I present you in exclusivity a dark theme for the code editor based on the WesBos Cobalt2 theme. (https://github.com/wesbos/cobalt2)
I find that the colors of the theme help to highlight the elements of the language. Since I've been using it, I've had a hard time coming back to a light theme.
Here is a screenshot of a method that contains all the elements of the 4D language.
To install the theme, simply modify the file "4D Preferences v17.4DPreferences" or v15, v16. Be careful, versions less than 17 do not have all the same features. The file is located at this location
Windows 7 and higher: {disk}\Users\{UserName}\AppData\Roaming\4D\
macOS: {disk}:Users:{UserName}:Library:Application Support:4D:
Here is a link to download the file containing the preferences of the Cobalt2 theme for 4D