Change colon to point before subtitles

I would like to change in the published articles the colon appearing after the titles and before the subtitles for a point. How do I modify this?
Thank you

Hi @Ana,

It requires to modify a Smarty template or add custom Javascript code. Where you want to make the change? Is it article page? What OJS version are you using?

I’m using OJS 3.1.1. I want to make the change in every page where the titles and subtitles appear.