Markdown renderer: markdeep, MuBoard, TeXMe
Here are some tools, which help you write simple text in markdown and render it in the browser. They all support Latex Math / MathJax - accessible math in the browser.
Markdeep
Markdeep supports Markdown, Math, code, diagrams, … There are different purpose templates (apidoc, article, blog, paper) in css. You can create more on your own, like I did for this website.
https://casual-effects.com/markdeep/
MuBoard
Muboard is a for writing mathematics in latex with support for Markdown and LaTeX
https://github.com/susam/muboard
TeXMe
Texme supports Markdown with Math in Tex