Font size should change when screen size changes

[co-robo]

Other than the coala heading error in issue #23, the other text/heading also are not that responsive.

like in this screenshot, source button shifted downwards when screen size was reduced.
Opened by @yashovardhanagrawal at Gitter

[bharatpurohit97]

@yashovardhanagrawal i guess this issue has been fixed.