What is the right way to use colors when designing the interface of an app or website? Is strict compliance with safe colors necessary?

Question

User interface

I know that it is necessary to maintain proper contrast. Based on the W3C recommendations :
minimum WCAG requirements and increased WCAG requirements , it is necessary to observe a contrast ratio of at least 4.5:1 (increased 7:1 ) for body text, and 3:1 (increased 4.5:1 ) for large text . There is also a formula, and if necessary, you can use either online calculators to check, or download a program similar to Color Contrast Analyzer .
What about safe web colors? Here I am not very strong and I ask for your help. Do I understand correctly that all colors from the profile get into the networksRGB - is this the very notorious safe veta?
And even if, for example, my image has other colors (outside the given profile), then when displayed, say, in the browser, the colors are sort of compared, and a completely new image that matches this profile will be rendered?
At the same time, it also plays a role how wide the color gamut of the display is for the user, i.e. can it cover colors outside of sRGB . It turns out, if it can, then it makes sense to use more colors. Again, the question arises, how to check if the color is included in this scope?

Answer 1

https://en.wikipedia.org/wiki/Web_colors#Web-safe_...
https://habrahabr.ru/post/67831/
https://habrahabr.ru/post/220681/

Answer 2

Safe colors!.. :) There was a smell of punched cards.
B.Ts. were really needed in the 90s.
In the early 2000s, this was already more of a reinsurance, although a certain percentage of computers without true color were still in service.
For the last 10 years they have been of exclusively historical interest.