The most customizable aspect of the user interface your application delivers is the one provided by Salesforce through its highly customizable layout editor, which provides the ability to customize standard user interface pages (including those now delivered via the Salesforce1 mobile client) used to list, create, edit, and delete records.
Lightning Experience is the latest user interface experience available for your desktop users. Salesforce Classic or Aloha is the name given to the existing user interface. It's radically different both in appearance and technology. Fortunately, your existing investments in layouts and Visualforce are still compatible. Lightning, however, does bring with it a more component-driven aspect, and, with it, new tools that allow even greater customization of the overall user experience.
Keep in mind...