Submodule 4.3: Navigation bar
                                    Các yêu cầu hoàn thành
                                    
            
                    
                                
            
                        
                                    Xem
                                
                    Create a Navigation bar
Through the previous sections we have study the necessary features for creating navigation bar.
Now it is time to construct your own navigation bar. Follow the instructions of the "Assignment: CSS II".
For more information: https://www.w3schools.com/css/css_navbar.asp