现在，我已经像这样在angular.json文件中定义了默认的CSS文件
"styles": [
"src/assets/demo5/base/style-A.css",
"src/assets/vendors/base/vendors-A.css",
"src/styles.css"
],
我希望当用户单击某个功能时，应替换默认的CSS文件
"styles": [
"src/assets/demo5/base/style-B.css",
"src/assets/vendors/base/vendors-B.css",
"src/styles.css"
],