diff --git a/examples/classes.d2 b/examples/classes.d2
new file mode 100644
index 0000000..6ca1dcf
--- /dev/null
+++ b/examples/classes.d2
@@ -0,0 +1,34 @@
+direction: right
+classes: {
+  load balancer {
+    label: load\nbalancer
+    width: 100
+    height: 200
+    style: {
+      stroke-width: 0
+      fill: "#44C7B1"
+      shadow: true
+      border-radius: 5
+    }
+  }
+  unhealthy: {
+    style: {
+      fill: "#FE7070"
+      stroke: "#F69E03"
+    }
+  }
+}
+
+web traffic -> web lb
+web lb.class: load balancer
+
+web lb -> api1
+web lb -> api2
+web lb -> api3
+
+api2.class: unhealthy
+
+api1 -> cache lb
+api3 -> cache lb
+
+cache lb.class: load balancer
diff --git a/flake.lock b/flake.lock
index a6d455d..197a9a8 100644
--- a/flake.lock
+++ b/flake.lock
@@ -15,13 +15,28 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "locked": {
+        "lastModified": 1678901627,
+        "narHash": "sha256-U02riOqrKKzwjsxc/400XnElV+UtPUQWpANPlyazjH0=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "93a2b84fc4b70d9e089d029deacc3583435c2ed6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1669927173,
-        "narHash": "sha256-Z7rSKzC5OuWv5Q7RRNQPZb0jVJRJk0BJB6/fGZzaAIU=",
+        "lastModified": 1686737040,
+        "narHash": "sha256-R+JicNaI9mcxodtHkci894txjt4IMsfOnlAarA/r0xQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "9063accddd2e68dcc71032459a58399e977374c9",
+        "rev": "6d1d80a232a355a65dc4d3bfea1f108e8dac1340",
         "type": "github"
       },
       "original": {
@@ -31,10 +46,114 @@
         "type": "github"
       }
     },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1680005833,
+        "narHash": "sha256-BTMEjs+7hpmaP3n4hFVddrObMssANidP4EHgSpB0Lk0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "bd4e35e14a0130268c8f7b253a15e09d76ec95b7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_volar": {
+      "locked": {
+        "lastModified": 1682598396,
+        "narHash": "sha256-vheqVF2Cfa2+gpqeymDukd/7ecNp+eamV5Ll0S9ElQ8=",
+        "owner": "ehllie",
+        "repo": "nixpkgs",
+        "rev": "fc9529215f7ebd9ff5a5c498c60f781f0beeaedd",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ehllie",
+        "ref": "volar",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "poetry2nix": {
+      "inputs": {
+        "flake-utils": [
+          "tools",
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "tools",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1679994832,
+        "narHash": "sha256-LSsvtnkambdSWeNYT8wWTjSFVFyyIYxrI77QDfzUCHI=",
+        "owner": "nix-community",
+        "repo": "poetry2nix",
+        "rev": "2a72eea5fbccc262855c87e3032837f8465db385",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "poetry2nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "tools": "tools"
+      }
+    },
+    "tools": {
+      "inputs": {
+        "flake-utils": "flake-utils_2",
+        "nixpkgs": "nixpkgs_2",
+        "nixpkgs_volar": "nixpkgs_volar",
+        "poetry2nix": "poetry2nix",
+        "wd2": "wd2"
+      },
+      "locked": {
+        "lastModified": 1686758138,
+        "narHash": "sha256-aisJq5OU8qcvt82B6eSm8kOEukPAn7R5Qz9nIx1e7UQ=",
+        "ref": "refs/heads/main",
+        "rev": "32e27cb105f1ed5c7ee89032be6fb1a087eaa977",
+        "revCount": 44,
+        "type": "git",
+        "url": "https://git.pleshevski.ru/mynix/tools"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.pleshevski.ru/mynix/tools"
+      }
+    },
+    "wd2": {
+      "inputs": {
+        "flake-utils": [
+          "tools",
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "tools",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1680536082,
+        "narHash": "sha256-vGZxdADceCFjJAEuNYkpEvAPT8SD4Wd0cGSlhHTBDZk=",
+        "ref": "refs/heads/main",
+        "rev": "c4f9e3ea2679800dc04dc02957a8b460b2fc36cc",
+        "revCount": 22,
+        "type": "git",
+        "url": "https://git.pleshevski.ru/pleshevskiy/wd2"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.pleshevski.ru/pleshevskiy/wd2"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index d35a900..e6d9597 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,9 +2,10 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
     flake-utils.url = "github:numtide/flake-utils";
+    tools.url = "git+https://git.pleshevski.ru/mynix/tools";
   };
 
