message: More configurable HR
diff: import styled from 'styled-components';
  +import { themeGet, space } from 'styled-system';
  +
  +import { preset } from 'react/styles/functions';
  export default styled.hr`
  - margin: 1em auto;
  + ${preset(space, { my: 6 })}
  height: 1px;
  border: none;
  - background-color: ${x => `
  - ${!x.invisible && (x.color || x.theme.colors.gray.regular)}
  - `};
  + background-color: ${(props) => {
  + if (props.invisible) return 'transparent';
  + return themeGet(`colors.${props.color}`, props.theme.colors.gray.regular)(props);
  + }}
  `;
  