react-photo-view/src/components/Backdrop.tsx

import styled from 'styled-components';

const Backdrop = styled.div`
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.6);
  z-index: -1;
`;

export default Backdrop;