1.代码如下

<!DOCTYPE html>

<html lang="en">

  <head>

    <meta charset="UTF-8" />

    <meta name="viewport" content="width=device-width, initial-scale=1.0" />

    <link rel="stylesheet" href="./style.css" />

    <title>Document</title>

    <style>

      * {

        box-sizing: border-box;

      }

      body {

        display: flex;

        justify-content: center;

        align-items: center;

        height: 100vh;

        margin: 0;

      }

      .container {

        display: flex;

        width: 90vw;

      }

      .panle {

        background-size: auto, 100%;

        background-position: center;

        background-repeat: no-repeat;

        border-radius: 50px;

        color: #fff;

        flex: 0.5;

        cursor: pointer;

        height: 80vh;

        position: relative;

        margin: 10px;

        transition: flex 0.7s cubic-bezier(0.05, 0.6, 0.4, 0.9);

      }

      .panle h3 {

        font-size: 24px;

        opacity: 0;

        position: absolute;

        bottom: 20px;

        left: 20px;

        margin: 0;

        transition: opacity 0s ease-in 0s;

      }

      .panle.active {

        flex: 5;

      }

      .panle.active h3 {

        opacity: 1;

        transition: opacity 0.3s ease-in 0.4s;

      }

      @media (max-width: 500px) {

        .container {

          width: 100vw;

        }

        .panle:nth-of-type(4) {

          display: none;

        }

        .panle:nth-of-type(5) {

          display: none;

        }

      }

    </style>

  </head>

  <body>

    <div class="container">

      <div class="panle" style="background-image: url(./img/img1.jpg);">

        <h3>海阔天空</h3>

      </div>

      <div class="panle" style="background-image: url(./img/img2.jpg);">

        <h3>蓝天白云</h3>

      </div>

      <div class="panle" style="background-image: url(./img/img3.jpg);">

        <h3>山川湖海</h3>

      </div>

      <div class="panle" style="background-image: url(./img/img4.jpg);">

        <h3>星空灿烂</h3>

      </div>

      <div class="panle" style="background-image: url(./img/img5.jpg);">

        <h3>绿树成荫</h3>

      </div>

    </div>

    <script>

      const penles = document.querySelectorAll(".panle");

      penles.forEach((panle) => {

        panle.addEventListener("click", () => {

          removeClass();

          panle.classList.add("active");

        });

        function removeClass() {

          penles.forEach((penle) => {

            penle.classList.remove("active");

          });

        }

      });

    </script>

  </body>

</html>