Google initially launched a system-wide dark mode in 2019 with the release of Android 10. Since then, the company has been steadily adding dark mode support to its many services, and now, Google Search for desktop web is officially getting its share.
To access the new mode, simply open Google Chrome and go to Google Search. Click on ‘Settings’ on the bottom right corner and click on ‘Search Settings.’
Click on ‘Appearance’ in the top left menu and select one of these three options, ‘Device default,’ ‘Dark theme,’ or ‘Light theme.’
Further, once dark mode is enabled, it can be toggled on/off by going to ‘settings’ in the bottom right corner and clicking on the sun/moon icon. The same can also be done by accessing settings from the top-right gear icon.
Source: Google