more native KaTeX equations

[JurajLieskovsky]

Averaging multiple equations per paragraph I would like to insert equations with a syntax more similar to that of LaTeX (especially those inline). There are multiple guides (1,2,3) which describe how using "partials". I tried modifying hugo-book in the same manner (my fork) but I have run into some rendering issues (an example here with repo). Does anyone know what the solution might be?