Newsletter Text Button

Hi,

I was wondering how I can change the text to white on hover, 

I have applied the hover color but it doesnt seem to work?

/Newsletter button colour 
#block-yui_3_17_2_1_1722894288272_55797
.newsletter-form-button {

color: #a38a5b !important;

border-radius: 50px !important;

transition: all ease-in-out 700ms !important;

-webkit-transition: all ease-in-out 700ms !important;

-moz-transition: all ease-in-out 700ms !important;

background-size: 100% 200%;

background-color: transparent !important;

background-image: linear-gradient(to bottom, rgba(0,0,0,0) 50%, #719bb3
  50%) !important;

}

.newsletter-form-button:hover {

color: #ffffff !important;

background-position: 0 100% !important;

}

Can you share link to this page?