#questionForm {
  transition: all 0.3s ease;
}

#submitBtn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.form-check-label {
  user-select: none;
}

.card {
  border: none;
  border-radius: 15px;
}

.spinner-border {
  vertical-align: middle;
  margin-right: 0.5rem;
}

/* Оформление ошибок формы */
.is-invalid {
  border-color: #dc3545 !important;
}
.invalid-feedback {
  display: none;
  color: #dc3545;
  font-size: 0.875em;
}
.is-invalid ~ .invalid-feedback {
  display: block;
}