[naisren]

extra css before conversion
body {
font-size: 0.8em;
}

WISH: stylesheet.css after conversion
.calibre {
display: block;
font-size: 0.8em;
margin-bottom: 0;
margin-left: 5pt;
margin-right: 5pt;
margin-top: 0;
page-break-before: always;
text-align: left
}

but in fact, stylesheet.css after conversion
.calibre {
display: block;
font-size: 1em;
margin-bottom: 0;
margin-left: 5pt;
margin-right: 5pt;
margin-top: 0;
page-break-before: always;
text-align: left
}

Why Calibre could not follow my purpose, just force the font-size as 1em?
1em in body tag is too big for me.