ThemeProvider (#677)

closes #655

app/components/HelpText/HelpText.js

@@ -1,10 +1,9 @@
 // @flow
 import styled from 'styled-components';
-import { color } from 'shared/styles/constants';
 
 const HelpText = styled.p`
   margin-top: 0;
-  color: ${color.slateDark};
+  color: ${props => props.theme.slateDark};
 `;
 
 export default HelpText;