Pricing Plugin Continue Button

Hi, I am trying to change the color of the continue button from the green. The Package Block Background in Design Setup doesn’t work. I have tried changing the CSS:
#PACKAGESFORM .btn, .btn:hover {
background: -moz-linear-gradient(center top , #53CC13 0%, #4CBF10 49%, #3FBA00 50%, #3BB000 100%) repeat scroll 0% 0% #53CC13;
color: #FFF;
font-size: 18px;
font-weight: bold;
text-shadow: 0px 1px 0px #2A6000;
text-align: center;
line-height: 30px;
border: 1px solid #43B300;
box-shadow: 1px 2px 2px #319300, 0px 1px 1px rgba(149, 234, 89, 0.48) inset;
border-radius: 5px;
}

But this also didn’t work for me. Can anyone share how I can change this?
Thanks