-  outputs = { self, nixpkgs, flake-utils, ... }:
+  outputs = { self, nixpkgs, flake-utils, tools, ... }:
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs { inherit system; };
@@ -13,6 +14,7 @@
         devShells.default = pkgs.mkShell {
           packages = with pkgs; [
             jq
+            tools.packages.${system}.d2
             nodejs-18_x
             tree-sitter
             nodePackages.eslint
diff --git a/grammar.js b/grammar.js
index b9987e6..49315ef 100644
--- a/grammar.js
+++ b/grammar.js
@@ -6,6 +6,7 @@ const PREC = {
   CONTAINER: 2,
   CONNECTION: 2,
   SHAPE: 3,
+  CLASSES: 4,
   IDENTIFIER: 0,
   ARROW: 0,
   ATTRIBUTE: 0,
@@ -33,6 +34,9 @@ module.exports = grammar({
     [$._container_block],
     [$._connection_block],
     [$._style_attribute_block],
+    [$._classes_block],
+    [$._classes_item_block],
+    [$.class_list],
   ],
 
   rules: {
@@ -44,6 +48,7 @@ module.exports = grammar({
         seq(
           choice(
             alias($._root_attribute, $.attribute),
+            $.classes,
             $.shape,
             $.container,
             $.connection
@@ -82,6 +87,57 @@ module.exports = grammar({
         "}"
       ),
 
+    // classes
+
+    classes: ($) =>
+      prec(
+        PREC.CLASSES,
+        seq(
+          $.keyword_classes,
+          choice(
+            optional(seq($.dot, $._classes_item)),
+            seq(
+              optional(seq($._colon, optional($.label))),
+              optional(alias($._classes_block, $.block))
+            )
+          )
+        )
+      ),
+
+    _classes_block: ($) =>
+      seq(
+        "{",
+        repeat(choice($._eol, seq($._classes_item, $._end))),
+        optional(seq($._classes_item, optional($._end))),
+        "}"
+      ),
+
+    _classes_item: ($) =>
+      seq(
+        $._class_name,
+        choice(
+          optional(seq($.dot, $._shape_attribute)),
+          seq(
+            optional(seq($._colon, optional($.label))),
+            optional(alias($._classes_item_block, $.class_block))
+          )
+        )
+      ),
+
+    _classes_item_block: ($) =>
+      seq(
+        "{",
+        repeat(choice($._eol, seq($._classes_item_attribute, $._end))),
+        optional(seq($._classes_item_attribute, optional($._end))),
+        "}"
+      ),
+
+    _classes_item_attribute: ($) =>
+      choice(
+        alias($._base_shape_attribute, $.attribute),
+        alias($._style_attribute, $.attribute)
+      ),
+
     // containers
 
     container: ($) =>
@@ -93,7 +149,7 @@ module.exports = grammar({
             seq($.dot, choice($.shape, $.container)),
             seq(
               optional(seq($._colon, optional($.label))),
-              optional(seq(alias($._container_block, $.block)))
+              optional(alias($._container_block, $.block))
             )
           )
         )
@@ -119,8 +175,8 @@ module.exports = grammar({
           $.shape_key,
           optional(
             choice(
-              seq($.dot, alias($._style_attribute, $.attribute)),
-              seq(optional(seq($._colon, choice($.label, $.text_block))))
+              seq($.dot, $._shape_attribute),
+              seq($._colon, choice($.label, $.text_block))
             )
           )
         )
@@ -168,7 +224,7 @@ module.exports = grammar({
             "label",
             "constraint",
             "icon",
-            "style",
+            $.keyword_style,
             $._common_style_attr_key,
             $._text_attr_key
           ),
@@ -177,11 +233,24 @@ module.exports = grammar({
       ),
 
