From 86373bac9bf3020a691c268bd495de1781f117df Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 23 Apr 2022 07:11:12 +0530
Subject: [PATCH] Fix #1969981 [Conversion to PDF fails with "TypeError: '<='
 not supported between instances of 'str' and
 'float'"](https://bugs.launchpad.net/calibre/+bug/1969981)

---
 src/calibre/ebooks/oeb/transforms/flatcss.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/calibre/ebooks/oeb/transforms/flatcss.py b/src/calibre/ebooks/oeb/transforms/flatcss.py
index 11f36dd9a3..1d728a9a04 100644
--- a/src/calibre/ebooks/oeb/transforms/flatcss.py
+++ b/src/calibre/ebooks/oeb/transforms/flatcss.py
@@ -338,9 +338,9 @@ class CSSFlattener:
                 if '%' in cssdict[property]:
                     continue
                 value = style[property]
-                if value == 0:
+                if value == 0 or not isinstance(value, numbers.Number):
                     continue
-                elif value <= slineh:
+                if value <= slineh:
                     cssdict[property] = "%0.5fem" % (dlineh / fsize)
                 else:
                     try: