How to configure so that the current Style affects current text input only

[jokinjo]

I have a text file that I want to annotate with a text style that stands out from the original content.
I tried global Style: Global Override AND Global Style : Default Style (in the Style Configurator). Each of these reformats the original content as well as the current input text (for the annotations.)
As far as I can see, nobody has wanted to do this? Thanks! I am hoping that this is an easy one and not a duplicate question.

[Eko palypse]

@jokinjo

that is basically what lexers do, which means you need to define your own
user defined language or if it is all about having some text highlighted in a different
color then you might think about using (mouse-right-click in document) Style token
feature.

[jokinjo]

@Eko-palypse
I finally got it using a user-defined language.

Thank You So Much!