diff --git a/Dockerfile b/Dockerfile
index bdf752e..ae3f8a8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,31 +1,166 @@
-FROM archlinux:latest
+# ------------------------------------------------------------
+# Base image selector — overridden by Makefile
+# ------------------------------------------------------------
+ARG BASE_IMAGE=archlinux:latest
+FROM ${BASE_IMAGE}
 
-# 1) System basis + Nix
-RUN pacman -Syu --noconfirm \
-    && pacman -S --noconfirm --needed \
-        base-devel \
-        git \
-        nix \
-        rsync \
-    && pacman -Scc --noconfirm
+# ------------------------------------------------------------
+# System base + conditional package installation
+# ------------------------------------------------------------
+RUN set -e; \
+    if [ -f /etc/os-release ]; then . /etc/os-release; else echo "No /etc/os-release found" && exit 1; fi; \
+    echo "Detected base image: ${ID:-unknown} (like: ${ID_LIKE:-})"; \
+    \
+    # --------------------------------------------------------
+    # Archlinux: Nix via pacman
+    # --------------------------------------------------------
+    if [ "$ID" = "arch" ]; then \
+        pacman -Syu --noconfirm && \
+        pacman -S --noconfirm --needed \
+            base-devel \
+            git \
+            nix \
+            rsync && \
+        pacman -Scc --noconfirm; \
+    \
+    # --------------------------------------------------------
+    # Debian: Nix installer (single-user, root, no build-users-group)
+    # --------------------------------------------------------
+    elif [ "$ID" = "debian" ]; then \
+        apt-get update && \
+        DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+            ca-certificates \
+            curl \
+            git \
+            python3 \
+            python3-venv \
+            rsync \
+            bash \
+            xz-utils && \
+        rm -rf /var/lib/apt/lists/* && \
+        echo "Preparing /nix + /etc/nix/nix.conf on Debian..." && \
+        mkdir -p /nix && chmod 0755 /nix && chown root:root /nix && \
+        mkdir -p /etc/nix && printf 'build-users-group =\n' > /etc/nix/nix.conf && \
+        echo "Downloading Nix installer on Debian..." && \
+        curl -L https://nixos.org/nix/install -o /tmp/nix-install && \
+        echo "Installing Nix on Debian (single-user, as root, no build-users-group)..." && \
+        HOME=/root NIX_INSTALLER_NO_MODIFY_PROFILE=1 sh /tmp/nix-install --no-daemon && \
+        rm -f /tmp/nix-install; \
+    \
+    # --------------------------------------------------------
+    # Ubuntu: Nix installer (single-user, root, no build-users-group)
+    # --------------------------------------------------------
+    elif [ "$ID" = "ubuntu" ]; then \
+        apt-get update && \
+        DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+            ca-certificates \
+            curl \
+            git \
+            tzdata \
+            lsb-release \
+            python3 \
+            python3-venv \
+            rsync \
+            bash \
+            xz-utils && \
+        rm -rf /var/lib/apt/lists/* && \
+        echo "Preparing /nix + /etc/nix/nix.conf on Ubuntu..." && \
+        mkdir -p /nix && chmod 0755 /nix && chown root:root /nix && \
+        mkdir -p /etc/nix && printf 'build-users-group =\n' > /etc/nix/nix.conf && \
+        echo "Downloading Nix installer on Ubuntu..." && \
+        curl -L https://nixos.org/nix/install -o /tmp/nix-install && \
+        echo "Installing Nix on Ubuntu (single-user, as root, no build-users-group)..." && \
+        HOME=/root NIX_INSTALLER_NO_MODIFY_PROFILE=1 sh /tmp/nix-install --no-daemon && \
+        rm -f /tmp/nix-install; \
+    \
+    # --------------------------------------------------------
+    # Fedora: Nix installer (single-user, root, no build-users-group)
+    # --------------------------------------------------------
+    elif [ "$ID" = "fedora" ]; then \
+        dnf -y update && \
+        dnf -y install \
+            ca-certificates \
+            curl \
+            git \
+            python3 \
+            rsync \
+            bash \
+            xz && \
+        dnf clean all && \
+        echo "Preparing /nix + /etc/nix/nix.conf on Fedora..." && \
+        mkdir -p /nix && chmod 0755 /nix && chown root:root /nix && \
+        mkdir -p /etc/nix && printf 'build-users-group =\n' > /etc/nix/nix.conf && \
+        echo "Downloading Nix installer on Fedora..." && \
+        curl -L https://nixos.org/nix/install -o /tmp/nix-install && \
+        echo "Installing Nix on Fedora (single-user, as root, no build-users-group)..." && \
+        HOME=/root NIX_INSTALLER_NO_MODIFY_PROFILE=1 sh /tmp/nix-install --no-daemon && \
+        rm -f /tmp/nix-install; \
+    \
+    # --------------------------------------------------------
+    # CentOS Stream: Nix installer (single-user, root, no build-users-group)
+    # --------------------------------------------------------
+    elif [ "$ID" = "centos" ]; then \
+        dnf -y update && \
+        dnf -y install \
+            ca-certificates \
+            curl-minimal \
+            git \
+            python3 \
+            rsync \
+            bash \
+            xz && \
+        dnf clean all && \
+        echo "Preparing /nix + /etc/nix/nix.conf on CentOS..." && \
+        mkdir -p /nix && chmod 0755 /nix && chown root:root /nix && \
+        mkdir -p /etc/nix && printf 'build-users-group =\n' > /etc/nix/nix.conf && \
+        echo "Downloading Nix installer on CentOS..." && \
+        curl -L https://nixos.org/nix/install -o /tmp/nix-install && \
+        echo "Installing Nix on CentOS (single-user, as root, no build-users-group)..." && \
+        HOME=/root NIX_INSTALLER_NO_MODIFY_PROFILE=1 sh /tmp/nix-install --no-daemon && \
+        rm -f /tmp/nix-install; \
+    \
+    # --------------------------------------------------------
+    # Unknown distro
+    # --------------------------------------------------------
+    else \
+        echo "Unsupported base image: ${ID}" && exit 1; \
+    fi
 