     _shape_attribute: ($) =>
-      choice(
-        alias($._base_shape_attribute, $.attribute),
-        alias($._style_attribute, $.attribute)
+      alias(
+        choice($._class_attribute, $._base_shape_attribute, $._style_attribute),
+        $.attribute
       ),
 
+    _class_attribute: ($) =>
+      seq($.keyword_class, $._colon, choice($.class_list, $._class_name)),
+
+    class_list: ($) =>
+      seq(
+        "[",
+        repeat(choice($._eol, seq($._class_name, $._end))),
+        optional(seq($._class_name, optional($._end))),
+        "]"
+      ),
+
+    _class_name: ($) => alias($.shape_key, $.class_name),
+
     _base_shape_attribute: ($) =>
       seq(alias($._shape_attr_key, $.attr_key), $._colon, $.attr_value),
 
@@ -208,7 +277,7 @@ module.exports = grammar({
       prec(
         PREC.ATTRIBUTE,
         seq(
-          alias("style", $.attr_key),
+          $.keyword_style,
           choice(
             seq($.dot, alias($._inner_style_attribute, $.attribute)),
             seq($._colon, alias($._style_attribute_block, $.block))
@@ -245,6 +314,7 @@ module.exports = grammar({
         "grid-columns",
         "grid-rows"
       ),
+
     _style_attr_key: ($) => choice($._common_style_attr_key, "3d"),
 
     _common_style_attr_key: ($) =>
@@ -295,6 +365,10 @@ module.exports = grammar({
     _connection_arrowhead_attr_key: ($) =>
       choice("source-arrowhead", "target-arrowhead"),
 
+    keyword_classes: (_) => "classes",
+    keyword_class: (_) => "class",
+    keyword_style: (_) => "style",
+
     //
 
     label: ($) => choice($.string, $._unquoted_string),
diff --git a/queries/highlights.scm b/queries/highlights.scm
index b3f4cee..9484360 100644
--- a/queries/highlights.scm
+++ b/queries/highlights.scm
@@ -1,9 +1,15 @@
 ;-------------------------------------------------------------------------------
 
-(container_key) @constant
+(container_key) @string.special
 (shape_key) @variable
 (attr_key) @property
 (reserved) @error
+[
+  (keyword_style)
+  (keyword_classes)
+  (keyword_class)
+] @keyword
+(class_name) @constant
 
 ; Literals
 ;-------------------------------------------------------------------------------
@@ -37,6 +43,8 @@
 ] @punctuation.delimiter
 
