just the page text?
there is no actual style for it in style.css of twenty ten; the font is inherited from:
/* =Fonts
-------------------------------------------------------------- */
body,
input,
textarea,
.page-title span,
.pingback a.url {
font-family: Georgia, "Bitstream Charter", serif;
}
you could make a new style, and add it to style.css, for instance:
.page .hentry { font-family: Georgia, "Bitstream Charter", serif; }
btw:
twenty ten as the default theme of wp3 will be overwritten with the next upgrade of wordpress – with it, all your modifications will be lost.
therefore it is recommended to consider making a child theme: https://codex.www.ads-software.com/Child_Themes
