Before and After pseudo classes used with styled-components

Question

What is the proper way to apply :before and :after pseudo classes to styled components?

I know that you can use

&:hover

Answer 1

This will print the triangle at middle of the div.

const LoginBackground = styled.div`
  & {
    width: 30%;
    height: 75%;
    padding: 0.5em;
    background-color: #f8d05d;
    margin: 0 auto;
    position: relative;
  }
  &:after {
    border-right: solid 20px transparent;
    border-left: solid 20px transparent;
    border-top: solid 20px #f8d05d;
    transform: translateX(-50%);
    position: absolute;
    z-index: -1;
    content: "";
    top: 100%;
    left: 50%;
    height: 0;
    width: 0;
  }
`;