diff --git a/abattis-cantarell-fonts.spec b/abattis-cantarell-fonts.spec
index 1da8479..78fc66e 100644
--- a/abattis-cantarell-fonts.spec
+++ b/abattis-cantarell-fonts.spec
@@ -3,7 +3,7 @@
 
 Name: abattis-cantarell-fonts
 Version: 0.201
-Release: 3%{?dist}
+Release: 4%{?dist}
 Summary: Humanist sans serif font
 
 License: OFL
@@ -53,6 +53,9 @@ appstream-util validate-relax --nonet \
 %{_datadir}/metainfo/org.gnome.cantarell.metainfo.xml
 
 %changelog
+* Fri Jul 31 2020 Akira TAGOH <tagoh@redhat.com> - 0.201-4
+- Add the substitution rule for system-ui in fontconfig config.
+
 * Mon Jul 27 2020 Fedora Release Engineering <releng@fedoraproject.org> - 0.201-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_33_Mass_Rebuild
 
diff --git a/cantarell-fontconfig.conf b/cantarell-fontconfig.conf
index 2b3ab09..bc9f574 100644
--- a/cantarell-fontconfig.conf
+++ b/cantarell-fontconfig.conf
@@ -6,7 +6,22 @@
 
 -->
 <fontconfig>
+  <!-- Font substitution -->
+  <alias binding="same">
+    <family>system-ui</family>
+    <accept>
+      <family>Cantarell</family>
+    </accept>
+  </alias>
+
   <!-- Generic name assignment -->
+  <alias>
+    <family>Cantarell</family>
+    <default>
+      <family>system-ui</family>
+    </default>
+  </alias>
+
   <match target="pattern">
     <test qual="any" name="family">
       <string>Cantarell</string>