diff --git a/Gemfile b/Gemfile
index d2edfae..7269f7c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,7 +3,7 @@ source "https://rubygems.org"
 group :development do
   gem 'jekyll', '~> 1.5.1'
   gem 'sass','~> 3.2.17'
-  gem 'bootstrap-sass', '~> 3.1.1'
+  gem 'bootstrap-sass', '~> 3.4.1'
   gem 'white_castle', '~> 0.1.1'
   gem 'compass', '~> 0.12.4'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index ecee0f2..64afa52 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,9 +1,12 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    autoprefixer-rails (9.7.0)
+      execjs
     blankslate (2.1.2.4)
-    bootstrap-sass (3.1.1.0)
-      sass (~> 3.2)
+    bootstrap-sass (3.4.1)
+      autoprefixer-rails (>= 5.2.1)
+      sassc (>= 2.0.0)
     chunky_png (1.3.0)
     classifier (1.3.4)
       fast-stemmer (>= 1.0.0)
@@ -14,6 +17,7 @@ GEM
       chunky_png (~> 1.2)
       fssm (>= 0.2.7)
       sass (~> 3.2.17)
+    execjs (2.7.0)
     fast-stemmer (1.0.2)
     ffi (1.9.3)
     fssm (0.2.10)
@@ -49,6 +53,8 @@ GEM
     redcarpet (2.3.0)
     safe_yaml (1.0.1)
     sass (3.2.18)
+    sassc (2.2.1)
+      ffi (~> 1.9)
     toml (0.1.1)
       parslet (~> 1.5.0)
     white_castle (0.1.1)
@@ -58,7 +64,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  bootstrap-sass (~> 3.1.1)
+  bootstrap-sass (~> 3.4.1)
   compass (~> 0.12.4)
   jekyll (~> 1.5.1)
   sass (~> 3.2.17)