title: How to check if browser is Firefox in CSS
body: <p>I was reading how to do this,...  but have not come up with a good answer for this</p>
  
  <p>the thing is that, in eclipse's internal browser this css looks weird because of the margin</p>
  
  <pre><code>#tabs {
      margin-top:-50px;
      float:left;
      font-size:100%;
      line-height:10px;
      vertical-align:top;
      }
  </code></pre>
  
  <p>but in firefox it works fine.. so i am tring to say something like if firefox use margin otherwise do that read the margin-top.. i saw something like this but is not working (and again new to this :) ) thank you for your help</p>
  
  <pre><code>#tabs {
      [if Gecko] margin-top:-50px;   (not working)
      float:left;
      font-size:100%;
      line-height:10px;
      vertical-align:top;
      }
  </code></pre>