I am looking to either download or create a navigation bar that has two levels of text. I want to communicate more information on the Navigation buttons but being restricted to one line of text is restricting this. There is noting in the gallery so I assume i'd need to build one, but my attempts have proven ineffective thus far. I can make a series of separate buttons with two lines of text but not a full navigation bar.

My last attempt on a live website ended up slightly breaking my Nav bar. Now when a mouse is hovered, two nav buttons highlight (on all pages except the 'Index' page). I can't seem to fix this, even with replacing the nav bar (https://www.oetc.ca)

Any ideas or instruction on how I might be able to create a two text line nav bar OR fix my current nav bar.
Thanks,