<details open>
  <summary>Container</summary>
  <div>
    The Content Goes Here
  </div>
</details>
<details>
  <summary>Container</summary>
  <p>
    The Content Goes Here
  </p>
</details>
<details>
  <summary>Container</summary>
  <p>
    The Content Goes Here
  </p>
</details>
body {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-flow: column;
}

details {
  width: 100%;
  margin-bottom: 8px;
}

test {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
}

summary {
  background-color: gray;
  padding: 16px;
  color: white;
  font-weight: bold;
}

details[open] {
  background-color: whitesmoke;
}

details[open] p {
  padding: 16px;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.