 [
+  "["
+  "]"
   "{"
   "}"
   "|"
diff --git a/src/grammar.json b/src/grammar.json
index 08bf7eb..6a69750 100644
--- a/src/grammar.json
+++ b/src/grammar.json
@@ -30,6 +30,10 @@
                   "named": true,
                   "value": "attribute"
                 },
+                {
+                  "type": "SYMBOL",
+                  "name": "classes"
+                },
                 {
                   "type": "SYMBOL",
                   "name": "shape"
@@ -251,6 +255,339 @@
         }
       ]
     },
+    "classes": {
+      "type": "PREC",
+      "value": 4,
+      "content": {
+        "type": "SEQ",
+        "members": [
+          {
+            "type": "SYMBOL",
+            "name": "keyword_classes"
+          },
+          {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "CHOICE",
+                "members": [
+                  {
+                    "type": "SEQ",
+                    "members": [
+                      {
+                        "type": "SYMBOL",
+                        "name": "dot"
+                      },
+                      {
+                        "type": "SYMBOL",
+                        "name": "_classes_item"
+                      }
+                    ]
+                  },
+                  {
+                    "type": "BLANK"
+                  }
+                ]
+              },
+              {
+                "type": "SEQ",
+                "members": [
+                  {
+                    "type": "CHOICE",
+                    "members": [
+                      {
+                        "type": "SEQ",
+                        "members": [
+                          {
+                            "type": "SYMBOL",
+                            "name": "_colon"
+                          },
+                          {
+                            "type": "CHOICE",
+                            "members": [
+                              {
+                                "type": "SYMBOL",
+                                "name": "label"
+                              },
+                              {
+                                "type": "BLANK"
+                              }
+                            ]
+                          }
+                        ]
+                      },
+                      {
+                        "type": "BLANK"
+                      }
+                    ]
+                  },
+                  {
+                    "type": "CHOICE",
+                    "members": [
+                      {
+                        "type": "ALIAS",
+                        "content": {
+                          "type": "SYMBOL",
+                          "name": "_classes_block"
+                        },
+                        "named": true,
+                        "value": "block"
+                      },
+                      {
+                        "type": "BLANK"
+                      }
+                    ]
+                  }
+                ]
+              }
+            ]
+          }
+        ]
+      }
+    },
+    "_classes_block": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "{"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SYMBOL",
+                "name": "_eol"
+              },
+              {
+                "type": "SEQ",
+                "members": [
+                  {
+                    "type": "SYMBOL",
+                    "name": "_classes_item"
+                  },
+                  {
+                    "type": "SYMBOL",
+                    "name": "_end"
+                  }
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "SYMBOL",
+                  "name": "_classes_item"
+                },
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "SYMBOL",
+                      "name": "_end"
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                }
+              ]
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        },
+        {
+          "type": "STRING",
+          "value": "}"
+        }
+      ]
+    },
+    "_classes_item": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "_class_name"
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "CHOICE",
+              "members": [
+                {
+                  "type": "SEQ",
+                  "members": [
+                    {
+                      "type": "SYMBOL",
+                      "name": "dot"
+                    },
+                    {
+                      "type": "SYMBOL",
+                      "name": "_shape_attribute"
+                    }
+                  ]
+                },
+                {
+                  "type": "BLANK"
+                }
+              ]
+            },
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "SEQ",
+                      "members": [
+                        {
+                          "type": "SYMBOL",
+                          "name": "_colon"
+                        },
+                        {
+                          "type": "CHOICE",
+                          "members": [
+                            {
+                              "type": "SYMBOL",
+                              "name": "label"
+                            },
+                            {
+                              "type": "BLANK"
+                            }
+                          ]
+                        }
+                      ]
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                },
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "ALIAS",
+                      "content": {
+                        "type": "SYMBOL",
+                        "name": "_classes_item_block"
+                      },
+                      "named": true,
+                      "value": "class_block"
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    },
+    "_classes_item_block": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "{"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SYMBOL",
+                "name": "_eol"
+              },
+              {
