Mobile Menu Customizations

Hi all, I'm looking for some help with customizing the mobile menu of my website. On my project pages I am using html to change the logo to a different file in order to change the color. I'd like to accomplish this on my mobile menu as well. Additionally I am looking to change the nav links to a custom font. I have tried a few solutions that I have found on here for that, but haven't had any luck. Any thoughts would be greatly appreciated.

Site PW:
AnoukTuuli

Html that I am using on the project pages to change the logo file for color:

 .header-title-logo img {
    visibility: hidden;
}
.header-title-logo a {
    background-image: url(https://static1.squarespace.com/static/6489f12d5931691c0bdd9856/t/64c0171f3f0c395ef9bf2bc0/1690310431460/Asset+6%40300x.png);
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center center;
}
</style>

Hi,

What is site url?