title: Changing color of table row by a class in tr
body: <p>I want to change the background color of all td in a tr just using a class in the tr. I am using the following css</p>
  
  <pre><code>tr .yellow td{
  background-color: yellow;
  </code></pre>
  
  <p>}</p>
  
  <p>And I have following html</p>
  
  <pre><code>&lt;tr class="yellow"&gt;&lt;td&gt;&lt;/td&gt; &lt;td&gt;&lt;/td&gt;&lt;/tr&gt;
  </code></pre>
  
  <p>But the background color is not changing. What is the mistake here?</p>