Tasks

[x] remove the main concept titles from the top row (because they are easily mistaken as column headers)
[x] make it visually clearer which chunks(s) a hovering concept is mentioned in
[x] make bubble labels appear instantly when hovering (browser default tooltips are too slow)
[x] when clicking on a bubble, show information on that concept in the resource
[x] when hovering over a bubble, highlight the chunk(s) in which the concept is mentioned
[x] when hovering over a bubble, highlight the position(s) where the concept is explicitly mentioned
[x] ensure that the chunk highlights don't interfere with the position highlights
[x] highlight the position of the concept currently shown in the bubble popup

sahanbull / x5learn