diff --git a/assets/package-lock.json b/assets/package-lock.json
index ad8621002..4b39f7da0 100644
--- a/assets/package-lock.json
+++ b/assets/package-lock.json
@@ -54,7 +54,7 @@
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         "postcss": "^8.4.5",
         "postcss-cli": "^9.1.0",
-        "postcss-csso": "^5.0.1",
+        "postcss-csso": "^6.0.0",
         "postcss-flexbugs-fixes": "^5.0.2",
         "rollup": "^2.61.1",
         "rollup-plugin-handlebars-plus": "0.2.5",
@@ -2766,16 +2766,17 @@
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-      "resolved": "https://registry.npmjs.org/css-tree/-/css-tree-1.1.3.tgz",
-      "integrity": "sha512-tRpdppF7TRazZrjJ6v3stzv93qxRcSsFmW6cX0Zm2NVKpxE1WV1HblnghVv9TreireHkqI/VDEsfolRF1p6y7Q==",
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/css-tree/-/css-tree-2.0.4.tgz",
+      "integrity": "sha512-b4IS9ZUMtGBiNjzYbcj9JhYbyei99R3ai2CSxlu8GQDnoPA/P+NU85hAm0eKDc/Zp660rpK6tFJQ2OSdacMHVg==",
       "dev": true,
       "dependencies": {
-        "mdn-data": "2.0.14",
-        "source-map": "^0.6.1"
+        "mdn-data": "2.0.23",
+        "source-map-js": "^1.0.1"
       },
       "engines": {
-        "node": ">=8.0.0"
+        "node": "^10 || ^12.20.0 || ^14.13.0 || >=15.0.0",
+        "npm": ">=7.0.0"
       }
     },
     "node_modules/cssesc": {
@@ -2791,15 +2792,16 @@
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     "node_modules/csso": {
-      "version": "4.2.0",
-      "resolved": "https://registry.npmjs.org/csso/-/csso-4.2.0.tgz",
-      "integrity": "sha512-wvlcdIbf6pwKEk7vHj8/Bkc0B4ylXZruLvOgs9doS5eOsOpuodOV2zJChSpkp+pRpYQLQMeF04nr3Z68Sta9jA==",
+      "version": "5.0.2",
+      "resolved": "https://registry.npmjs.org/csso/-/csso-5.0.2.tgz",
+      "integrity": "sha512-llFAe1UfFHy38ziX+YrPMGkn5MxdjzYtz0drvgnjRY/tLPmBRxotYTGO51BsKe9voQA074pEb0udV+piXH4scQ==",
       "dev": true,
       "dependencies": {
-        "css-tree": "^1.1.2"
+        "css-tree": "~2.0.4"
       },
       "engines": {
-        "node": ">=8.0.0"
+        "node": "^10 || ^12.20.0 || ^14.13.0 || >=15.0.0",
+        "npm": ">=7.0.0"
       }
     },
     "node_modules/custom-event": {
@@ -7556,9 +7558,9 @@
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     },
     "node_modules/mdn-data": {
-      "version": "2.0.14",
-      "resolved": "https://registry.npmjs.org/mdn-data/-/mdn-data-2.0.14.tgz",
-      "integrity": "sha512-dn6wd0uw5GsdswPFfsgMp5NSB0/aDe6fK94YJV/AJDYXL6HVLWBsxeq7js7Ad+mU2K9LAlwpk6kN2D5mwCPVow==",
+      "version": "2.0.23",
+      "resolved": "https://registry.npmjs.org/mdn-data/-/mdn-data-2.0.23.tgz",
+      "integrity": "sha512-IonVb7pfla2U4zW8rc7XGrtgq11BvYeCxWN8HS+KFBnLDE7XDK9AAMVhRuG6fj9BBsjc69Fqsp6WEActEdNTDQ==",
       "dev": true
     },
     "node_modules/media-typer": {
@@ -9092,15 +9094,16 @@
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     },
     "node_modules/postcss-csso": {
-      "version": "5.0.1",
-      "resolved": "https://registry.npmjs.org/postcss-csso/-/postcss-csso-5.0.1.tgz",
-      "integrity": "sha512-TI99uhhJK2L5IQXPuyNcT3XV9bffSvDPmNpHi5f+tBq+R/01ucgLsUCcTDcVNqKMxO28klI6NwgjrHrM99x9KA==",
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/postcss-csso/-/postcss-csso-6.0.0.tgz",
+      "integrity": "sha512-LsrU+LVR0mNIYauoTEbYVC81i+yXcGWa9kqW6Lvm+gYUZTaNTJmJT6Dbv+fqT8gOnwXAH1RV+5RXvAVoRtwO+g==",
       "dev": true,
