diff --git a/tools/watch.sh b/tools/watch.sh
index 5e8defa49c..8c63d44b59 100644
--- a/tools/watch.sh
+++ b/tools/watch.sh
@@ -1,8 +1,13 @@
 #!/bin/bash
 set -euo pipefail
 
-make --no-print-directory watch-frontend &
-make --no-print-directory watch-backend &
+make --no-print-directory watch-frontend | tee >(
+  awk -v pattern="webpack" '
+    $0 ~ pattern {
+      system("make --no-print-directory watch-backend &")
+    }
+  '
+) &
 
 trap 'kill $(jobs -p)' EXIT
 wait
diff --git a/webpack.config.js b/webpack.config.js
index 8f9949d7b1..90f8daea32 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -157,6 +157,7 @@ export default {
         minify: true,
         css: true,
         legalComments: 'none',
+        exclude: [new RegExp(`css\\/(${Object.keys(themes).join('|')})\\.css$`)],
       }),
     ],
     splitChunks: {