diff --git a/src/epub_converter/tag_css_style_converter.py b/src/epub_converter/tag_css_style_converter.py
index eb6bb73..1032d49 100644
--- a/src/epub_converter/tag_css_style_converter.py
+++ b/src/epub_converter/tag_css_style_converter.py
@@ -201,7 +201,7 @@ class TagStyleConverter:
                 # if we find styles that cannot be in <tag.name> -> wrap them in span
                 tag = BeautifulSoup(features="lxml").new_tag(f"{initial_tag.name}")
                 style = ""
-                possible_attrs_regexp = [re.compile(fr"{style}: *\w+;") for style in styles_can_be_in_tag]
+                possible_attrs_regexp = [re.compile(fr"({style}: *\w+;)") for style in styles_can_be_in_tag]
                 for possible_attr_regexp in possible_attrs_regexp:
                     has_style_attrs = re.search(
                         possible_attr_regexp, span_style)