title: Class names concatenated or separated by a space
body: <p>When do you separate style classes with a space? So for example: what is the difference between the following two blocks of css?</p>
  
  <p><strong>Block 1</strong>:</p>
  
  <pre class="lang-css prettyprint-override"><code>div {
      color: brown;
  }
  
  div.special {
      font-size: 18px;
  }
  </code></pre>
  
  <p><strong>Block 2</strong>:</p>
  
  <pre class="lang-css prettyprint-override"><code>div {
      color: brown;
  }
  
  div .special {
      font-size: 18px;
  }
  </code></pre>
  
  <p>This is the HTML:</p>
  
  <pre><code>&lt;div class="special"&gt;The quick brown fox jumps over the lazy dog.&lt;/div&gt;
  </code></pre>
  
  <p>I tried both versions. Only with block 1 the text wil be in font size 18.</p>