diff --git a/build/postcss-combine-selectors.cjs b/build/postcss-combine-selectors.cjs
new file mode 100644
index 00000000..497504db
--- /dev/null
+++ b/build/postcss-combine-selectors.cjs
@@ -0,0 +1,88 @@
+const creator = () => {
+  return {
+    postcssPlugin: 'postcss-combine-selectors',
+    OnceExit(root) {
+      const rulesToCombine = new Map()
+      
+      root.walkRules(rule => {
+        if (isKeyframesRule(rule)) {
+          return
+        }
+        
+        const key = ruleKey(rule)
+        const existing = rulesToCombine.get(key)
+        
+        // Existing group:
+        // - add rule to the group
+        if (existing) {
+          existing.rules.push(rule)
+          return
+        }
+        
+        // New group:
+        // - first rule is the one we're going to combine into
+        // - create an empty slice for other rules to be added to
+        rulesToCombine.set(key, {
+          first: rule,
+          rules: []
+        })
+      })
+      
+      // Iterate over all groups
+      for (const { first, rules } of rulesToCombine.values()) {
+        // If there was only one rule for a given group, there's nothing to combine
+        if (rules.length === 0) {
+          continue
+        }
+        
+        // Append all contents of all subsequent rules to the first rule
+        for (const rule of rules) {
+          rule.each((child) => {
+            child.remove()
+            first.append(child)
+          })
+          
+          // Remove the now-empty rule
+          rule.remove()
+        }
+      }
+    },
+  }
+}
+
+/**
+* Construct a key that is specific to the AST ancestry of the rule.
+* Only rules with the same key can be combined.
+* 
+* @param {import('postcss').Rule} rule
+* @returns {string}
+*/
+function ruleKey(rule) {
+  let key = `[rule ${rule.selector}]`
+  
+  let ancestor = rule.parent
+  while (ancestor) {
+    if (ancestor.type === 'atrule') {
+      key = `[${ancestor.name} ${ancestor.params}]${key}`
+    } else if (ancestor.type === 'rule') {
+      key = `[rule ${ancestor.selector}]${key}`
+    } else if (ancestor.type === 'root') {
+      break
+    }
+    
+    ancestor = ancestor.parent
+  }
+  
+  return key
+}
+
+function isKeyframesRule(rule) {
+  if (rule.parent?.type === 'atrule' && rule.parent.name === 'keyframes') {
+    return true
+  }
+  
+  return false
+}
+
+module.exports = creator
+module.exports.postcss = true
diff --git a/package-lock.json b/package-lock.json
index c985b577..4e0659ae 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "open-props",
-  "version": "1.5.10",
+  "version": "1.5.16",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "open-props",
-      "version": "1.5.10",
+      "version": "1.5.16",
       "license": "MIT",
       "devDependencies": {
         "ava": "^3.15.0",
@@ -17,7 +17,6 @@
         "open-color": "^1.9.1",
         "postcss": "^8.3.9",
         "postcss-cli": "^8.3.1",
-        "postcss-combine-duplicated-selectors": "^10.0.3",
         "postcss-import": "^14.0.2",
         "postcss-preset-env": "6.7.x",
         "typescript": "^4.9.4"
@@ -3894,46 +3893,6 @@
         "postcss": "^8.2.15"
       }
     },
-    "node_modules/postcss-combine-duplicated-selectors": {
-      "version": "10.0.3",
-      "resolved": "https://registry.npmjs.org/postcss-combine-duplicated-selectors/-/postcss-combine-duplicated-selectors-10.0.3.tgz",
-      "integrity": "sha512-IP0BmwFloCskv7DV7xqvzDXqMHpwdczJa6ZvIW8abgHdcIHs9mCJX2ltFhu3EwA51ozp13DByng30+Ke+eIExA==",
-      "dev": true,
-      "dependencies": {
-        "postcss-selector-parser": "^6.0.4"
-      },
