Question Reg HTML Output

Hi Experts.

My actual question was answered in the below post and very well explained.
http://powershell.com/cs/forums/t/12627.aspx

But the requirement what i have is bit different.

$Style = "<style>"
$Style = $Style + "BODY{background-color:#D7D8D8;}"
$Style = $Style + "TABLE{border-width: 1px;border-style: solid;border-color: black;border-collapse: collapse;}"
$Style = $Style + "TH{border-width: 1px;padding: 0px;border-style: solid;border-color: black;}"
$Style = $Style + "TD{border-width: 1px;padding: 0px;border-style: solid;border-color: black;}"
$Style = $Style + "</style>"
$ServerList = "localhost"
$serviceList =  &{$args} "Vds","bits"

$body = gwmi win32_process -cn $_ | ? {$_.name -eq "certainproces.exe"} select __Server,Name,@{n='Memory(Gb)';e={"{0:n0}" -f ($_.ws/1gb)}} | ConvertTo-Html -Fragment}

I want to color red if the output of this is more than 20Gb  anything less than that should be in green color.