
((window.gitter = {}).chat = {}).options = {
  room: 'thepracticaldev/1pr',
  useStyles: false
};


function toggleSidebar(){

	sidebar     = document.getElementById("sidebar"),
	mainContent = document.getElementById("main-content");

	if (sidebar.style.display == 'none') {
		sidebar.style.display = 'block';
	} else {
		sidebar.style.display = 'none';
	}
	
}


((window.gitter = {}).chat = {}).options = {
  room: 'thepracticaldev/1pr',
  useStyles: false
};


function toggleSidebar(){
	sidebar     = document.getElementById("sidebar"),
	if (sidebar.style.display == 'none') {
		sidebar.style.display = 'block';
	} else {
		sidebar.style.display = 'none';
	}
}

Update main.js