form button.loading .message_send_satatus::after {
  content: "";
  animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
  0% {
    content: "";
  }
  25% {
    content: ".";
  }
  50% {
    content: "..";
  }
  75% {
    content: "...";
  }
  100% {
    content: "";
  }
}