App.js

const StyledButton = styled.button`
  display: inline-block;
  border-radius: 3px;
  padding: 0.5rem 0;
  margin: 0.5rem 1rem;
  width: 11rem;
  background: #000;
  color: white;
  border: 2px solid white;

  &:hover {
    opacity: 0.5;
    cursor: pointer;
  }
  @media screen and (min-width: 768px) {
    background: pink;
    color: black;
    border: 1px solid black;
  }
`;