title: what is the meaning of 'a' and 'h1' in '#main-navigation h1 a'
body: <p>As the title suggests, I want to know the meaning of a and h1 in '#main-navigation h1 a'. Here is the code:</p>
  <pre><code>#main-navigation {
    ...
  }
  
  #main-navigation a {     
    ...
  }
  
  #main-navigation a:hover,
  #main-navigation a:active {
    color: #cf79f1;
  }
  
  #main-navigation h1 a:hover,
  #main-navigation h1 a:active {
    color: white;
  }
  </code></pre>