Add styles for high contrast mode to panel - make overlay transparent
Add styles for high contrast mode to panel - make overlay transparent

waldekmastykarz/Office-UI-Fabric,zkoehne/Office-UI-Fabric,OfficeDev/Office-UI-Fabric,waldekmastykarz/Office-UI-Fabric,zkoehne/Office-UI-Fabric,OfficeDev/Office-UI-Fabric