如何为弹出窗口的按钮赋予样式

<button class="popup-button">弹出窗口按钮</button>

<style>
.popup-button {
  background-color: #007bff;
  color: #fff;
  border: none;
  padding: 10px 20px;
  font-size: 16px;
  border-radius: 5px;
}
</style>

<button id="popup-button">弹出窗口按钮</button>

<script>
var button = document.getElementById("popup-button");
button.style.backgroundColor = "#007bff";
button.style.color = "#fff";
button.style.border = "none";
button.style.padding = "10px 20px";
button.style.fontSize = "16px";
button.style.borderRadius = "5px";
</script>

<button class="btn btn-primary">弹出窗口按钮</button>

<!-- 引入Bootstrap样式表 -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css">