As much as I want to have all the CSS properties memorized, that isn't a nice thing to do to my brain. Instead I visualize my CSS snippets as a garden that I weed and prune.

My CSS snippets garden used to be a folder of text files which was fine. The key to that way was naming the files so they were easy to scan. Lately I moved to an app called Snippety that's a little more fun to garden in. It's quicker to search, prune, and the name is perfect. It also supports a way to export snippets to a file which is something you should always check before you fill up an app with your notes, thoughts, and ideas.