How to accurately determine the numerical value of a font's weight for CSS?

Question

css

As you know, in CSS, weight can be set in numbers: 100, 200 ... 700, etc. And how exactly do you know which fat content corresponds to which figure? In graphic editors, they are denoted by words like: thin, medium, semibold.

Answer 1

Compliance is set when connecting the font

@font-face {
 font-family: "Open Sans";
 src: url("/fonts/OpenSans-Regular-webfont.woff2") format("woff2"),
        url("/fonts/OpenSans-Regular-webfont.woff") format("woff");
 font-weight: 300;
}

@font-face {
 font-family: "Open Sans";
 src: url("/fonts/OpenSans-Bold-webfont.woff2") format("woff2"),
        url("/fonts/OpenSans-Bold-webfont.woff") format("woff");
 font-weight: 500;
}

Answer 2

And the approximate correspondence of numbers in CSS and font names is here: https://developer.mozilla.org/en/docs/Web/CSS/font...