Color font in character strings of plain text

Hi. I’m using Atom version 1.39.1 x64 in Windows operating system,
How would you color code specific character string in plain text?
Can this be done in File | Stylesheet … ?

I’m trying to assign a color to the font in specific character strings in plain text.
For example, in a plain text document, I would like to color “error” to orange.
“error: the machine shut down”
Thank you.