[Avamander]

> Users are fully capable of adjusting the brightness and contrast of their monitors.

It'd be a hack. The buttons are not sturdy enough for it, they're even not designed for it and the colour representation will be very incorrect.

Instead of asking every website to blast every user with the highest amount of contrast, modify your own display to do so if your eyes need it. That way the need and the solution is localized to where it should be.