message: add fontWeights to theme
diff: @@ -47,6 +47,12 @@ const theme = {
  ]),
  mono: fontStack(['SFMono-Regular', 'Consolas', 'Liberation Mono', 'Menlo', 'Courier', 'monospace'])
  },
  + fontWeights: {
  + light: 300,
  + normal: 400,
  + semibold: 500,
  + bold: 600
  + },
  colors,
  borders: [0, '1px solid'],
  fontSizes,
  