To activate the Dark Mode in SWPanel, you must first go to the top right corner of your SWPanel, go to the "Settings" icon and click on the "My SWPanel preferences" option.
Once in the "Preferences of my SWPanel", section, you must click on the "Colors" tab. Then, click on the "Enable Dark Mode" button.
Finally, click on Save preferences.
You already have the SWPanel with Dark Mode.