<button class="radikalwp-btn-wave"><span>سفر کن<//span><//button>

.radikalwp-btn-wave {
  position: relative;
  padding: 13px 34px;
  font-family: inherit;
  font-size: 16px;
  font-weight: 700;
  color: #0369a1;
  background: #f0f9ff;
  border: 2px solid #0ea5e9;
  border-radius: 999px;
  cursor: pointer;
  overflow: hidden;
  z-index: 1;
}
.radikalwp-btn-wave span { position: relative; z-index: 2; transition: color .3s ease .1s; }
.radikalwp-btn-wave::before {
  content: '';
  position: absolute;
  bottom: -100%;
  right: 0;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 30% 70%, #38bdf8 25%, #0ea5e9 75%);
  border-radius: 42%;
  transition: bottom .6s ease;
  z-index: 1;
}
.radikalwp-btn-wave:hover::before { bottom: -40%; }
.radikalwp-btn-wave:hover span { color: #fff; }