anchor.diff:    1. We can co-locate the CSS code of each component with the TypeScript and HTML code of the component,
        which leads to a neat and tidy project structure.
        
  -  1. 我们可以让每个组件的CSS代码和它的TypeScript代码、HTML代码放在一起，这将产生清爽整洁的项目结构。
  +  1. 我们可以让每个组件的CSS代码和它的TypeScript代码、HTML代码放在一起，这将促成清爽整洁的项目结构。
        
     1. We can change or remove component CSS code in the future without trawling through the
        whole application to see where else it may have been used. We just look at the component we're in.
  
positive.code:   ### 元数据中的样式表URL
    
    We can load styles from external CSS files by adding a `styleUrls` attribute
    into a component's `@Component` or `@View` #{_decorator}:
    
    我们还可以通过给组件的`@Component`或`@View`#{_decoratorCn}中添加一个`styleUrls`属性来从外部CSS文件中加载样式：
    
  +makeExample('component-styles/ts/app/hero-details.component.ts', 'styleurls')
  
  
negative.code:   * An element that would be a Shadow DOM host in native encapsulation has a
      generated `_nghost` attribute. This is typically the case for component host elements.
      
    * 一个元素在原生包装方式下可能是Shadow DOM的宿主，在这里被自动添加上一个`_nghost`属性。
      这是组件宿主元素的典型情况。
      
    * An element within a component's view has a `_ngcontent` attribute 
    that identifies to which host's emulated Shadow DOM this element belongs.
    
    * 组件视图中的每一个元素，都有一个`_ngcontent`属性，它会标记出该元素是哪个宿主的模拟Shadow DOM。
    
    The exact values of these attributes are not important. They are automatically
    generated and we never refer to them in application code. But they are targeted
    by the generated component styles, which we'll find in the `<head>` section of the DOM:
    
    这些属性的具体值并不重要。它们是自动生成的，并且我们永远不会在程序代码中直接引用到它们。
    但它们会作为生成的组件样式的目标，就像我们在DOM的`<head>`区所看到的：
    
  code-example(format="").
  