Visitors can choose between light/dark view

I’m working on a new website in Elements and I want to give visitors the option to choose between a light and a dark view themselves.
Is there an easy way to do this so they can switch modes?

light-dark-view

Right now, the theme will only switch automatically based on the user’s system (or browser) settings; it cannot be changed manually.

I do think this automatic setting is the way to go, as it’s always best to respect the mode the user has chosen on their system.