[Phil_C]

This CSS works for me when I format a book in calibre:

@font-face {
 font-family: GeorgiaEInk15;
 font-weight: normal;
 font-style: normal;
 src: url(res:///Data/fonts/GeorgiaEInk15.ttf);
}
@font-face {
 font-family: GeorgiaEInk15;
 font-weight: bold;
 font-style: normal;
 src: url(res:///Data/fonts/GeorgiaEInk15Bold.ttf);
}
@font-face {
 font-family: GeorgiaEInk15;
 font-weight: normal;
 font-style: italic;
 src: url(res:///Data/fonts/GeorgiaEInk15Italic.ttf);
}
@font-face {
 font-family: GeorgiaEInk15;
 font-weight: bold;
 font-style: italic;
 src: url(res:///Data/fonts/GeorgiaEInk15BoldItalic.ttf);
}
body {
 font-family: GeorgiaEInk15;
 widows: 0;
 orphans: 0;
}

The font files are in the "fonts" folder in the root of the "READER" drive (not the "SETTINGS" drive).

I do not know if the drive name or the path is the same on the Japanese version of the 350.