diff --git a/package-lock.json b/package-lock.json
index 4ff116b..fb60b33 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -803,20 +803,12 @@
       }
     },
     "clean-css": {
-      "version": "4.2.3",
-      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-4.2.3.tgz",
-      "integrity": "sha512-VcMWDN54ZN/DS+g58HYL5/n4Zrqe8vHJpGA8KdgUXFU4fuP/aHNw8eld9SyEIyabIMJX/0RaY/fplOo5hYLSFA==",
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-5.0.1.tgz",
+      "integrity": "sha512-F1zAGOowUCg8yxT0O4UR+nmbMauf3YwbiUS60CPxpzJU7ulpamGzQomFrJSK4w/HqHtMmQKSHJUNue+dQQYQdg==",
       "dev": true,
       "requires": {
         "source-map": "~0.6.0"
-      },
-      "dependencies": {
-        "source-map": {
-          "version": "0.6.1",
-          "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
-          "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==",
-          "dev": true
-        }
       }
     },
     "cli-cursor": {
@@ -1851,6 +1843,15 @@
         "uglify-js": "^3.5.1"
       },
       "dependencies": {
+        "clean-css": {
+          "version": "4.2.3",
+          "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-4.2.3.tgz",
+          "integrity": "sha512-VcMWDN54ZN/DS+g58HYL5/n4Zrqe8vHJpGA8KdgUXFU4fuP/aHNw8eld9SyEIyabIMJX/0RaY/fplOo5hYLSFA==",
+          "dev": true,
+          "requires": {
+            "source-map": "~0.6.0"
+          }
+        },
         "source-map": {
           "version": "0.6.1",
           "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
@@ -3188,6 +3189,23 @@
           "integrity": "sha1-m7UwTS4LVmmLLHWLCKPqqdqlijk=",
           "dev": true
         },
+        "clean-css": {
+          "version": "4.2.3",
+          "resolved": "https://registry.npmjs.org/clean-css/-/clean-css-4.2.3.tgz",
+          "integrity": "sha512-VcMWDN54ZN/DS+g58HYL5/n4Zrqe8vHJpGA8KdgUXFU4fuP/aHNw8eld9SyEIyabIMJX/0RaY/fplOo5hYLSFA==",
+          "dev": true,
+          "requires": {
+            "source-map": "~0.6.0"
+          },
+          "dependencies": {
+            "source-map": {
+              "version": "0.6.1",
+              "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
+              "integrity": "sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==",
+              "dev": true
+            }
+          }
+        },
         "cliui": {
           "version": "2.1.0",
           "resolved": "https://registry.npmjs.org/cliui/-/cliui-2.1.0.tgz",
diff --git a/package.json b/package.json
index 2705cc0..0479894 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
     "@11ty/eleventy": "^0.11.1",
     "@11ty/eleventy-plugin-syntaxhighlight": "^3.0.6",
     "all-contributors-cli": "^6.19.0",
-    "clean-css": "^4.2.3",
+    "clean-css": "^5.0.1",
     "html-minifier": "^4.0.0",
     "luxon": "^1.25.0",
     "markdown-it": "^12.0.4",