Where to put xsl:variable definition

Question

I apologize in advance if this is a really obvious question/answer for most of you.
I want to use this definition code to create a variable called color:
*<xsl:variable name="color" select="'red'"/>*
I want to include this code in my RTF template to display the contents of that variable:
*<?$color?>*
My question is this: where do I put the definition code? I've tried it in several different places, none of which have worked: at the top of my RTF template, on the top row of the table where I'm referring to it, and so forth.
When I run the preview, I get the typical error screen with this key line: Variable not defined: 'color'.

Answer 1

The subtemplate idea works quite well (mostly).
In my subtemplate, I defined this:
<?template:Format1?>
<?if:number(Sales) gt 1000000?><?attribute@incontext:color;'red'?> <?attribute@incontext:font-weight; 'bold'?><?end if?>
<?end Format1?>
In my template field, I call Format1 like this:
<?call@inlines:Format1?><?end call?>
Sure enough, my values are shown in bold red. Yay!!!
But now I've got extra vertical space in the affected cells. I've used table functions to align the values at the bottom of the cell. If I don't apply this conditional formatting, the row is what I'll call a "normal" height. When I apply the conditional formatting, the bold red numbers are displayed at the bottom of the cell as expected, but the row is twice as tall as its "normal" height.
The difference is found in the page source for the browser page. The <tr> tag shows a height of 13.216pt for the "normal" rows, but 25.933pt for the rows affected by the formatting. For some reason, BIP wants to generate a much taller row when it contains these formatted results.
I've experimented with attribute tags such as <?attribute@incontext:linefeed-treatment;'ignore'?> and <?attribute@incontext:height;14?>. I've used Word table formatting to fix the height of the row at exactly .3 inches. I removed the bold tag, and just kept the font color. None of those ideas was successful in removing the extra height.
Thoughts?