If you’re using Windows, you can switch to Dark Mode by going to Settings and then selecting “Personalization”. Select “Colors” and then under “App Mode” select “Dark”.
Mac users can switch to Settings, General, Appearance and switch between light, dark and auto.
If you’re one of the lucky ones, the next time you start your browser things should change and go to the Google search page.
Dark modes have become increasingly popular over the years on both PCs and smartphones, so this look can now be chosen. Most of the apps like WhatsApp and Facebook have also followed dark versions of their popular apps.