.btn-3d {
  display: inline-block;
  padding: 12px 30px;
  font-size: 16px;
  font-weight: bold;
  color: #ffffff;
  background-color: #0059b3;   /* solid blue fallback */
  border: 2px solid #00264d;
  border-radius: 6px;
  cursor: pointer;
  text-decoration: none;
  background: linear-gradient(#0059b3, #004080);
  box-shadow: 0 5px 0 #00264d, 0 8px 12px rgba(0,0,0,0.3);
  transition: all 0.2s ease;
}
.btn-3d:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 0 #00264d, 0 12px 18px rgba(0,0,0,0.4);
}
.btn-3d:active {
  transform: translateY(2px);
  box-shadow: 0 3px 0 #00264d, 0 6px 10px rgba(0,0,0,0.3);
}