In the previous chapter, you used a custom color for the Launch screen. You can actually create custom colors and assign them a name in the Assets.xcassets file. This makes them really easy to reuse and ensures consistency in your project. In this section, you will create a custom color and assign it to the collection view cells. Follow these steps to do so:
- Click on the Assets.xcassets folder in the Project navigator and right-click in the clear white space of the document outline, as shown in the following screenshot:

- Choose New Folder from the pop-up menu:

- Change the name of the folder to colors:

If you make a mistake while renaming the folder, remember that you can always select the name and press Return to make it editable.
- Right-click on the colors folder and choose New Color Set:

- Click on the Color Set and click the Attributes inspector...