Looking in more detail I understand that's meant to identify what is being typed.
However, there are a couple of issues:
* first of all, magenta might work well for some cards but not for others. I think any styling should be left to the person writing the card template.
* the argument to replaceFirst is just a string, so why are you quoting the [ and ] here?
* on the desktop, this is where the input text field will be showing so using just the dots might work: anyone else has suggestions?