diff --git a/.gitmodules b/.gitmodules
index 5c0588bc..fe68f3d7 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -531,3 +531,6 @@
 [submodule "vendor/grammars/sass-textmate-bundle"]
 	path = vendor/grammars/sass-textmate-bundle
 	url = https://github.com/nathos/sass-textmate-bundle
+[submodule "vendor/grammars/carto-atom"]
+	path = vendor/grammars/carto-atom
+	url = https://github.com/yohanboniface/carto-atom
diff --git a/grammars.yml b/grammars.yml
index 8bfbf4dc..222859f1 100644
--- a/grammars.yml
+++ b/grammars.yml
@@ -136,6 +136,8 @@ vendor/grammars/c.tmbundle:
 - source.c.platform
 vendor/grammars/capnproto.tmbundle:
 - source.capnp
+vendor/grammars/carto-atom:
+- source.css.mss
 vendor/grammars/ceylon-sublimetext:
 - module.ceylon
 - source.ceylon
diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 9005eabb..d8cd6824 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -450,12 +450,13 @@ Cap'n Proto:
   ace_mode: text
 
 CartoCSS:
+  type: programming
   aliases:
   - Carto
   extensions:
   - .mss
   ace_mode: text
-  tm_scope: none
+  tm_scope: source.css.mss
 
 Ceylon:
   type: programming
diff --git a/script/convert-grammars b/script/convert-grammars
index 7f3a0ee9..4b16dff4 100755
--- a/script/convert-grammars
+++ b/script/convert-grammars
@@ -44,7 +44,7 @@ class DirectoryPackage
         path.split('/')[-2] == 'Syntaxes'
       when '.tmlanguage'
         true
-      when '.cson'
+      when '.cson', '.json'
         path.split('/')[-2] == 'grammars'
       else
         false
@@ -152,6 +152,8 @@ def load_grammar(path)
     cson = `"#{CSONC}" "#{path}"`
     raise "Failed to convert CSON grammar '#{path}': #{$?.to_s}" unless $?.success?
     JSON.parse(cson)
+  when '.json'
+    JSON.parse(File.read(path))
   else
     raise "Invalid document type #{path}"
   end
diff --git a/vendor/grammars/carto-atom b/vendor/grammars/carto-atom
new file mode 160000
index 00000000..8086625a
--- /dev/null
+++ b/vendor/grammars/carto-atom
@@ -0,0 +1 @@
+Subproject commit 8086625aa5deac4ccd7374644b89e715deec2f7f