Cfinput tooltip css styling

Question

Hi!
I have the code below and I want to know how to create a css rule to add style to the tooltip within cfinput. It is displayed by default, however, i want to format how it looks. Any ideas?
<div class="container">
<h1> Create user </h1>
<cfform  id="form" action="processusercreation.cfm" method="post" >
<table>
<tr>
<td id="formleft">
  Username
</td>
<td id="formright">
     <cfinput type="text"
        tooltip="Desired username, with 20 letters and numbers, no spaces"
        required="yes"
        validate="regular_expression"
        pattern="^[a-zA-Z0-9]+$"
        message="~Hey, there is something wrong with your username~"
        validateat="onsubmit,onserver"
        name="Username"
  maxlength="17">
     </td>
</tr>

Answer 1

The following solution might appear cumbersome, as it involves 2 CFM pages, but it is the only one I can think of:
In your form page:
<cfinput type="text"
        sourcefortooltip="tooltipstyle.cfm"
        required="yes"
        validate="regular_expression"
        pattern="^[a-zA-Z0-9]+$"
        message="~Hey, there is something wrong with your username~"
        validateat="onsubmit,onserver"
        name="Username"
      maxlength="17">
In the page tooltipstyle.cfm:
<!--- implement the style you want --->
<span style="color:red;font-size:200%;">Desired username, with 20 letters and numbers, no spaces</span>