Encore\Admin\Widgets\Chart\Chart::color PHP Method

    public static function color($color = '')
    {
        $colors = ['#dd4b39', '#00a65a', '#f39c12', '#00c0ef', '#3c8dbc', '#d2d6de'];
        return $color ? $color : $colors[array_rand($colors)];
        //sprintf('#%06X', mt_rand(0, 0xFFFFFF));
    }