我试图使用CSS在React Js中仅在部分的右侧和左侧应用薄阴影，但我只在一侧得到阴影。下面是代码

.MainSection{
    margin-top:2%;
    background-color: white;
    width: 40%;
    border: solid 1.5px gray;
    box-shadow: -60px 0px 100px -90px #000000,60px 0px 100px -90px #000000;
    
}

import React from "react";
import "./MainSection.css";

function MainSection() {
  return (
    <div className="MainSection">
      <h1>MainSection</h1>
    </div>
  );
}

export default MainSection;