This website is made with TYPO3 and the Camino Theme.
Special features on this site are:

• In the header bar the dark/light toggle on the right side.
• For preview of the different color modes you can hover over “The Theme” in the header bar and then select one of the four different color names.

For both options:  After switching you can select all pages, your choice is saved on your own device. There is no tracking involved, so I don't know about your choice.