Change of matched bracket styling #398

Summary

I want to see brackets more clearly.
The a bracket and its matching pair are highlighted by a red underline.
I find this difficult to see.
I would like to have the whole character hightlighted, or to be able to change the highlight effect.

Describe alternatives you've considered

I have looked for where to find the css for this bracket highlighting effect.
I have used developer tools to find how highlights are implemented.

Additional context

None