Opera Browser comes with a new hidden secret color theme. By default, the new color theme is disabled, but you can enable it easily. The new color theme is a green-colored UI theme. In this article, you will learn how to enable this secret theme in your Opera web browser.
Activate Green Color Theme in Opera Browser
Open Opera web browser and type below url in the address bar and press Enter.
opera://flags
It will open the Opera browser Experiments page. Now type color theme in the Search flags text field.
Now select Enabled from the drop-down box to enable the hidden secret green color theme in your Opera web browser.
Now click the Relaunch now button to restart Opera and changes to take effect.
Note: If you want to restore default theme, set the above mentioned value to Default again.