anchor.diff:  
     We apply the [Single Responsibility Principle](https:\/\/en.wikipedia.org/wiki/Single_responsibility_principle) to all Components, Services, and other symbols we create. This helps make our app cleaner, easier to read and maintain, and more testable.
   
  -  ### Rule of One
  -  <a id="01-01"></a>
  -  #### Style 01-01
  +  ### <a id="01-01"></a>Rule of One
  +  #### <a href="#01-01">Style 01-01</a>
   .s-rule.do
     :marked
       **Do** define one thing (e.g. service or component) per file.
  
positive.code: 
  .l-main-section
  :marked
    ### Folders-by-Feature Structure
    <a id="04-08"></a>
    #### Style 04-08
  
  .s-rule.do
    :marked
  
negative.code: 
  .l-main-section
  :marked
    ### <a id="02-06"></a>Directive Selectors
    #### <a href="#02-06">Style 02-06</a>
  
  .s-rule.do
    :marked
  