Here a bit on Markdown .css styles, that can be found on the net and are free.. Previews were rendered in ReText (QWebKit); but they should work with spmdwe as well.
Homepage at RStudio markdown custom rendering; download rstudio/markdown · GitHub
markdown.css
Page here: borismus/markdown-preview · GitHub; original probably Github Markdown CSS - for Markdown Editor Preview — Gist.
markdown.css = "replaced the much-agonized-over css with that of GitHub.css from Mou.app"
Webpage markdown friendly css — Gist
screen.css
Download jasonm23/markdown-css-themes · GitHub; homepage (demo) at http://jasonm23.github.com/markdown-css-themes/
markdark.css = markdown1.css
markdown.css (lighter) = markdown3.css
markdown-alt.css
foghorn.css = markdown2.css
swiss.css = markdown4.css
markdown5.css
markdown6.css
Download simonlc/Markdown-CSS · GitHub; homepage at http://simon.lc/sites/markdown/:
Markdown CSS by Simon Laroche
This is a simple stylesheet for Markdown generated html. It is designed to work mobile devices, and also has a print style included. If you would like to make a change, or sumbit an issue, you can do so on github.
Homepage at http://kevinburke.bitbucket.org/markdowncss/ :
Markdown.css is better default styling for your Markdown files. It's heavily inspired by the Space WordPress theme. This page is itself a Markdown file using the
markdown.cssstylesheet. View the source code here.
ReText default with 12pt Times New Roman (for comparison):
The ReText PyQt4 application has three .css files in its /templates directory. These are more-less the same styles, just with different backgrounds: style_Blue.css (blue bckg), style_Default.css (gray bckg) and style_Simple.css (white bckg).
Diem 5.1 has markdown.css, but its quite boring (even with sed -i 's/.markdown //g' md-diemp.css).