如何在 reactjs 中有一个粘性导航栏

Question

新手上路，请多包涵

我的导航栏隐藏了导航栏下方的内容。此外，它粘在左侧而不是中间部分。我希望有人能告诉我正确的方法来制作导航栏正确的方法来制作一个即使在我们滚动时也能保持在原位的粘性导航栏。

代码沙箱 https://codesandbox.io/s/clever-voice-24udr

导航栏.js

 import React, { Fragment } from "react";
import { Link } from "react-router-dom";
import { Button } from "react-bootstrap";

const NavbarPage = () => {
  const guestLinks = (
    <ul>
      <li>
        <Link to="/">
          <Button className="btn btn-primary createNew">Create New</Button>
        </Link>
      </li>
      <li>
        <Link to="/about">
          <Button className="btn btn-danger signOut">Sign out</Button>
        </Link>
      </li>
    </ul>
  );
  return (
    <nav className="navbar bg-white">
      <h3 className="titleName">
        <Link to="/">
          <i className="fas fa-pen" /> demo
        </Link>
      </h3>
      {guestLinks}
    </nav>
  );
};

export default NavbarPage;

 .navbar {
  position: fixed;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.7rem 2rem;
  overflow: hidden;
  z-index: 1;
  width: 88.15%;
  margin: auto;
  top: 0;
  border-bottom: solid 1px var(--primary-color);
  opacity: 0.9;
  top: 0;
  box-shadow: 12px 0 15px -4px rgba(31, 73, 125, 0.8),
    -12px 0 8px -4px rgba(31, 73, 125, 0.8);
  box-shadow: 0 9px 0px 0px white, 0 -9px 0px 0px white,
    12px 0 15px -4px rgba(31, 73, 125, 0.8),
    -12px 0 15px -4px rgba(31, 73, 125, 0.8);
}