(Angular 7，Chrome扩展)为什么mat对话框在网页中可以正确呈现，而在chrome扩展中却不能？(使用复制回购)

{
  "manifest_version": 2,
  "name": "My Extension",
  "version": "1.0",
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": ["content.js"],
      "css": ["styles.css"]
    }
  ],
  "web_accessible_resources": [
    "https://unpkg.com/@angular/material/prebuilt-themes/indigo-pink.css"
  ]
}

{
  "manifest_version": 2,
  "name": "My Extension",
  "version": "1.0",
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": [
        "https://unpkg.com/@angular/material@7.0.0/bundles/material.umd.js",
        "content.js"
      ],
      "css": ["styles.css"]
    }
  ]
}

{
  "manifest_version": 2,
  "name": "My Extension",
  "version": "1.0",
  "permissions": [
    "activeTab",
    "https://unpkg.com/*"
  ],
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": [
        "https://unpkg.com/@angular/material@7.0.0/bundles/material.umd.js",
        "content.js"
      ],
      "css": ["styles.css"]
    }
  ]
}

{
  "manifest_version": 2,
  "name": "My Extension",
  "version": "1.0",
  "permissions": [
    "activeTab",
    "https://unpkg.com/*"
  ],
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": [
        "https://unpkg.com/@angular/material@7.0.0/bundles/material.umd.js",
        "content.js"
      ],
      "css": ["styles.css"]
    }
  ]
}

// 初始化Angular应用
angular.element(document).ready(function() {
  angular.bootstrap(document, ['myApp']);
});

@import "https://unpkg.com/@angular/material/prebuilt-themes/indigo-pink.css";