a.btn {
  text-decoration: none;
}
.btn {
  color: white !important;
  border-radius: .5rem;
  padding: .375rem 1.75rem;
  font-size: 1.1rem;
  cursor: pointer;
  transition: filter .3s ease-out;
}
.btn:disabled {
  cursor: not-allowed;
  filter: grayscale(100%);
}
.btn:active {
  color: white !important;
}
.btn:hover {
  filter: brightness(1.2);
}

button.btn {
  border: none;
}

.btn-primary {
  background-color: #318ffb;
}
.btn-ok {
  background-color: #47c74c;
}
.btn-gray {
  background-color: #d9d9d9;
}

.btn-circle {
  border-radius: 50%;
  width: 40px;
  height: 40px;
  padding: 8px;
  box-shadow: 1px 1px 4px 0 #0003;
}