.invalid-feedback {
  height: 0;
  opacity: 0;
  overflow: hidden;
  transition: opacity 0.3s ease, height 0.3s ease;
  color: #ff6f00;
  font-size: 15px;
  margin-top: 5px;
  line-height: 1.4;
  min-height: 20px;
}

.was-validated input:invalid ~ .invalid-feedback,
.was-validated select:invalid ~ .invalid-feedback,
.was-validated textarea:invalid ~ .invalid-feedback {
  display: block;
  opacity: 1;
  height: auto;
}