How is the color for the upvote count on comments calculated?

Question

I just answered a question in which the OP basically wants a mathematical model for doing interpolation between color points in a way which would look natural to the human eye (and which presumably is not what linear interpolation would produce).

My answer was to pre-pick N colors and simply project from the initial input range to these color bands.

Which led me to wonder... how is it done here on SO?

Answer 1

css

.supernova {
color: #FE7A15 !important;
}

.hot {
color: #CF7721 !important;
}

.warm {
color: #9B764F !important;
}

.cool {
color: #999 !important;
}

js

// e.g. options = { min: 15, max: 300, setIsValid: function }

var max = options.max;

var css = cur > max * 0.8 ? "supernova" : cur > max * 0.6 ? "hot" : cur > max * 0.4 ? "warm" : "cool";