diff --git a/Gemfile.lock b/Gemfile.lock
index 35b3ff8..5c95ed3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,8 +1,8 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.9.0)
+      public_suffix (>= 2.0.2, < 8.0)
     arr-pm (0.0.10)
       cabin (> 0)
     asciidoctor (2.0.13)
@@ -23,7 +23,7 @@ GEM
     coderay (1.1.3)
     concurrent-ruby (1.1.8)
     connection_pool (2.2.5)
-    css_parser (1.9.0)
+    css_parser (1.22.0)
       addressable
     descriptive_statistics (2.5.1)
     domain_name (0.5.20190701)
@@ -38,6 +38,10 @@ GEM
       rubyzip (~> 2.3)
       seven_zip_ruby (~> 1.0)
       thor (~> 1.0)
+    expressir (0.2.27)
+      nokogiri (~> 1.10)
+      rice (~> 3)
+      thor (~> 1.0)
     expressir (0.2.27-x86_64-darwin)
       nokogiri (~> 1.10)
       thor (~> 1.0)
@@ -56,6 +60,8 @@ GEM
       ffi (~> 1.0)
     ffi-libarchive-binary (0.2.3-x86_64-darwin)
       ffi-libarchive (~> 1.0)
+    ffi-libarchive-binary (0.2.3-x86_64-linux)
+      ffi-libarchive (~> 1.0)
     fontist (1.8.12)
       down (~> 5.0)
       excavate (~> 0.1)
@@ -285,7 +291,7 @@ GEM
     pry (0.14.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    public_suffix (4.0.6)
+    public_suffix (7.0.5)
     rake (13.0.3)
     rchardet (1.8.0)
     relaton (1.7.7)
@@ -374,6 +380,7 @@ GEM
     reverse_markdown (1.4.0)
       nokogiri
     rexml (3.2.5)
+    rice (3.0.0)
     roman-numerals (0.3.0)
     rsec (1.0.0)
     ruby-graphviz (1.2.5)
@@ -425,6 +432,7 @@ GEM
 
 PLATFORMS
   x86_64-darwin-19
+  x86_64-linux
 
 DEPENDENCIES
   metanorma-cli