How to change color of fieldname when checkbox == true

I am brand new to the coding and debugging side of Salesforce. As I am learning, there is something that I have been trying to figure out the past few days. My goal is to have a checkbox on a Contact's page, with field name "Inactive". When the checkbox== false, it shows Inactive in the default black font color. When the checkbox == true, I want the field name "Inactive" to change to a red font color.

I've found ways to change the field name font color using CSS, but I don't know where to start in programming this. I keep going back to Apex triggers, and looking up examples online but I can't find anything similar to what I'm trying to do. Can I work right in the Contacts -> Triggers console or is there another environment I should be working in?

Again, I'm not yet savvy with Apex/Java, but if anyone has any insight on at least how this can be done, I will at least have a starting point.

Can this be done with a trigger or is there another module in SF that can do something similar?

Thank you!