diff --git a/AMPLIFY_DEPLOY.md b/AMPLIFY_DEPLOY.md
index 11f6df5..db2f48c 100644
--- a/AMPLIFY_DEPLOY.md
+++ b/AMPLIFY_DEPLOY.md
@@ -41,7 +41,12 @@ On the environment-variables screen, add the following. Required ones first:
 | `CIVI_BASE_URL` | e.g. `https://crm.fci.coop` |
 | `CIVI_API_KEY` | mark as **Secret** (eye icon on the value field) |
 | `CIVI_SITE_KEY` | mark as **Secret** |
-| `NODE_ENV` | `production` |
+
+Do **not** set `NODE_ENV=production` in the Amplify panel. Amplify and Next
+already set it correctly at runtime; setting it at build time causes
+`npm ci` to skip devDependencies, which breaks the Tailwind/PostCSS step.
+The `amplify.yml` in this repo guards against this with `--include=dev`,
+but it's cleaner not to set it at all.
 
 Optional, only if relevant:
 
diff --git a/amplify.yml b/amplify.yml
index 1615c3d..fee4650 100644
--- a/amplify.yml
+++ b/amplify.yml
@@ -5,7 +5,10 @@ applications:
         preBuild:
           commands:
             - nvm use $(cat .nvmrc) || nvm install $(cat .nvmrc)
-            - npm ci --cache .npm --prefer-offline
+            # --include=dev is required because the build needs PostCSS /
+            # Tailwind plugins which live in devDependencies; without it,
+            # NODE_ENV=production in the Amplify env causes npm to skip them.
+            - npm ci --include=dev --cache .npm --prefer-offline
         build:
           commands:
             - npm run build