<section>
  <h3>CSS padding-top</h3>
  <div class="container" data-aspect="padding-top">
    <div class="box">
      <img src="https://picsum.photos/900/508?random=2" alt="">
    </div>
  </div>
  <p style="text-align: right">Press and hold me to drag left or right</p>
</section>
<section>
  <h3>CSS Variables</h3>
  <div class="container" data-aspect="CSS Variables" id="box">
    <img src="https://picsum.photos/900/508?random=4" alt="">
  </div>
  <p style="text-align: right">Press and hold me to drag left or right</p>

</section>
<section>
  <h3>CSS aspect-ratio</h3>
  <div class="container" data-aspect="aspect-ratio">
    <img src="https://picsum.photos/900/508?random=6" alt="">
  </div>
  <p style="text-align: right">Press and hold me to drag left or right</p>

</section>
@import url("https://fonts.googleapis.com/css2?family=Exo:wght@600&display=swap");

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

img {
  display: block;
  vertical-align: top;
}

body {
  width: 100vw;
  min-height: 100vh;

  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
  font-family: "Exo", Arial, sans-serif;
  background-color: #f7f7f7;

  padding: 20px;
}

section {
  max-width: 40vw;
  margin: 0 auto;
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  gap: 10px;
  box-shadow: 0 0 0 6px rgb(0 0 0 / 13%);
  border-radius: 6px;
  padding: 10px 0;
}

p {
  width: 100%;
  padding-right: 5px;
  font-size: 14px;
  color: #666;
}

.container {
  border: 1px dashed #f36;
  border-radius: 1px;
  width: 100%;
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  resize: horizontal;
}

.container[data-aspect="padding-top"] .box {
  height: 0;
  padding-top: 56.25%;
  width: 100%;
  position: relative;
}

.container[data-aspect="padding-top"] img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}

.container[data-aspect="CSS Variables"] img {
  --ratio: 16/9;
  height: calc(var(--width) * 1 / (var(--ratio)));
  width: 100%;
}

.container[data-aspect="aspect-ratio"] img {
  width: 100%;
  aspect-ratio: 16 / 9;
}
var ro = new ResizeObserver((entries) => {
  for (let entry of entries) {
    const cr = entry.contentRect;
    entry.target.style.setProperty("--width", `${cr.width + 2}px`);
  }
});

const box = document.getElementById("box");
ro.observe(box);
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