How to get a table cell in HTML to both right align and have text color set

I need some HTML guidance - probably very simple to fix what I am doing wrong.  I am trying to format an email in Microsoft Flow and have the following scenario:

In Flow, I calculate the difference between two numeric fields to send out in the email.  If the difference is negative, i want to format the fields by enclosing it in parenthesis but also want it to be in red, otherwise green.  The email formats a table of both fields and calculated values.  The table has two columns, the left for a description and the right for values.

i know that the detection of negative values works fine as the display was easy to format with () and it is showing up that way.  However, I cannot get the color to appear.

Flow details - if the value is negative, I do a substring() to add () but then set a string variable - let's call it colorname - to red else green if the value is positive.  The HTML code then looks like this (modified for this question):

<tr>
<td>Description of value</td>
<td align=right> valuestring</td>
</tr>

Ant that works perfectly without the color.  If I modify the td to add color it fails

<td align=right; color=colorname> valuestring</td>    I get neither color nor right alignment. I also tried these variants

<td {align:right; color:colorvale;} valuestring</td>
<td align;right; color:colorvalue;} valuestring</td>
<td {text-align:right; color:colorvalue;} valuestring</td>

and probably some others I am forgetting.  Mostly the results have been all no color and left alignment.

Before you comment about colorname being a problem, let me tell you that when Flow runs I can view all the details, and it shows color=red or color=green indicating that the variable contents have been used, so I am somewhat confident that it is sending out the right HTML but not right in the sense of it giving me the results I want.

As I said to start, it's probably something simple, but if you can help me figure it out I would be most appreciative.