+# Nix CLI behavior (used later in tests)
 ENV NIX_CONFIG="experimental-features = nix-command flakes"
+ENV PATH="/root/.nix-profile/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 
-# 2) Unprivileged user for building Arch packages
+# ------------------------------------------------------------
+# Create unprivileged build user (used on Arch for makepkg)
+# ------------------------------------------------------------
 RUN useradd -m builder
 
-# 3) Build-Stage (optional): einmal aus /build bauen, wenn du magst
+# ------------------------------------------------------------
+# Build stage — only active on Arch
+# ------------------------------------------------------------
 WORKDIR /build
 COPY . .
-RUN chown -R builder:builder /build \
-    && su builder -c "cd /build && rm -f package-manager-*.pkg.tar.* && makepkg -sf --noconfirm --clean" \
-    && pacman -U --noconfirm package-manager-*.pkg.tar.* \
-    && rm -rf /build
 
-# 4) Runtime-Workingdir für das gemountete Repo
+RUN set -e; \
+    if [ -f /etc/os-release ]; then . /etc/os-release; fi; \
+    if [ "$ID" = "arch" ]; then \
+        echo "Running Arch build stage (makepkg)..."; \
+        chown -R builder:builder /build && \
+        su builder -c "cd /build && rm -f package-manager-*.pkg.tar.* && makepkg -sf --noconfirm --clean"; \
+        pacman -U --noconfirm package-manager-*.pkg.tar.*; \
+    else \
+        echo "Non-Arch base detected — skipping Arch package build."; \
+    fi; \
+    rm -rf /build
+
+# ------------------------------------------------------------
+# Runtime working directory for the mounted repository
+# ------------------------------------------------------------
 WORKDIR /src
 
-# 5) Entry-Script für „always build from /src“
+# ------------------------------------------------------------
+# Development entry script
+# ------------------------------------------------------------
 COPY scripts/docker-entry-dev.sh /usr/local/bin/docker-entry-dev.sh
 RUN chmod +x /usr/local/bin/docker-entry-dev.sh
 
diff --git a/Makefile b/Makefile
index bcbf3d5..fe4fc1c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,31 @@
-.PHONY: install setup uninstall aur_builder_setup test
+.PHONY: install setup uninstall aur_builder_setup \
+        test build build-no-cache
 
+# ------------------------------------------------------------
 # Local Nix cache directories in the repo
+# ------------------------------------------------------------
 NIX_STORE_VOLUME := pkgmgr_nix_store
 NIX_CACHE_VOLUME := pkgmgr_nix_cache
 
+# ------------------------------------------------------------
+# Distro list and base images
+# ------------------------------------------------------------
+DISTROS := arch #debian ubuntu fedora centos
+
+BASE_IMAGE_arch   := archlinux:latest
+BASE_IMAGE_debian := debian:stable-slim
+BASE_IMAGE_ubuntu := ubuntu:latest
+BASE_IMAGE_fedora := fedora:latest
+BASE_IMAGE_centos := quay.io/centos/centos:stream9
+
+# Helper to echo which image is used for which distro (purely informational)
+define echo_build_info
+	@echo "Building image for distro '$(1)' with base image '$(2)'..."
+endef
+
+# ------------------------------------------------------------
+# PKGMGR setup (wrapper)
+# ------------------------------------------------------------
 setup: install
 	@echo "Running pkgmgr setup via main.py..."
 	@if [ -x "$$HOME/.venvs/pkgmgr/bin/python" ]; then \
@@ -14,44 +36,129 @@ setup: install
 		python3 main.py install; \
 	fi
 
