diff --git a/.github/workflows/bundle_size.yml b/.github/workflows/bundle_size.yml
new file mode 100644
index 00000000..ab1e30dc
--- /dev/null
+++ b/.github/workflows/bundle_size.yml
@@ -0,0 +1,26 @@
+name: CI
+on: [push]
+jobs:
+  ci:
+    name: CI
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@master
+
+      - name: Set up Node.js
+        uses: actions/setup-node@master
+        with:
+          node-version: 12
+
+      - name: Install dependencies
+        run: yarn
+
+      - name: CSS Lint
+        run: yarn stylelint && yarn stylelint -- --report-needless-disables
+
+      - name: Build
+        run: yarn dist
+
+      - name: Reporting bundle sizes
+        run: script/bundle-size-report.js --all
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8c393beb..e9a10063 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,9 +25,6 @@ jobs:
       - name: Test
         run: yarn test
 
-      - name: Prepublish
-        run: script/prepublish
-
       - name: Create .npmrc
         run: |
           cat << EOF > "$HOME/.npmrc"
diff --git a/.npmignore b/.npmignore
index 2803190a..c373e1b1 100644
--- a/.npmignore
+++ b/.npmignore
@@ -9,7 +9,5 @@ docs-test/
 lib/
 pages/
 script/
-# we ignore this because everything in src/ is copied out in script/prepublish
-src/
 static/
 tests/
diff --git a/package.json b/package.json
index 67520aea..b7d6da0d 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,6 @@
     "eslint": "eslint script deprecations.js lib .storybook",
     "eslint-docs": "eslint docs/{content,src,*.js}",
     "postpublish": "script/postpublish",
-    "prepublishOnly": "script/prepublish",
     "publish-storybook": "script/publish-storybook",
     "start": "npm run dev",
     "dev": "cd docs && npm install && npm run develop",
diff --git a/script/prepublish b/script/prepublish
deleted file mode 100755
index 4d9604c9..00000000
--- a/script/prepublish
+++ /dev/null
@@ -1,14 +0,0 @@
-#!/bin/bash
-set -e
-
-# generate the build directory
-npm run --silent dist
-
-# run the bundle size and selector diff reports
-script/run-reports
-
-files=$(git ls-files src | sed -e 's#^src/##' | sed -e 's#/.*$##' | sort -u)
-echo $files > publish-files.log
-cd src
-cp -rv $files ..
-cd -