.birthday-form {
  margin: 40px 40px;
  min-width: 250px;
  width: 45%;
}

input,
textarea,
button {
  font-size: inherit;
  margin: 15px 0;
  padding: 12px 20px;
  width: 100%;
}

button {
  background-color: teal;
  border: 1px solid black;
  color: white;
  width: 50%;
}

.hidden {
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  height: 1px;
  overflow: hidden;
  position: absolute;
  white-space: nowrap;
  width: 1px;
}