title: Declaring same CSS class multiple time
body: <pre><code>&lt;div class="big_box"&gt;haha&lt;/div&gt;
  &lt;div class="small_box"&gt;haha&lt;/div&gt;
  </code></pre>
  
  <p>This (type 1) seems workable :-</p>
  
  <pre><code>.big_box, .small_box { border:1px solid #ccc; /* lengthy attributes*/}
  .big_box { width:150px; height:150px; }
  .small_box { height:140px; width:140px; }
  </code></pre>
  
  <p>This (type 2) also works :-</p>
  
  <pre><code>.big_box { border:1px solid #ccc; width:150px; height:150px; /* same lengthy attributes*/}
  .small_box { border:1px solid #ccc; width:150px; height:150px; /* same lengthy attributes* }
  </code></pre>
  
  <p>Of course, type 2 is lengthy and repeating for most of the common attributes (with same value),<br>
  is there any issue for using type 1 ?<br>
  (or simply this is allowed ?)</p>
  
  <p><strong>P.S</strong> type 3 works too (but I find is hard to manage) ... <strong>if</strong> </p>
  
  <pre><code> &lt;div class="box big"&gt;haha&lt;/div&gt;
  </code></pre>
  
  <p>And</p>
  
  <pre><code>.box { border:1px solid #ccc; /* lengthy attributes*/}
  .big { width:150px; height:150px;}
  </code></pre>