diff --git a/src/calibre/ebooks/oeb/transforms/subset.py b/src/calibre/ebooks/oeb/transforms/subset.py index 9b10aaad06..f85f786547 100644 --- a/src/calibre/ebooks/oeb/transforms/subset.py +++ b/src/calibre/ebooks/oeb/transforms/subset.py @@ -89,7 +89,7 @@ class SubsetFonts(object): except (IndexError, KeyError, AttributeError, TypeError, ValueError): val = None if q in {'src', 'font-family'} else default if q in {'font-weight', 'font-stretch', 'font-style'}: - val = val.lower() if val else val + val = unicode(val).lower() if (val or val == 0) else val if val == 'inherit': val = default if q == 'font-weight':