To try out the new dark theme, you will need to have the latest version of Google Chrome or Mozilla Firefox browser. You will also need to download and install the ‘stylus extension’ to be able to try it out.
Step 2: Next, you need head over to this link and install style.
Step 3: Now, once the installation is complete, open https://web.whatsapp.com/ on your browser. If the process was successful, it will now open with the dark theme.
At any point, you can even disable the dark theme if you don’t want it. Simply click on the extension, and check the box that says “Turn Off All Styles.” This will revert the interface to the original theme.