message: Ensure CardHeader can be styled
diff: @@ -29,8 +29,8 @@ const CardHeaderContainer = styled('header')`
  ${noHeadingStyles};
  `;
  -const CardHeader = ({ onClose, children }) => (
  - <CardHeaderContainer>
  +const CardHeader = ({ onClose, children, ...props }) => (
  + <CardHeaderContainer {...props}>
  {children}
  {onClose && <CloseButton onClick={onClose} />}
  </CardHeaderContainer>
  