title: Difference between . and # in CSS
body: <p>I have been learning CSS over the past couple of days and always wondered what the different with the <code>.</code> or <code>#</code> when declaring a header was. Example:</p>
  
  <pre><code>.test
  {
    some stuff here
  }
  
  #test
  {
    Some stuff here
  }
  </code></pre>
  
  <p>What are the key differences between the <code>.</code> and the <code>#</code>?</p>