Header button changes color on Mobile

Site URL: http://www.roamvet.com

Button changes outline color when I open the nav menu on mobile. How do I find this color and make it stay the same? Thanks!

Add this cod into

@media screen and (max-width: 767px) {
    .header .header-actions-action--cta {
        display: block;
        outline: 2px solid #FF0000; /* Change outline color */
    }

    .header .header-actions-action--cta:hover {
        outline-color: #00FF00; /* Change to a different color on hover */
    }
}