title: How to make links clickable with negative z-index?
body: <p>I am  using <code>drop-down</code> menu in my header for notification, but when drop down opens all the div's behind that are visible then I gave <code>z-index</code> to all the divs but the links on those div's are not clickable now!</p>
  
  <p>drop-down div CSS:</p>
  
  <pre><code>.drop-down{
     overflow:scroll;
     overflow-x:hidden;
  }
  </code></pre>
  
  <p>and the div's behind it are</p>
  
  <pre><code>#main-div{
     z-index:-1;
     position:absolute;
  }
  </code></pre>