Information on locations and categories

Information on locations:

Is it possible to use HTML markup? I have done so here https://datsys.org/map/ but after a while the markup goes away and does not show in the information box so the formatting is lost.

Also how do I make the information pop up lass wide, about 50% of the current width?

Also the map is for hotels that fall into different categories or filters. The vistor should be able to filter by any one of three categories or filters:

Must Have’s
Venue Type and/OR….
County

However when I set up categories they appear under the map as one list. Is it not possible to have something similar to this:

Must Have’s (one column) Venue Type (another column) County (another column)

So someone can chose and filter by any of or all of three varients?

The page I need help with: [log in to see the link]