anchor.diff:  
   .navbar {
     margin: 0px;
  +}
  +
  +.navbar-nav {
  +  float: none;
  +  text-align: center;
   }
   
   .nav-bg {
  
positive.code:    }
  }
  
  .nav-item {
    margin: 10px;
    color: #000;
  
negative.code: }
  
  .footer_copyright {
    text-align: center;
  }
  
  .footer_nav {
  