title: Apply same style to all tr and td of multiple table having same parent CSS class
body: <p>I am trying to merge the following two css classes:</p>
  
  <pre><code>.addActivityTable table tr {
      border: none;
  }
  
  .addActivityTable table td {
      border: none;
  }
  </code></pre>
  
  <p>as</p>
  
  <pre><code>.addActivityTable table tr, table td {
      border: none;
  }
  </code></pre>
  
  <p>It is not taking any effect, also I have tried:</p>
  
  <pre><code>.addActivityTable table tr, td {
      border: none;
  }
  </code></pre>
  
  <p>This also doesn't work. Is there any way to merge these? </p>
  
  <p>If someone point me a good article or blog on these kind of css selectors, it would be helpful to me to learn.</p>