I've been using Lichess to aid my studies and as such I typically enter tactical positions by theme (skewers, deflection, pins etc.) however I have to create a chapter per position. Would it be able to organise chapters so that they can be modelled as containers for multiple positions? I imagine having a chapter representing each theme and having multiple positions contained by the chapter. I think the easiest way I can think of it is to have nested chapters... this would provide a high degree of flexibility in modelling studies.