Option to make box titles bold

[befriendabacterium]

Is your feature request related to a problem? Please describe.
Bit difficult to read box content especially when have a lot of records (this is a problem with PRISMA diagrams generally, not just your version of them!)

Describe the solution you'd like
If could make box titles like 'Records identified from' bold, and maybe subtitles like 'Databases' italic or better spaced, might make things more readable.

Describe alternatives you've considered
NA

Additional context
NA