JSFiddle - React, Tailwind, and code Playground

JavaScript

var css = ".Winning{color: #24CCFF;background-color: #FF8091;}.Losing{color: #2EFFCE;background-color: #DB4DFF;}.crayons{font-family: papyrus;font-size: 32pt;}";

var reg = /\.[a-zA-Z0-9]*\{[a-zA-Z0-9:\- #;]+\}/ig;
var matches = css.match(reg);
var classes = []
var classMap = {}

matches.map(function(item) {
    var cl = (item.split("{")[0])
    classes.push(cl)
    classMap[cl] = item.split("{")[1].split("}")[0]            
})

// All the classes in an array
console.log(classes);
console.log(classMap);