Using CSS to change site title font

Hello, on this website I found a post which mostly resolved my issue of not finding a way to change the font of my site’s title and tagline in the Neve theme: https://www.ads-software.com/support/topic/neve-title-and-tagline/

I went to “Additional CSS” and entered the following code:

.nv-title-tagline-wrap .site-title {
font-family: inconsolata !important;
}
.nv-title-tagline-wrap small {
font-family: inconsolata !important;
}

This successfully changed my title font from the default font family to Inconsolata. However, the catch is that I am already using the font family Inconsolata on my website. If I try to use a font family which I don’t already have in use on my website, it won’t work:

.nv-title-tagline-wrap .site-title {
font-family: fira-mono !important;
}
.nv-title-tagline-wrap small {
font-family: fira-mono !important;
}

The above code does not work. Does anyone know what I have to do in order to get a new font working for my site title and tagline? Thank you.

The page I need help with: [log in to see the link]