Hi there,
go to Customizer > Additional CSS:
/* navigation contact button */
.main-navigation:not(.slideout-navigation) .main-nav li.nav-button a {
color: #ffffff;
background-color: #8eb2a6;
line-height: 44px;
/* button height */
padding: 0px 22px;
/* space inside button */
margin-top: 4px;
/* adjust to horizontally align with other menu items */
border-radius: 40px;
margin-left: 22px;
/* space to the left of button */
transition: all 0.4s ease 0s;
}
.main-navigation:not(.slideout-navigation) .main-nav li.nav-button a:hover {
background-color: rgba(142, 178, 166, 0.9);
color: #ffffff;
transition: all 0.4s ease 0s;
}
Change the 2 background-color
properties.