Trouble recoloring text for single nav menu link

Hey guys,

Hoping someone might be able to help me.

I have created a nav menu in the global header and added a button to one of the links with the following code:
.menu-cta a {
background-color: #039572;
padding: 15px 25px !important;
border-radius: 25px;
text-transform: uppercase;
color: #ffffff !important;
text-align: center;

The problem is the color part of the code isn't working. When I load the website to check, it goes white for like half a second and changes black like the rest of the menu links. I want the text within the button to be white but having trouble figuring it out. Any advice is greatly appreciated!