It seems my previous post got lost, so I am reposting (with little
changes), but without attaching the CSS file.
As example, by modifying line 5 of lyx.css from
font: x-small serif;
font: small sans-serif;
and then adding the line
to ".formula", the text is more web-styled (i.e. it uses sans-serif
fonts (formulas stay in serif) and fonts are a little larger.
This kind of modifications incorporate more screen-friendly display.
Compare it to the beamer output versus beamer notes.