diff --git a/Dockerfile b/Dockerfile
index d6eac3e..9e620af 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,3 +1,3 @@
-FROM nginx
+FROM nginx:alpine
 
 COPY nginx.conf /etc/nginx/nginx.conf
diff --git a/README.md b/README.md
index 3efc689..f41da37 100644
--- a/README.md
+++ b/README.md
@@ -85,7 +85,7 @@ sudo service network-manager restart
 
 For more information see [here](https://askubuntu.com/q/1167177/920103).
 
-## Firefox
+### Firefox
 
 Type [about:config](about:config) in the Firefox address bar and search for `captivedetect.canonicalURL` and `network.connectivity-service`. Set the URL values to `https://connectivitycheck.sp-codes.de/generate204`, the domain values to `connectivitycheck.sp-codes.de`. That's it.