The default color of After Effects might not suit you, for example, I really hate blue and want to change it to orange. Or maybe you do like blue but want to darken or lighten it, here’s how to do it.
Open up After Effects and press (Ctrl + F12), this will open up the console. Press the dropdown on the panel and click Debug Database View. Set Enable_Theme_Colorizing to “true”.
Go into Preferences > Appearance, and now you can change the colour to whatever you want.