const f: (s: string, a: number) => string = (s, a) => {
            const m = /rgba?\((\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*(,\s*\d+[\.\d+]*)*\)/g.exec(s);
            if (m && m.length > 3) {
                a = a > 1 ? (a / 100) : a;
                return 'rgba(' + [m[1], m[2], m[3], a].join(',') + ')';