The question has a quick answer: you can't. And that's because each uniqueness will require a different approach: there will be users who can't stand the light because it burns their eyes, and there will also be users with low vision who really need the light. So the best solution is to provide them with options from which they can choose the one that suits them best. Twitter solved this problem very well with the themes "default" (light), "dim" (dark), and "lights off" (high contrast).
But in practice, what is the issue of high contrast?
It consists of a more limited palette that focuses on having a czech republic mobile numbers list higher contrast between colors, and that usually means fewer colors. To ensure the minimum contrast ratio of 7:1 required by WCAG AAA level, the high contrast theme will benefit from a darker background, usually pure black, as opposed to dark mode, which balances between shades of gray. The colors, rather than the original palette, will be extremely contrasting shades with the background, usually neon yellow, although this is not a rule. Sometimes you may need to use outlines to delimit components when you don't have colors to do so.
How exactly does high contrast help accessibility?
There are two types of extreme color blindness:
Monochromatic, in which the person can only see one color and its shades, plus shades of gray.
And Achromatic, the person cannot perceive any color and sees everything in shades of gray.
Both cases involve relying on contrast between shades of grey, which is difficult to avoid when you are not colour-blind. High contrast will ensure that colours do not blend together, providing clear information and improving the user experience.
Color blindness itself is not a defined rule, each person will have a different type and level from another. So, besides the two extreme cases I have mentioned, there are some people who can see two or more colors, but depending on their condition, contrast can be really important and game-changing.
To meet WCAG C success criteria 1.4.6: Contrast (Enhanced) (Level AAA) and 1.4.11: Non-Text Contrast (Level AA) , every text, essential images, and interface components are required to have a minimum contrast ratio, which is often difficult to achieve when there is a brand-defined palette. When a high contrast theme is provided, light and/or dark themes become optional so that the standard palette can remain intact once another theme is available that provides the required accessibility.