Hover on text popup textbox

Hi,

I´m trying to get a popup textbox when hovering over a text.

I´m using this website as a reference: http://www.scientificpsychic.com/etc/css-mouseover.html

I have implemented the CSS code for class dropt in a CSS file and uploaded it to the server and successfully choosen it as the Custom CSS for the Report.

I have put the dropt in the CSS Class the below code in the CSS Style but it does not work.

<span class="dropt" title="Title for the pop-up">Hot Zone Text

  <span style="width:500px;">Pop-up text</span>

</span>

Anyone knows what I´m doing wrong or has any other idea of how to implement hover on text popup textbox?

Thanks,

Anders