title: custom css for common w3.css classes
body: <p>I have been looking at the W3.CSS framework and at first sight looks interesting, BUT adding all the 'css' into the HTML seems to defeat the purpose of css. Take this for example (three rows with different widths but identical colours and justification):</p>
  
  
          <p>m4</p>
          <p>m6</p>
          <p>m2</p>
      
  
  <pre><code>&lt;div class="w3-row"&gt;
      &lt;div class="w3-col m4 w3-red w3-center w3-container"&gt;&lt;p&gt;m4&lt;/p&gt;&lt;/div&gt;
      &lt;div class="w3-col m6 w3-light-grey w3-center"&gt;&lt;p&gt;m6&lt;/p&gt;&lt;/div&gt;
      &lt;div class="w3-col m2 w3-light-grey w3-center"&gt;&lt;p&gt;m2&lt;/p&gt;&lt;/div&gt;
  &lt;/div&gt;
  
  &lt;div class="w3-row"&gt;
      &lt;div class="w3-col m4 w3-red w3-center w3-container"&gt;&lt;p&gt;m4&lt;/p&gt;&lt;/div&gt;
      &lt;div class="w3-col m6 w3-light-grey w3-center"&gt;&lt;p&gt;m6&lt;/p&gt;&lt;/div&gt;
      &lt;div class="w3-col m2 w3-light-grey w3-center"&gt;&lt;p&gt;m2&lt;/p&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>That's a lot of repetition and a nightmare to change afterward. Is there a way to move the w3 classes into a custom css or use a mechanism like a C header file to collect all common attributes?</p>