diff --git a/Gemfile b/Gemfile
index 8cfdaea..3346727 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,7 +2,7 @@ ruby '>= 2.6.6'
 
 source "https://rubygems.org"
 
-gem "jekyll", "~> 3.9"
+gem "jekyll", "~> 4.2"
 
 gem "execjs", "2.7.0" # https://github.com/rails/execjs/issues/99
 gem "autoprefixer-rails"
diff --git a/Gemfile.lock b/Gemfile.lock
index 618a40e..73fc192 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -51,21 +51,23 @@ GEM
       typhoeus (~> 1.3)
       yell (~> 2.0)
     http_parser.rb (0.8.0)
-    i18n (0.9.5)
+    i18n (1.10.0)
       concurrent-ruby (~> 1.0)
-    jekyll (3.9.2)
+    jekyll (4.2.2)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
-      i18n (~> 0.7)
-      jekyll-sass-converter (~> 1.0)
+      i18n (~> 1.0)
+      jekyll-sass-converter (~> 2.0)
       jekyll-watch (~> 2.0)
-      kramdown (>= 1.17, < 3)
+      kramdown (~> 2.3)
+      kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
-      mercenary (~> 0.3.3)
+      mercenary (~> 0.4.0)
       pathutil (~> 0.9)
-      rouge (>= 1.7, < 4)
+      rouge (~> 3.0)
       safe_yaml (~> 1.0)
+      terminal-table (~> 2.0)
     jekyll-feed (0.16.0)
       jekyll (>= 3.7, < 5.0)
     jekyll-paginate-v2 (3.0.0)
@@ -75,8 +77,8 @@ GEM
     jekyll-sanity (1.6.0)
       jekyll (>= 3.1, < 5.0)
       pathutil (~> 0.16)
-    jekyll-sass-converter (1.5.2)
-      sass (~> 3.4)
+    jekyll-sass-converter (2.2.0)
+      sassc (> 2.0.1, < 3.0)
     jekyll-seo-tag (2.8.0)
       jekyll (>= 3.8, < 5.0)
     jekyll-sitemap (1.4.0)
@@ -94,7 +96,7 @@ GEM
     listen (3.7.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
-    mercenary (0.3.6)
+    mercenary (0.4.0)
     mini_portile2 (2.8.0)
     minitest (5.15.0)
     nokogiri (1.13.3)
@@ -113,21 +115,19 @@ GEM
     rexml (3.2.5)
     rouge (3.28.0)
     safe_yaml (1.0.5)
-    sass (3.7.4)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
     sassc (2.4.0)
       ffi (~> 1.9)
     sprockets (4.0.3)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
+    terminal-table (2.0.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
     thread_safe (0.3.6)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
     tzinfo (1.2.9)
       thread_safe (~> 0.1)
+    unicode-display_width (1.8.0)
     yell (2.2.2)
     zeitwerk (2.5.4)
 
@@ -138,7 +138,7 @@ DEPENDENCIES
   autoprefixer-rails
   execjs (= 2.7.0)
   html-proofer (~> 3.19)
-  jekyll (~> 3.9)
+  jekyll (~> 4.2)
   jekyll-assets!
   jekyll-feed (~> 0.15)
   jekyll-paginate-v2 (~> 3.0)