       "dependencies": {
-        "csso": "^4.0.2"
+        "csso": "^5.0.1"
       },
       "engines": {
-        "node": ">=10.12.0"
+        "node": "^12.20.0 || ^14.13.0 || >=15.0.0",
+        "npm": ">=7.0.0"
       },
       "peerDependencies": {
         "postcss": "^8.0.0"
@@ -14994,13 +14997,13 @@
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     "css-tree": {
-      "version": "1.1.3",
-      "resolved": "https://registry.npmjs.org/css-tree/-/css-tree-1.1.3.tgz",
-      "integrity": "sha512-tRpdppF7TRazZrjJ6v3stzv93qxRcSsFmW6cX0Zm2NVKpxE1WV1HblnghVv9TreireHkqI/VDEsfolRF1p6y7Q==",
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/css-tree/-/css-tree-2.0.4.tgz",
+      "integrity": "sha512-b4IS9ZUMtGBiNjzYbcj9JhYbyei99R3ai2CSxlu8GQDnoPA/P+NU85hAm0eKDc/Zp660rpK6tFJQ2OSdacMHVg==",
       "dev": true,
       "requires": {
-        "mdn-data": "2.0.14",
-        "source-map": "^0.6.1"
+        "mdn-data": "2.0.23",
+        "source-map-js": "^1.0.1"
       }
     },
     "cssesc": {
@@ -15010,12 +15013,12 @@
       "dev": true
     },
     "csso": {
-      "version": "4.2.0",
-      "resolved": "https://registry.npmjs.org/csso/-/csso-4.2.0.tgz",
-      "integrity": "sha512-wvlcdIbf6pwKEk7vHj8/Bkc0B4ylXZruLvOgs9doS5eOsOpuodOV2zJChSpkp+pRpYQLQMeF04nr3Z68Sta9jA==",
+      "version": "5.0.2",
+      "resolved": "https://registry.npmjs.org/csso/-/csso-5.0.2.tgz",
+      "integrity": "sha512-llFAe1UfFHy38ziX+YrPMGkn5MxdjzYtz0drvgnjRY/tLPmBRxotYTGO51BsKe9voQA074pEb0udV+piXH4scQ==",
       "dev": true,
       "requires": {
-        "css-tree": "^1.1.2"
+        "css-tree": "~2.0.4"
       }
     },
     "custom-event": {
@@ -18765,9 +18768,9 @@
       "integrity": "sha512-c4vLwYWyl+Ji+U43eU/G5FwxWd4ZH0ePUsFs5y0uwD9HUEFBXUQ1zUUan+78IpRD+y4pUfG0nAzNM292K7ItvA=="
     },
     "mdn-data": {
-      "version": "2.0.14",
-      "resolved": "https://registry.npmjs.org/mdn-data/-/mdn-data-2.0.14.tgz",
-      "integrity": "sha512-dn6wd0uw5GsdswPFfsgMp5NSB0/aDe6fK94YJV/AJDYXL6HVLWBsxeq7js7Ad+mU2K9LAlwpk6kN2D5mwCPVow==",
+      "version": "2.0.23",
+      "resolved": "https://registry.npmjs.org/mdn-data/-/mdn-data-2.0.23.tgz",
+      "integrity": "sha512-IonVb7pfla2U4zW8rc7XGrtgq11BvYeCxWN8HS+KFBnLDE7XDK9AAMVhRuG6fj9BBsjc69Fqsp6WEActEdNTDQ==",
       "dev": true
     },
     "media-typer": {
@@ -19932,12 +19935,12 @@
       }
     },
     "postcss-csso": {
-      "version": "5.0.1",
-      "resolved": "https://registry.npmjs.org/postcss-csso/-/postcss-csso-5.0.1.tgz",
-      "integrity": "sha512-TI99uhhJK2L5IQXPuyNcT3XV9bffSvDPmNpHi5f+tBq+R/01ucgLsUCcTDcVNqKMxO28klI6NwgjrHrM99x9KA==",
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/postcss-csso/-/postcss-csso-6.0.0.tgz",
+      "integrity": "sha512-LsrU+LVR0mNIYauoTEbYVC81i+yXcGWa9kqW6Lvm+gYUZTaNTJmJT6Dbv+fqT8gOnwXAH1RV+5RXvAVoRtwO+g==",
       "dev": true,
       "requires": {
-        "csso": "^4.0.2"
+        "csso": "^5.0.1"
       }
     },
     "postcss-flexbugs-fixes": {
diff --git a/assets/package.json b/assets/package.json
index c9030a962..0aec693b6 100644
--- a/assets/package.json
+++ b/assets/package.json
@@ -73,7 +73,7 @@
     "npm-run-all": "^4.1.5",
     "postcss": "^8.4.5",
     "postcss-cli": "^9.1.0",
-    "postcss-csso": "^5.0.1",
+    "postcss-csso": "^6.0.0",
     "postcss-flexbugs-fixes": "^5.0.2",
     "rollup": "^2.61.1",
     "rollup-plugin-handlebars-plus": "0.2.5",