Conditional Formatting

I need to know how to code in XSL for SharePoint 2010 (via SharePoint Designer) the following statement for a webpart:

If the created date of an item is older than two days, show alert icon on alert column.

The conditional formatting would be something like this:

<td align="center">
            <xsl:attribute name="style">
                        <xsl:if test="ddwrt:DateTimeTick(ddwrt:GenDisplayName(string($thisNode/@Created))) &lt; ddwrt:DateTimeTick(ddwrt:GenDisplayName(string($Today)))" ddwrt:cf_explicit="1">color: #FF0000;</xsl:if>
            </xsl:attribute>
            <span class="fa fa-exclamation" />
</td>


I have not been able to get this to work. It is a custom webpart with filters already applied to it.