How can I do to change the color of the dates?

Question

I am working on a project using React.js and I want to change the color of the dates for instance, now the color is black but I want purple. How can I do to to that ?

my datepicker

Here is my code :

https://codesandbox.io/s/react-datepicker-forked-h6wre?file=/src/index.js

import React, { useState } from "react";
import ReactDOM from "react-dom";
import { DatePicker, RangeDatePicker, TimePicker } from "@y0c/react-datepicker";

const Panel = ({ header, children }) => (
  <div style={{ height: "300px" }}>
    <h1>{header}</h1>
    <div>{children}</div>
  </div>
);

function App() {
  const [startDate, setStartDate] = useState(new Date());
  return (
    <DatePicker selected={startDate} onChange={(date) => setStartDate(date)} />
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

Thank you very much !