Hi Dalibor,
As you have pointed out, in vanilla osTicket’s Ticket List, unanswered tickets (and tickets with a new reply) have a bold subject line. Which makes it really obvious.
But I also feel that it is a really unattractive solution. The bold text also steals too much attention away from tickets that have been answered, but are still important nevertheless.
That is why, years ago, I stopped using bold text in osTicket Awesome’s Ticket List and instead used this green icon to indicate that a ticket is unanswered or has a new reply:

I feel that this strikes the right balance of being obvious without being overbearing and ugly.
However, if you would like to restore osTicket’s default functionality of making the text bold, simply add the following to Admin Panel > Settings > Theme > Custom CSS:
table.list td div[style="font-weight:bold"] a {
font-weight: 600 !important;
}
After doing so your Ticket List will look like this:

