diff --git a/package-lock.json b/package-lock.json
index f2d3176..23c99e8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,6 +9,7 @@
       "version": "4.0.1",
       "license": "MIT",
       "dependencies": {
+        "@asamuzakjp/css-color": "^1.0.4",
         "rrweb-cssom": "^0.6.0"
       },
       "devDependencies": {
@@ -50,6 +51,11 @@
         "node": ">=6.0.0"
       }
     },
+    "node_modules/@asamuzakjp/css-color": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/@asamuzakjp/css-color/-/css-color-1.0.4.tgz",
+      "integrity": "sha512-1F6N0WjGsL4ZmQ7PS+hVl2Bb6yaH3wvXpGLJHjaCoWqsowkI04e9I9KqU2Bbdv+O6RBYv8XrjkPObQixlQHveA=="
+    },
     "node_modules/@babel/code-frame": {
       "version": "7.23.5",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.23.5.tgz",
@@ -7790,6 +7796,11 @@
         "@jridgewell/trace-mapping": "^0.3.9"
       }
     },
+    "@asamuzakjp/css-color": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/@asamuzakjp/css-color/-/css-color-1.0.4.tgz",
+      "integrity": "sha512-1F6N0WjGsL4ZmQ7PS+hVl2Bb6yaH3wvXpGLJHjaCoWqsowkI04e9I9KqU2Bbdv+O6RBYv8XrjkPObQixlQHveA=="
+    },
     "@babel/code-frame": {
       "version": "7.23.5",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.23.5.tgz",
diff --git a/package.json b/package.json
index e041af8..eeef2cf 100644
--- a/package.json
+++ b/package.json
@@ -37,6 +37,7 @@
   ],
   "main": "./lib/CSSStyleDeclaration.js",
   "dependencies": {
+    "@asamuzakjp/css-color": "^1.0.4",
     "rrweb-cssom": "^0.6.0"
   },
   "devDependencies": {