button in slider

I have tried this ins a text element

Button Code

Request Data Capture

CSS Code

.btn {
  -webkit-border-radius: 10;
  -moz-border-radius: 10;
  border-radius: 10px;
  font-family: Arial;
  color: #ffffff;
  font-size: 18px;
  background: #20242d;
  padding: 10px 10px 10px 10px;
  text-decoration: none;
}

.btn:hover {
  background: #fc4605;
  text-decoration: none;
}

button appears but doesnt take the css

so far got this to kind of work by changing CSS to below but still cant find a way to change color when mouse hovers

-webkit-border-radius: 10;
  -moz-border-radius: 10;
  border-radius: 10px;
  font-family: Arial;
  color: #ffffff;
  font-size: 18px;
  background: #20242d;
 padding: 10px 10px 10px 10px;
  text-decoration: none;

can this be done? we also want to make it so on mobile site it resizes text and images so they dont look tiny. we would pay you to get this working lets say a donation of ￡300