Dark Mode Is a Second Design, Not a Filter
Flip a palette and the page technically works. It also feels like a photo negative.
Contrast budgets flip
On paper-light backgrounds, texture can be loud. In the dark, the same lines glow. Everything decorative needs to drop two notches of opacity.
Accents work harder
A mid-tone accent that pops on cream can go muddy on near-black. Shift it lighter and greener rather than just brighter.
That is why this site's teal is a different teal after dark.