Change One Navigation Element's Style

Site URL: https://porpoise-poodle-8hg6.squarespace.com/

Hello, I'm looking to put a button around one of my navigation elements. I want the button to look identical to the one shown for the phone number in the navigation bar. The element I'd like to encapsulate with a button is the "Book Now" element.

Thanks for your help!

Hi. What is access password?

access password = hello

Add to Home > Design > Custom CSS

.header-nav-item [href*="/book.pocketsuite"] {
    font-family: pragmatica-extended;
    font-weight: 700;
    font-style: normal;
    letter-spacing: .05em;
    text-transform: none;
    line-height: 1.2em;
    color: #000 !important;
    background: #fff;
    border-radius: 300px;
    padding: 10px 20px !important;
}
nav.header-nav-list {
    align-items: center;
}