diff --git a/consent-tester/Dockerfile b/consent-tester/Dockerfile
index 5eda3767..d0b466c7 100644
--- a/consent-tester/Dockerfile
+++ b/consent-tester/Dockerfile
@@ -23,6 +23,12 @@ RUN useradd --create-home appuser
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
+# OS-Libs fuer ALLE drei Engines (Chromium/Firefox/WebKit) — offizieller
+# Playwright-Weg statt der manuellen Liste oben, die fuer Firefox/WebKit
+# unvollstaendig war: Engines scheiterten sonst mit "Host system is missing
+# dependencies to run browsers" (nur Chromium lief). Als root (apt).
+RUN playwright install-deps chromium firefox webkit
+
 # Install Playwright browsers AS appuser (so they land in /home/appuser/.cache/)
 # Stage 1: chromium + firefox + webkit (Mobile-Safari = WebKit + devices preset)
 USER appuser