+                "type": "SEQ",
+                "members": [
+                  {
+                    "type": "SYMBOL",
+                    "name": "_classes_item_attribute"
+                  },
+                  {
+                    "type": "SYMBOL",
+                    "name": "_end"
+                  }
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "SYMBOL",
+                  "name": "_classes_item_attribute"
+                },
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "SYMBOL",
+                      "name": "_end"
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                }
+              ]
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        },
+        {
+          "type": "STRING",
+          "value": "}"
+        }
+      ]
+    },
+    "_classes_item_attribute": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "ALIAS",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_base_shape_attribute"
+          },
+          "named": true,
+          "value": "attribute"
+        },
+        {
+          "type": "ALIAS",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_style_attribute"
+          },
+          "named": true,
+          "value": "attribute"
+        }
+      ]
+    },
     "container": {
       "type": "PREC",
       "value": 2,
@@ -327,18 +664,13 @@
                     "type": "CHOICE",
                     "members": [
                       {
-                        "type": "SEQ",
-                        "members": [
-                          {
-                            "type": "ALIAS",
-                            "content": {
-                              "type": "SYMBOL",
-                              "name": "_container_block"
-                            },
-                            "named": true,
-                            "value": "block"
-                          }
-                        ]
+                        "type": "ALIAS",
+                        "content": {
+                          "type": "SYMBOL",
+                          "name": "_container_block"
+                        },
+                        "named": true,
+                        "value": "block"
                       },
                       {
                         "type": "BLANK"
@@ -464,46 +796,28 @@
                         "name": "dot"
                       },
                       {
-                        "type": "ALIAS",
-                        "content": {
-                          "type": "SYMBOL",
-                          "name": "_style_attribute"
-                        },
-                        "named": true,
-                        "value": "attribute"
+                        "type": "SYMBOL",
+                        "name": "_shape_attribute"
                       }
                     ]
                   },
                   {
                     "type": "SEQ",
                     "members": [
+                      {
+                        "type": "SYMBOL",
+                        "name": "_colon"
+                      },
                       {
                         "type": "CHOICE",
                         "members": [
                           {
-                            "type": "SEQ",
-                            "members": [
-                              {
-                                "type": "SYMBOL",
-                                "name": "_colon"
-                              },
-                              {
-                                "type": "CHOICE",
-                                "members": [
-                                  {
-                                    "type": "SYMBOL",
-                                    "name": "label"
-                                  },
-                                  {
-                                    "type": "SYMBOL",
-                                    "name": "text_block"
-                                  }
-                                ]
-                              }
-                            ]
+                            "type": "SYMBOL",
+                            "name": "label"
                           },
                           {
-                            "type": "BLANK"
+                            "type": "SYMBOL",
+                            "name": "text_block"
                           }
                         ]
                       }
@@ -704,8 +1018,8 @@
                 "value": "icon"
               },
               {
-                "type": "STRING",
-                "value": "style"
+                "type": "SYMBOL",
+                "name": "keyword_style"
               },
               {
                 "type": "SYMBOL",
@@ -723,28 +1037,129 @@
       ]
     },
     "_shape_attribute": {
-      "type": "CHOICE",
-      "members": [
-        {
-          "type": "ALIAS",
-          "content": {
+      "type": "ALIAS",
+      "content": {
+        "type": "CHOICE",
+        "members": [
+          {
+            "type": "SYMBOL",
+            "name": "_class_attribute"
+          },
+          {
             "type": "SYMBOL",
             "name": "_base_shape_attribute"
           },
-          "named": true,
-          "value": "attribute"
-        },
-        {
-          "type": "ALIAS",
-          "content": {
+          {
             "type": "SYMBOL",
             "name": "_style_attribute"
-          },
-          "named": true,
-          "value": "attribute"
+          }
+        ]
+      },
+      "named": true,
+      "value": "attribute"
+    },
+    "_class_attribute": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "keyword_class"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_colon"
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SYMBOL",
+              "name": "class_list"
+            },
+            {
+              "type": "SYMBOL",
+              "name": "_class_name"
+            }
+          ]
         }
       ]
     },
+    "class_list": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "["
