Color font in character strings of plain text

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

Description:
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.