The README.md file points to css file version 5.1.0,
"https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.5.1/katex.min.css"
The above version has little less line height issue,
if any higher version is used like 0.16.4 it breaks css and decreases line height further and collapses lines.
Tested with Block example.