.button, .btn {
  background-color: #C9A66B;
  color: white;
  border-radius: 6px;
  padding: 10px 20px;
  transition: background-color 0.3s ease;
}

.button:hover, .btn:hover {
  background-color: #B89056;
}

Albo styl tła strony:

body {
  background-color: #1E1E1E;
  color: #F5F5F5;
}