medium'  yet?

Thanks so much - perfect! I really appreciate it. 

I haven't declared font-face for 'CircularStd-Medium'  - how do I do that?

Dont worry I've worked it out - thank you!