Fix header on mobile. Fixed #142
Fix header on mobile. Fixed #142

gdg-eskisehir/wtm17,GDG-Nantes/devfest2017,GDGJKUAT/DevFestThikaRd2016,gdg-eskisehir/wtm17,GDGJKUAT/DevFestThikaRd2016,GDGYangon/gdg-yangon-devfest-2015-website,GDG-Ukraine/hoverboard,GDG-Ukraine/hoverboard,GDGYangon/gdg-yangon-devfest-2015-website,GDGKoreaCampus/homepage,GDG-Nantes/devfest2017,GDGKoreaCampus/homepage