diff --git a/package-lock.json b/package-lock.json
index d022739..a5ac879 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4807,6 +4807,11 @@
       "integrity": "sha1-Z29us8OZl8LuGsOpJP1hJHSPV40=",
       "dev": true
     },
+    "core-js": {
+      "version": "3.6.5",
+      "resolved": "https://registry.npmjs.org/core-js/-/core-js-3.6.5.tgz",
+      "integrity": "sha512-vZVEEwZoIsI+vPEuoF9Iqf5H7/M3eeQqWlQnYa8FSKKePuYTf5MWnxb5SDAzCa60b3JBRS5g9b+Dq7b1y/RCrA=="
+    },
     "core-js-compat": {
       "version": "3.6.5",
       "resolved": "https://registry.npmjs.org/core-js-compat/-/core-js-compat-3.6.5.tgz",
diff --git a/package.json b/package.json
index 6a67b07..8ee98cb 100644
--- a/package.json
+++ b/package.json
@@ -15,6 +15,7 @@
   "devDependencies": {
     "@babel/cli": "^7.11.6",
     "@babel/plugin-transform-runtime": "^7.11.0",
+    "core-js": "^3.6.5",
     "cross-env": "^7.0.2",
     "dedent": "^0.7.0",
     "eslint": "^7.7.0",
diff --git a/packages/ggsmark/package.json b/packages/ggsmark/package.json
index 5576fd4..212f1c6 100644
--- a/packages/ggsmark/package.json
+++ b/packages/ggsmark/package.json
@@ -18,7 +18,7 @@
     "remark-text-alignment": "^0.4.0",
     "unified": "^9.2.0"
   },
-  "main": "dist/index.js",
+  "main": "src/index.js",
   "browser": "dist/index.js",
   "module": "dist/index.js",
   "scripts": {
diff --git a/packages/ggsmark/src/index.js b/packages/ggsmark/src/index.js
index 959a503..d311798 100644
--- a/packages/ggsmark/src/index.js
+++ b/packages/ggsmark/src/index.js
@@ -3,6 +3,7 @@ import markdown from 'remark-parse'
 import merge from 'deepmerge'
 import gh from 'hast-util-sanitize/lib/github'
 import sanitize from 'rehype-sanitize'
+import 'core-js'
 
 // Plugins
 import iframe from 'remark-iframes'
diff --git a/packages/remark-color-text/package.json b/packages/remark-color-text/package.json
index e65a435..00cba0a 100644
--- a/packages/remark-color-text/package.json
+++ b/packages/remark-color-text/package.json
@@ -6,7 +6,7 @@
     "remark"
   ],
   "license": "MIT",
-  "main": "dist/index.js",
+  "main": "src/index.js",
   "browser": "dist/index.js",
   "module": "dist/index.js",
   "scripts": {
diff --git a/packages/remark-color-text/src/index.js b/packages/remark-color-text/src/index.js
index 945df34..296734f 100644
--- a/packages/remark-color-text/src/index.js
+++ b/packages/remark-color-text/src/index.js
@@ -1,3 +1,5 @@
+import 'core-js'
+
 const C_NEWLINE = '\n'
 const C_NEWPARAGRAPH = '\n\n'
 
diff --git a/packages/remark-spoilers/package.json b/packages/remark-spoilers/package.json
index 6ea3e38..108f5f9 100644
--- a/packages/remark-spoilers/package.json
+++ b/packages/remark-spoilers/package.json
@@ -6,7 +6,7 @@
     "remark"
   ],
   "license": "MIT",
-  "main": "dist/index.js",
+  "main": "src/index.js",
   "browser": "dist/index.js",
   "module": "dist/index.js",
   "scripts": {
diff --git a/packages/remark-spoilers/src/index.js b/packages/remark-spoilers/src/index.js
index 123b7ee..d5a1e5a 100644
--- a/packages/remark-spoilers/src/index.js
+++ b/packages/remark-spoilers/src/index.js
@@ -1,3 +1,5 @@
+import 'core-js'
+
 const C_NEWLINE = '\n'
 const C_NEWPARAGRAPH = '\n\n'
 
diff --git a/packages/remark-text-alignment/package.json b/packages/remark-text-alignment/package.json
index 90771c4..8074ec9 100644
--- a/packages/remark-text-alignment/package.json
+++ b/packages/remark-text-alignment/package.json
@@ -9,7 +9,7 @@
   "dependencies": {
     "space-separated-tokens": "^1.1.5"
   },
-  "main": "dist/index.js",
+  "main": "src/index.js",
   "browser": "dist/index.js",
   "module": "dist/index.js",
   "scripts": {
diff --git a/packages/remark-text-alignment/src/index.js b/packages/remark-text-alignment/src/index.js
index 6a326cb..5129b13 100644
--- a/packages/remark-text-alignment/src/index.js
+++ b/packages/remark-text-alignment/src/index.js
@@ -1,4 +1,5 @@
 import spaceSeparated from 'space-separated-tokens'
+import 'core-js'
 
 const C_NEWLINE = '\n'
 const C_NEWPARAGRAPH = '\n\n'