> Similarly for header-navigation and theme-toggle
The theme toggle has three states. How do you model this with a checkbox?
Why does a site even need a light/dark toggle, when you can just use prefers-color-scheme in CSS, and the user can select that in their browser settings?
(Also, technically, alternative stylesheets can be defined in HTML, except every browser except Firefox removed it: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/...)
It could be done with :indeterminate state (so key in a cookie would be absent or removed when switching), but I'd probably would do it with radios instead
It's possible to have a 3-states CSS switch/slider that controls site theme. Google it or ask AI assistant.