<button class="radikalwp-btn-neon-green">شروع بازی<//button>

.radikalwp-btn-neon-green {
  padding: 13px 32px;
  font-size: 16px;
  font-family: inherit;
  color: #4ade80;
  background: #052e16;
  border: 2px solid #4ade80;
  border-radius: 12px;
  cursor: pointer;
  transition: all .3s ease;
  box-shadow: 0 0 12px rgba(74, 222, 128, .45), inset 0 0 10px rgba(74, 222, 128, .12);
}
.radikalwp-btn-neon-green:hover {
  color: #052e16;
  background: #4ade80;
  box-shadow: 0 0 28px rgba(74, 222, 128, .85), 0 0 56px rgba(74, 222, 128, .35);
  text-shadow: none;
}