fix background-code in the index page
fix background-code in the index page

Raynxxx/CUIT-ACM-Website,Z2Y/CUIT-ACM-Website,Z2Y/CUIT-ACM-Website,Z2Y/CUIT-ACM-Website,Z2Y/CUIT-ACM-Website,Raynxxx/CUIT-ACM-Website,Raynxxx/CUIT-ACM-Website,Raynxxx/CUIT-ACM-Website