title: ExtJs 4 How to change the header's height of Accordion
body: <p>I want to change the header's height of Accordion, I use a css to set the header's height.</p>
  
  <pre><code>#panel1 .x-accordion-hd{ height: 40px;}
  </code></pre>
  
  <p>The height is changed but the content of the panel is covered by the header and when the panel is collapsed the next header will cover part of the previous header. Here is the picture. 
    Any help will be appreciated.</p>
  
  <p><img src="https://i.stack.imgur.com/pWLTY.jpg" alt="The effect"></p>