GRAS-1080: Applied responsive styles for the header buttons.
GRAS-1080: Styles for the active tab were added.
Merge branch 'joust' into issues/GRAS-1080-Header-buttons-are-not-responsive
GRAS-1080: responsive navigation bar done.
Merge branch 'issues/GRAS-1080-Header-buttons-are-not-responsive' into joust