in src/com.jetbrains.youtrack.sdPlugin/libs/js/dynamic-styles.js [1:9]
const fadeColor = function (col, amt) {
const min = Math.min,
max = Math.max;
const num = parseInt(col.replace(/#/g, ''), 16);
const r = min(255, max((num >> 16) + amt, 0));
const g = min(255, max((num & 0x0000ff) + amt, 0));
const b = min(255, max(((num >> 8) & 0x00ff) + amt, 0));
return '#' + (g | (b << 8) | (r << 16)).toString(16).padStart(6, 0);
};