css_scope

:scope属于 css 伪类，它表示作为选择器要匹配的参考点元素

/* 当前的:scope 等效于 :root */
:scope {
  background-color: lime;
}

当从 DOM API 使用，如：querySelector(), querySelectorAll(), metchees()或Element.closet(),:scope匹配你调用的 API 元素

let paragraph = document.getElementById("para");
let output = document.getElementById("output");

if (paragraph.matches(":scope")) {
  output.innerText = "Yep. the element is its own scope as expected!";
}