This is the first post on Compass Rose. A digital garden in the loosest sense — an English garden with a couple of drip lines run over by a drunk mower, not a meticulously pruned one.
A quick check that KaTeX is wired up correctly. Inline math: $a^2 + b^2 = c^2$.
Block math:
$$ \sum_{n=1}^{k} \frac{1}{n^2} = \frac{\pi^2}{6} $$If both of those rendered as actual typeset math rather than literal dollar signs and backslashes, the math pipeline works.