message: add border around white blocks
diff: @@ -79,7 +79,7 @@ const Index = props => (
  </td>
  {['white', 'gray', 'black'].map((fg, j) => (
  <td key={j}>
  - <Block p={3} mb={2} bg={bg}>
  + <Block p={3} mb={2} bg={bg} border={bg === 'white'}>
  <Text color={fg}>{fg}</Text>
  </Block>
  </td>
  