Inserting a blank table row with a smaller height

I have a table consisting of a header row and a couple of data rows. What I want to do is to create a blank row in between the header and the data rows, but I want this blank row to be smaller in height than the other rows (so that there isn't such a large gap).

How can I accomplish this?

My HTML mark-up code for the table is as follows:

<table class="action_table">
    <tbody>
        <tr class="header_row">
            <td>Header Item</td>
            <td>Header Item 2</td>
            <td>Header Item 3</td>
        </tr>            
        <tr class="blank_row">
            <td bgcolor="#FFFFFF" colspan="3">&nbsp;</td>
        </tr>
        <tr class="data_row">
            <td>Data Item</td>
            <td>Data Item 2</td>
            <td>Data Item 3</td>
        </tr>
    </tbody>
</table>

Just add the CSS rule (and the slightly improved mark-up) posted below and you should get the result that you're after.

CSS

.blank_row
{
    height: 10px !important; /* overwrites any other rules */
    background-color: #FFFFFF;
}

HTML

<tr class="blank_row">
    <td colspan="3"></td>
</tr>

Since I have no idea what your current stylesheet looks like I added the !important property just in case. If possible, though, you should remove it as one rarely wants to rely on !important declarations in a stylesheet considering the big possibility that they will mess it up later on.