-
+# ------------------------------------------------------------
+# Docker build targets: build all images
+# ------------------------------------------------------------
 build-no-cache:
-	@echo "Building test image 'package-manager-test' with no cache..."
-	docker build --no-cache -t package-manager-test .
+	@for distro in $(DISTROS); do \
+		case "$$distro" in \
+			arch)   base_image="$(BASE_IMAGE_arch)" ;; \
+			debian) base_image="$(BASE_IMAGE_debian)" ;; \
+			ubuntu) base_image="$(BASE_IMAGE_ubuntu)" ;; \
+			fedora) base_image="$(BASE_IMAGE_fedora)" ;; \
+			centos) base_image="$(BASE_IMAGE_centos)" ;; \
+			*)      echo "Unknown distro '$$distro'" >&2; exit 1 ;; \
+		esac; \
+		echo "Building test image 'package-manager-test-$$distro' with no cache (BASE_IMAGE=$$base_image)..."; \
+		docker build --no-cache \
+			--build-arg BASE_IMAGE="$$base_image" \
+			-t "package-manager-test-$$distro" . || exit $$?; \
+	done
 
 build:
-	@echo "Building test image 'package-manager-test'..."
-	docker build -t package-manager-test .
-
+	@for distro in $(DISTROS); do \
+		case "$$distro" in \
+			arch)   base_image="$(BASE_IMAGE_arch)" ;; \
+			debian) base_image="$(BASE_IMAGE_debian)" ;; \
+			ubuntu) base_image="$(BASE_IMAGE_ubuntu)" ;; \
+			fedora) base_image="$(BASE_IMAGE_fedora)" ;; \
+			centos) base_image="$(BASE_IMAGE_centos)" ;; \
+			*)      echo "Unknown distro '$$distro'" >&2; exit 1 ;; \
+		esac; \
+		echo "Building test image 'package-manager-test-$$distro' (BASE_IMAGE=$$base_image)..."; \
+		docker build \
+			--build-arg BASE_IMAGE="$$base_image" \
+			-t "package-manager-test-$$distro" . || exit $$?; \
+	done
 
+# ------------------------------------------------------------
+# Test target: run tests in all three images
+# ------------------------------------------------------------
 test: build
 	@echo "Ensuring Docker Nix volumes exist (auto-created if missing)..."
-	@echo "Running tests inside Nix devShell with cached store..."
-	docker run --rm \
-		-v "$$(pwd):/src" \
-		-v "$(NIX_STORE_VOLUME):/nix" \
-		-v "$(NIX_CACHE_VOLUME):/root/.cache/nix" \
-		--workdir /src \
-		--entrypoint bash \
-		package-manager-test \
-		-c '\
-			set -e; \
-			echo "Remove existing Arch package-manager (if any)..."; \
-			pacman -Rns --noconfirm package-manager || true; \
-			echo "Rebuild Arch package from /src..."; \
-			rm -f /src/package-manager-*.pkg.tar.* || true; \
-			chown -R builder:builder /src; \
-			su builder -c "cd /src && makepkg -sf --noconfirm --clean"; \
-			pacman -U --noconfirm /src/package-manager-*.pkg.tar.*; \
-			echo "Run tests inside Nix devShell..."; \
-			git config --global --add safe.directory /src && \
-			cd /src && \
-			nix develop .#default --no-write-lock-file -c \
-				python3 -m unittest discover \
-					-s /src/tests \
-					-p "test_*.py" \
-		'
+	@echo "Running tests inside Nix devShell with cached store for all distros: $(DISTROS)"
 