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SYMBOL",
+                "name": "_eol"
+              },
+              {
+                "type": "SEQ",
+                "members": [
+                  {
+                    "type": "SYMBOL",
+                    "name": "_class_name"
+                  },
+                  {
+                    "type": "SYMBOL",
+                    "name": "_end"
+                  }
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "SYMBOL",
+                  "name": "_class_name"
+                },
+                {
+                  "type": "CHOICE",
+                  "members": [
+                    {
+                      "type": "SYMBOL",
+                      "name": "_end"
+                    },
+                    {
+                      "type": "BLANK"
+                    }
+                  ]
+                }
+              ]
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        },
+        {
+          "type": "STRING",
+          "value": "]"
+        }
+      ]
+    },
+    "_class_name": {
+      "type": "ALIAS",
+      "content": {
+        "type": "SYMBOL",
+        "name": "shape_key"
+      },
+      "named": true,
+      "value": "class_name"
+    },
     "_base_shape_attribute": {
       "type": "SEQ",
       "members": [
@@ -823,13 +1238,8 @@
         "type": "SEQ",
         "members": [
           {
-            "type": "ALIAS",
-            "content": {
-              "type": "STRING",
-              "value": "style"
-            },
-            "named": true,
-            "value": "attr_key"
+            "type": "SYMBOL",
+            "name": "keyword_style"
           },
           {
             "type": "CHOICE",
@@ -1264,6 +1674,18 @@
         }
       ]
     },
+    "keyword_classes": {
+      "type": "STRING",
+      "value": "classes"
+    },
+    "keyword_class": {
+      "type": "STRING",
+      "value": "class"
+    },
+    "keyword_style": {
+      "type": "STRING",
+      "value": "style"
+    },
     "label": {
       "type": "CHOICE",
       "members": [
@@ -1591,6 +2013,15 @@
     ],
     [
       "_style_attribute_block"
+    ],
+    [
+      "_classes_block"
+    ],
+    [
+      "_classes_item_block"
+    ],
+    [
+      "class_list"
     ]
   ],
   "precedences": [],
diff --git a/src/node-types.json b/src/node-types.json
index 18b88b5..45b6b0d 100644
--- a/src/node-types.json
+++ b/src/node-types.json
@@ -69,10 +69,26 @@
           "type": "block",
           "named": true
         },
+        {
+          "type": "class_list",
+          "named": true
+        },
+        {
+          "type": "class_name",
+          "named": true
+        },
         {
           "type": "dot",
           "named": true
         },
+        {
+          "type": "keyword_class",
+          "named": true
+        },
+        {
+          "type": "keyword_style",
+          "named": true
+        },
         {
           "type": "label",
           "named": true
@@ -92,6 +108,14 @@
           "type": "attribute",
           "named": true
         },
+        {
+          "type": "class_block",
+          "named": true
+        },
+        {
+          "type": "class_name",
+          "named": true
+        },
         {
           "type": "connection",
           "named": true
@@ -100,6 +124,14 @@
           "type": "container",
           "named": true
         },
+        {
+          "type": "dot",
+          "named": true
+        },
+        {
+          "type": "label",
+          "named": true
+        },
         {
           "type": "shape",
           "named": true
@@ -112,6 +144,94 @@
     "named": true,
     "fields": {}
   },
+  {
+    "type": "class_block",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "attribute",
+          "named": true
+        }
+      ]
+    }
+  },
+  {
+    "type": "class_list",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "class_name",
+          "named": true
+        }
+      ]
+    }
+  },
+  {
+    "type": "class_name",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "escape_sequence",
+          "named": true
+        },
+        {
+          "type": "string",
+          "named": true
+        }
+      ]
+    }
+  },
+  {
+    "type": "classes",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": true,
+      "types": [
+        {
+          "type": "attribute",
+          "named": true
+        },
+        {
+          "type": "block",
+          "named": true
+        },
+        {
+          "type": "class_block",
+          "named": true
+        },
+        {
+          "type": "class_name",
+          "named": true
+        },
+        {
+          "type": "dot",
+          "named": true
+        },
+        {
+          "type": "keyword_classes",
+          "named": true
+        },
+        {
+          "type": "label",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "connection",
     "named": true,
@@ -287,6 +407,10 @@
           "type": "attribute",
           "named": true
         },
+        {
+          "type": "classes",
+          "named": true
+        },
         {
           "type": "connection",
           "named": true
@@ -364,6 +488,14 @@
     "type": ";",
     "named": false
   },
+  {
+    "type": "[",
+    "named": false
+  },
+  {
+    "type": "]",
+    "named": false
+  },
   {
     "type": "animated",
     "named": false
@@ -460,6 +592,18 @@
     "type": "italic",
     "named": false
   },
+  {
+    "type": "keyword_class",
+    "named": true
+  },
+  {
+    "type": "keyword_classes",
+    "named": true
+  },
+  {
+    "type": "keyword_style",
+    "named": true
+  },
   {
     "type": "label",
     "named": false
diff --git a/src/parser.c b/src/parser.c
index e9074d9..f80d5ff 100644
Binary files a/src/parser.c and b/src/parser.c differ
diff --git a/test/corpus/attributes.txt b/test/corpus/attributes.txt
index 6e580a6..5e98b4f 100644
--- a/test/corpus/attributes.txt
+++ b/test/corpus/attributes.txt
@@ -62,18 +62,18 @@ foo.style.text-transform: uppercase
 --------------------------------------------------------------------------------
 
