XF 2.0 Template modification for non-master template - best practice?

[S Thomas]

Situation: I have a template which does not exist in the master template. This template gets edited frequently by the customer. I have to generically add something to the template everytime the customer adds a structure to the template.
Example:

.class-x {
    color:red;
}

Template modification:

.class-x, .class-x-inner { #TMS adds ", .class-x-inner"
    color:red;
}

Yea, pretty much that. That works with a regex and template modifications. However, as I mentioned, the template does not exist in the master style, thus would get deleted when master data would be rebuilt even if I added that template to the master style (right?).
What would be the best approach here? Tell the customer to add the "inner" class himself? Create a master template and stick that to an addon?

 

[Kirby]

A template does not necessarily have to exist in MASTER for template modifications to work; as long as the regex works they will be active in child styles.
So you can just create the template modifiction as if the template existed.

 

[S Thomas]

Huh? Either I'm blind or I'm pretty sure that did not work when I tried it out. Gonna report back in a sec.

 

[S Thomas]

Alrighty, nvm, I'm blind.