-      "engines": {
-        "node": "^10.0.0 || ^12.0.0 || >=14.0.0"
-      },
-      "peerDependencies": {
-        "postcss": "^8.1.0"
-      }
-    },
-    "node_modules/postcss-combine-duplicated-selectors/node_modules/cssesc": {
-      "version": "3.0.0",
-      "resolved": "https://registry.npmjs.org/cssesc/-/cssesc-3.0.0.tgz",
-      "integrity": "sha512-/Tb/JcjK111nNScGob5MNtsntNM1aCNUDipB/TkwZFhyDrrE47SOx/18wF2bbjgc3ZzCSKW1T5nt5EbFoAz/Vg==",
-      "dev": true,
-      "bin": {
-        "cssesc": "bin/cssesc"
-      },
-      "engines": {
-        "node": ">=4"
-      }
-    },
-    "node_modules/postcss-combine-duplicated-selectors/node_modules/postcss-selector-parser": {
-      "version": "6.0.6",
-      "resolved": "https://registry.npmjs.org/postcss-selector-parser/-/postcss-selector-parser-6.0.6.tgz",
-      "integrity": "sha512-9LXrvaaX3+mcv5xkg5kFwqSzSH1JIObIx51PrndZwlmznwXRfxMddDvo9gve3gVR8ZTKgoFDdWkbRFmEhT4PMg==",
-      "dev": true,
-      "dependencies": {
-        "cssesc": "^3.0.0",
-        "util-deprecate": "^1.0.2"
-      },
-      "engines": {
-        "node": ">=4"
-      }
-    },
     "node_modules/postcss-convert-values": {
       "version": "5.1.2",
       "resolved": "https://registry.npmjs.org/postcss-convert-values/-/postcss-convert-values-5.1.2.tgz",
@@ -9197,33 +9156,6 @@
         "postcss-value-parser": "^4.2.0"
       }
     },
-    "postcss-combine-duplicated-selectors": {
-      "version": "10.0.3",
-      "resolved": "https://registry.npmjs.org/postcss-combine-duplicated-selectors/-/postcss-combine-duplicated-selectors-10.0.3.tgz",
-      "integrity": "sha512-IP0BmwFloCskv7DV7xqvzDXqMHpwdczJa6ZvIW8abgHdcIHs9mCJX2ltFhu3EwA51ozp13DByng30+Ke+eIExA==",
-      "dev": true,
-      "requires": {
-        "postcss-selector-parser": "^6.0.4"
-      },
-      "dependencies": {
-        "cssesc": {
-          "version": "3.0.0",
-          "resolved": "https://registry.npmjs.org/cssesc/-/cssesc-3.0.0.tgz",
-          "integrity": "sha512-/Tb/JcjK111nNScGob5MNtsntNM1aCNUDipB/TkwZFhyDrrE47SOx/18wF2bbjgc3ZzCSKW1T5nt5EbFoAz/Vg==",
-          "dev": true
-        },
-        "postcss-selector-parser": {
-          "version": "6.0.6",
-          "resolved": "https://registry.npmjs.org/postcss-selector-parser/-/postcss-selector-parser-6.0.6.tgz",
-          "integrity": "sha512-9LXrvaaX3+mcv5xkg5kFwqSzSH1JIObIx51PrndZwlmznwXRfxMddDvo9gve3gVR8ZTKgoFDdWkbRFmEhT4PMg==",
-          "dev": true,
-          "requires": {
-            "cssesc": "^3.0.0",
-            "util-deprecate": "^1.0.2"
-          }
-        }
-      }
-    },
     "postcss-convert-values": {
       "version": "5.1.2",
       "resolved": "https://registry.npmjs.org/postcss-convert-values/-/postcss-convert-values-5.1.2.tgz",
diff --git a/package.json b/package.json
index e969dd07..8e084174 100644
--- a/package.json
+++ b/package.json
@@ -317,7 +317,6 @@
     "open-color": "^1.9.1",
     "postcss": "^8.3.9",
     "postcss-cli": "^8.3.1",
-    "postcss-combine-duplicated-selectors": "^10.0.3",
     "postcss-import": "^14.0.2",
     "postcss-preset-env": "6.7.x",
     "typescript": "^4.9.4"
diff --git a/postcss.config.cjs b/postcss.config.cjs
index 7ac657c9..5a74ce6d 100644
--- a/postcss.config.cjs
+++ b/postcss.config.cjs
@@ -1,7 +1,7 @@
 const postcssPresetEnv  = require('postcss-preset-env')
 const postcssImport     = require('postcss-import')
 const cssnano           = require('cssnano')
-const combineSelectors  = require('postcss-combine-duplicated-selectors')
+const combineSelectors  = require('./build/postcss-combine-selectors.cjs')
 
 const lib = process.env.npm_lifecycle_event