 (source_file
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (float)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (integer)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (integer)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (integer)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (boolean)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (boolean)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (boolean)))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value))))
-  (shape (shape_key) (dot) (attribute (attr_key) (dot) (attribute (attr_key) (attr_value))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (float)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (integer)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (integer)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (integer)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (boolean)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (boolean)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (boolean)))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value))))
+  (shape (shape_key) (dot) (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value))))
 )
 
 ================================================================================
@@ -100,7 +100,7 @@ foo.style: {
   (shape
     (shape_key) (dot)
     (attribute
-      (attr_key)
+      (keyword_style)
       (block
         (attribute (attr_key) (attr_value (float)))
         (attribute (attr_key) (attr_value))
@@ -174,17 +174,17 @@ foo: {
   (container
     (container_key)
     (block
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (float))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value)))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value)))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (integer))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (integer))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (integer))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value)))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (boolean))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (boolean))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value (boolean))))
-      (attribute (attr_key) (dot) (attribute (attr_key) (attr_value)))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (float))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value)))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value)))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (integer))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (integer))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (integer))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value)))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (boolean))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (boolean))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value (boolean))))
+      (attribute (keyword_style) (dot) (attribute (attr_key) (attr_value)))
     )
   )
 )
@@ -215,7 +215,7 @@ foo: {
     (container_key)
     (block
       (attribute
-        (attr_key)
+        (keyword_style)
         (block
           (attribute (attr_key) (attr_value (float)))
           (attribute (attr_key) (attr_value))
@@ -262,7 +262,7 @@ foo -> bar: {
     (shape_key)
     (block
       (attribute
-        (attr_key)
+        (keyword_style)
         (block
           (attribute (attr_key) (attr_value (float)))
           (attribute (attr_key) (attr_value))
@@ -367,7 +367,7 @@ foo -> bar: {
         (attr_key)
         (block
           (attribute
-            (attr_key)
+            (keyword_style)
             (block
               (attribute (attr_key) (attr_value (float)))
               (attribute (attr_key) (attr_value))
@@ -436,7 +436,7 @@ foo.style: {opacity: 0.5; fill: red}
   (shape
     (shape_key) (dot)
     (attribute
-      (attr_key)
+      (keyword_style)
       (block
         (attribute (attr_key) (attr_value (float)))
         (attribute (attr_key) (attr_value))
diff --git a/test/corpus/classes.txt b/test/corpus/classes.txt
new file mode 100644
index 0000000..a840f96
--- /dev/null
+++ b/test/corpus/classes.txt
@@ -0,0 +1,198 @@
+================================================================================
+Declare empty classes keyword in the root
+================================================================================
+classes
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (classes (keyword_classes))
+)
+
+================================================================================
+Declare classes block with item block
+================================================================================
+classes: {
+  foo: {
+    style: {
+      fill: "#44C7B1"
+    }
+  }
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (classes
+    (keyword_classes)
+    (block
+      (class_name)
+      (class_block
+        (attribute
+          (keyword_style)
+          (block
+            (attribute
+              (attr_key)
+              (attr_value
+                (string (string_fragment))
+              )
+            )
+          )
+        )
+      )
+    )
+  )
+)
+
+================================================================================
+Declare classes block with item inline
+================================================================================
+classes: {
+  foo.style: {
+    fill: "#44C7B1"
+  }
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (classes
+    (keyword_classes)
+    (block
+      (class_name)
+      (dot)
+      (attribute
+        (keyword_style)
+        (block
+          (attribute
+            (attr_key)
+            (attr_value
+              (string (string_fragment))
+            )
+          )
+        )
+      )
+    )
+  )
+)
+
+================================================================================
+Declare classes inline with item inline
+================================================================================
+classes.foo.style: {
+  fill: "#44C7B1"
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (classes
+    (keyword_classes)
+    (dot)
+    (class_name)
+    (dot)
+    (attribute
+      (keyword_style)
+      (block
+        (attribute
+          (attr_key)
+          (attr_value
+            (string (string_fragment))
+          )
+        )
+      )
+    )
+  )
+)
+
+================================================================================
+Declare classes inline with item block
+================================================================================
+classes.foo: {
+  style: {
+    fill: "#44C7B1"
+  }
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (classes
+    (keyword_classes)
+    (dot)
+    (class_name)
+    (class_block
+      (attribute
+        (keyword_style)
+        (block
+          (attribute
+            (attr_key)
+            (attr_value
+              (string (string_fragment))
+            )
+          )
+        )
+      )
+    )
+  )
+)
+
+================================================================================
+Declare shape with a class
+================================================================================
+foo.class: biz
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (shape
+    (shape_key)
+    (dot)
+    (attribute
+      (keyword_class)
+      (class_name)
+    )
+  )
+)
+
+================================================================================
+Declare shape with many classes
+================================================================================
+foo.class: [biz; baz]
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (shape
+    (shape_key)
+    (dot)
+    (attribute
+      (keyword_class)
+      (class_list
+        (class_name)
+        (class_name)
+      )
+    )
+  )
+)
+
+================================================================================
+Declare a class in the container
+================================================================================
+foo: {
+  class: biz
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (container
+    (container_key)
+    (block
+      (attribute
+        (keyword_class)
+        (class_name)
+      )
+    )
+  )
+)
diff --git a/test/highlight/attribute.d2 b/test/highlight/attribute.d2
index 3dfd5a2..c9187c1 100644
--- a/test/highlight/attribute.d2
+++ b/test/highlight/attribute.d2
@@ -10,7 +10,7 @@ shape: oval
 
