为youtube视频添加神奇的弹出窗口

<button onclick="openPopup()">点击打开弹出窗口</button>

<div id="popup" class="popup">
  <div class="popup-content">
    <span class="close" onclick="closePopup()">&times;</span>
    <h2>神奇的弹出窗口</h2>
    <p>这是一个神奇的弹出窗口，可以用于展示视频相关的信息。</p>
  </div>
</div>

.popup {
  display: none;
  position: fixed;
  z-index: 1;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0, 0, 0, 0.5);
}

.popup-content {
  background-color: #fefefe;
  margin: 15% auto;
  padding: 20px;
  border: 1px solid #888;
  width: 80%;
}

.close {
  color: #aaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
  cursor: pointer;
}

.close:hover,
.close:focus {
  color: black;
  text-decoration: none;
  cursor: pointer;
}

function openPopup() {
  document.getElementById("popup").style.display = "block";
}

function closePopup() {
  document.getElementById("popup").style.display = "none";
}