.code-box {
  position: relative;
  background: #f5f5f5;
  border: 1px solid #ddd;
  padding: 1em;
  border-radius: 8px;
  overflow: auto;
  font-family: 'Courier New', monospace;
  margin-bottom: 1em;
}
.code-box::before {
  content: attr(data-lang);
  position: absolute;
  top: 0;
  left: 0;
  background: #e53935;
  color: white;
  font-size: 12px;
  padding: 2px 8px;
  border-bottom-right-radius: 6px;
  font-family: sans-serif;
}
.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: #4caf50;
  color: white;
  border: none;
  padding: 5px 10px;
  font-size: 12px;
  cursor: pointer;
  border-radius: 4px;
}
.copy-btn:active {
  background: #388e3c;
}

Copy

function copyCode(btn) {

  const code = btn.previousElementSibling.innerText;

  navigator.clipboard.writeText(code).then(() => {

    btn.innerText = "Copied!";

    setTimeout(() => btn.innerText = "Copy", 2000);

  });

}

Copy

Your code goes here...