+	@for distro in $(DISTROS); do \
+		echo "============================================================"; \
+		echo ">>> Running tests in container for distro: $$distro"; \
+		echo "============================================================"; \
+		docker run --rm \
+			-v "$$(pwd):/src" \
+			-v "$(NIX_STORE_VOLUME):/nix" \
+			-v "$(NIX_CACHE_VOLUME):/root/.cache/nix" \
+			--workdir /src \
+			--entrypoint bash \
+			"package-manager-test-$$distro" \
+			-c '\
+				set -e; \
+				if [ -f /etc/os-release ]; then . /etc/os-release; fi; \
+				echo "Detected container distro: $${ID:-unknown} (like: $${ID_LIKE:-})"; \
+				\
+				# Arch-only: rebuild Arch package inside the container \
+				if [ "$${ID}" = "arch" ]; then \
+					echo "Remove existing Arch package-manager (if any)..."; \
+					pacman -Rns --noconfirm package-manager || true; \
+					echo "Rebuild Arch package from /src..."; \
+					rm -f /src/package-manager-*.pkg.tar.* || true; \
+					chown -R builder:builder /src; \
+					su builder -c "cd /src && makepkg -sf --noconfirm --clean"; \
+					pacman -U --noconfirm /src/package-manager-*.pkg.tar.*; \
+				else \
+					echo "Non-Arch distro – skipping Arch package rebuild."; \
+				fi; \
+				\
+				echo "Preparing Nix environment..."; \
+				# Try to source typical Nix profile scripts (if they exist) \
+				if [ -f "/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh" ]; then \
+					. "/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh"; \
+				fi; \
+				if [ -f "$$HOME/.nix-profile/etc/profile.d/nix.sh" ]; then \
+					. "$$HOME/.nix-profile/etc/profile.d/nix.sh"; \
+				fi; \
+				# Hard-extend PATH for common Nix locations \
+				PATH="/nix/var/nix/profiles/default/bin:$$HOME/.nix-profile/bin:$$PATH"; \
+				export PATH; \
+				echo "PATH is now:"; \
+				echo "$$PATH"; \
+				\
+				# Determine which Nix binary to use \
+				NIX_CMD=""; \
+				if command -v nix >/dev/null 2>&1; then \
+					echo "Found nix on PATH:"; \
+					command -v nix; \
+					NIX_CMD="nix"; \
+				else \
+					echo "nix not found on PATH, scanning /nix/store for a nix binary..."; \
+					for path in /nix/store/*-nix-*/bin/nix; do \
+						if [ -x "$$path" ]; then \
+							echo "Found nix binary at $$path"; \
+							NIX_CMD="$$path"; \
+							break; \
+						fi; \
+					done; \
+				fi; \
+				\
+				if [ -z "$$NIX_CMD" ]; then \
+					echo "ERROR: nix binary not found anywhere – cannot run devShell"; \
+					exit 1; \
+				fi; \
+				\
+				echo "Using Nix command: $$NIX_CMD"; \
+				echo "Run tests inside Nix devShell..."; \
+				git config --global --add safe.directory /src; \
+				cd /src; \
+				"$$NIX_CMD" develop .#default --no-write-lock-file -c \
+					python3 -m unittest discover \
+						-s /src/tests \
+						-p "test_*.py"; \
+			' || exit $$?; \
+	done
+
+
+
+# ------------------------------------------------------------
+# Installer for host systems (your original logic)
+# ------------------------------------------------------------
 install:
 	@if [ -n "$$IN_NIX_SHELL" ]; then \
 		echo "Nix shell detected (IN_NIX_SHELL=1). Skipping venv/pip install – handled by Nix flake."; \
@@ -93,18 +200,17 @@ install:
 		echo "Installation complete. Please restart your shell (or 'exec bash' or 'exec zsh') for the changes to take effect."; \
 	fi
 
-# Only runs on Arch/Manjaro
+# ------------------------------------------------------------
+# AUR builder setup — only on Arch/Manjaro
+# ------------------------------------------------------------
 aur_builder_setup:
 	@echo "Setting up aur_builder and yay (Arch/Manjaro)..."
 	@sudo pacman -Syu --noconfirm
 	@sudo pacman -S --needed --noconfirm base-devel git sudo
-	@# group & user
 	@if ! getent group aur_builder >/dev/null; then sudo groupadd -r aur_builder; fi
 	@if ! id -u aur_builder >/dev/null 2>&1; then sudo useradd -m -r -g aur_builder -s /bin/bash aur_builder; fi
-	@# sudoers rule for pacman
 	@echo '%aur_builder ALL=(ALL) NOPASSWD: /usr/bin/pacman' | sudo tee /etc/sudoers.d/aur_builder >/dev/null
 	@sudo chmod 0440 /etc/sudoers.d/aur_builder
-	@# yay install (if missing)
 	@if ! sudo -u aur_builder bash -lc 'command -v yay >/dev/null'; then \
 		sudo -u aur_builder bash -lc 'cd ~ && rm -rf yay && git clone https://aur.archlinux.org/yay.git && cd yay && makepkg -si --noconfirm'; \
 	else \
@@ -112,6 +218,9 @@ aur_builder_setup:
 	fi
 	@echo "aur_builder/yay setup complete."
 
+# ------------------------------------------------------------
+# Uninstall target
+# ------------------------------------------------------------
 uninstall:
 	@echo "Removing global user virtual environment if it exists..."
 	@rm -rf "$$HOME/.venvs/pkgmgr"