Almost every application I code has themes which either the end user can change or the admin can set or can be changed on the fly. Doing all these things was easy in CakePHP 2.x. With the first alpha release of CakePHP 3.x I was naturally keen to try out how theming worked with V3.
Wrote about using themes in CakePHP 3 at the SANIsoft blog. Themes in CakePHP version 3 are now full fledged plugins. This allows for a lot of flexibility and helps in keeping your code DRY. I have added a step by step example where I use Twitter Bootstrap to theme baked Post views. The steps are simple and have complete code for your use for the layout and index.ctp