画像で横幅が-90度回転した場合に縦に合わせる #CSS

<!DOCTYPE html>
<html lang="ja">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Rotate and Center with Proportional Div2</title>
  </head>
  <body>
    <div class="p-body">
      <img class="div1" src="./img/blue-tit-8024809_1280.png" alt="" width="1280" height="640" />
      <img class="div2" src="./img/img2.webp" alt="">
    </div>

    <style>
      body {
        margin: 0;
      }
      .p-body {
        position: relative;
        height: 100vh;
        display: flex;
        justify-content: center;
      }
      .div1 {
        height: auto;
        width: calc(100vh - 72px);
        object-fit: contain;
        transform: translateY(36px) rotate(-90deg);
      }
      .div2 {
        position: absolute;
        top: calc(50% + 36px);
        left: 50%;
        width: 33vw;
        transform: translate(-50%, -50%);
        background-color: rgb(10, 42, 42);
      }
    </style>
    <script>
      document.addEventListener("DOMContentLoaded", function() {
        const div1 = document.querySelector('.div1');
        const div2 = document.querySelector('.div2');

        function updateDiv2Width() {
          const div1Width = div1.naturalWidth;
          const div1Height = div1.naturalHeight;
          const aspectRatio = div1Height / div1Width;

          const div1RotatedHeight = window.innerHeight - 72
          const div1RotatedWidth = div1RotatedHeight * aspectRatio;

          div2.style.width = `${div1RotatedWidth}px`;
        }

        div1.onload = updateDiv2Width;

        // If the image is already loaded (from cache), trigger the onload event manually
        if (div1.complete) {
          updateDiv2Width();
        }

        window.addEventListener('resize', updateDiv2Width);
      });
    </script>

  </body>
</html>