 baaaz.style: {
   # <- variable
-  #   ^ property
+  #   ^ keyword
   fill: red
   # <- property
   #     ^ string
@@ -22,12 +22,13 @@ foo: Label {
   #      ^ string
 
   style.fill: red;
-  # <- property
+  # <- keyword
   #     ^ property 
 }
 
 foo: {
   style: {
+  # <- keyword
     opacity: 0.5
     #        ^ float
     fill: red
@@ -54,6 +55,6 @@ foo: Label {
   #     ^ string
 
   style.fill: red
-  # <- property
+  # <- keyword
   #     ^ property 
 }
diff --git a/test/highlight/classes.d2 b/test/highlight/classes.d2
new file mode 100644
index 0000000..5f24a74
--- /dev/null
+++ b/test/highlight/classes.d2
@@ -0,0 +1,40 @@
+classes: {
+# <- keyword
+#      ^ punctuation.delimiter
+#        ^ punctuation.bracket
+  load balancer {
+    label: load\nbalancer
+    width: 100
+    height: 200
+    style: {
+      stroke-width: 0
+      fill: "#44C7B1"
+      shadow: true
+      border-radius: 5
+    }
+  }
+  unhealthy: {
+    style: {
+      fill: "#FE7070"
+      stroke: "#F69E03"
+    }
+  }
+}
+
+web traffic -> web lb
+web lb.class: load balancer
+# <- variable
+#     ^ punctuation.delimiter
+#      ^ keyword
+#           ^ punctuation.delimiter
+
+web lb -> api1
+web lb -> api2
+web lb -> api3
+
+api2.class: unhealthy
+
+api1 -> cache lb
+api3 -> cache lb
+
+cache lb.class: load balancer