diff --git a/.ci/docker/rockylinux.Dockerfile b/.ci/docker/rockylinux.Dockerfile
deleted file mode 100644
index 17823a3..0000000
--- a/.ci/docker/rockylinux.Dockerfile
+++ /dev/null
@@ -1,35 +0,0 @@
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-FROM rockylinux:9
-
-# Enable EPEL.
-RUN dnf update -y
-RUN dnf install -y 'dnf-command(config-manager)'
-RUN dnf config-manager --set-enabled crb -y
-RUN dnf install epel-release -y
-
-# Install dependencies.
-RUN dnf install -y \
-        clang \
-        g++ \
-        ninja-build \
-        cmake \
-        git
-RUN dnf clean all
-
-# Copy code.
-WORKDIR /workarea
-COPY ./ ./
-
-# Set build arguments.
-ARG cc=gcc
-ARG cxx=g++
-ARG cmake_args=
-
-# Build.
-ENV CC="$cc" CXX="$cxx" CMAKE_GENERATOR="Ninja" CMAKE_EXPORT_COMPILE_COMMANDS=on
-RUN cmake -B build -S . "$cmake_args"
-RUN cmake --build build --verbose
-RUN cmake --install build --prefix /opt/beman.dump
-RUN find /opt/beman.dump -type f
-
diff --git a/.ci/docker/ubuntu.Dockerfile b/.ci/docker/ubuntu.Dockerfile
deleted file mode 100644
index cfb3c81..0000000
--- a/.ci/docker/ubuntu.Dockerfile
+++ /dev/null
@@ -1,34 +0,0 @@
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-# Using a non-LTS Ubuntu, just until CMake 3.23 is available on Ubuntu 24.04.
-FROM ubuntu:23.10
-
-# Install dependencies,
-RUN apt-get update
-RUN apt-get install -y \
-        clang \
-        clang-tidy \
-        g++ \
-        ninja-build \
-        cmake \
-        git
-RUN apt-get clean
-
-WORKDIR /workarea
-COPY ./ ./
-
-# Set build arguments.
-ARG cc=gcc
-ARG cxx=g++
-ARG cmake_args=
-
-# Workaround Ubuntu broken ASan
-RUN sysctl vm.mmap_rnd_bits=28
-
-# Build.
-ENV CC="$cc" CXX="$cxx" CMAKE_GENERATOR="Ninja" CMAKE_EXPORT_COMPILE_COMMANDS=on
-RUN ls -lR src
-RUN cmake -B build -S . "$cmake_args"
-RUN cmake --build build --verbose
-RUN cmake --install build --prefix /opt/beman.example
-RUN find /opt/beman.example -type f
diff --git a/.github/workflows/ci_tests.yml b/.github/workflows/ci_tests.yml
index 0f3c8cc..a32156f 100644
--- a/.github/workflows/ci_tests.yml
+++ b/.github/workflows/ci_tests.yml
@@ -21,50 +21,28 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
-        cfg:
-          - { id: ubuntu-gcc-static-cxx23, platform: ubuntu, cc: gcc, cpp: g++, cmake_args: "-DCMAKE_CXX_STANDARD=23 -DCMAKE_CXX_STANDARD_REQUIRED=on"}
-          - { id: ubuntu-gcc-static-cxx26, platform: ubuntu, cc: gcc, cpp: g++, cmake_args: "-DCMAKE_CXX_STANDARD=26 -DCMAKE_CXX_STANDARD_REQUIRED=on"}
-          - { id: ubuntu-clang-static-cxx23, platform: ubuntu, cc: clang, cpp: clang++, cmake_args: "-DCMAKE_CXX_STANDARD=23 -DCMAKE_CXX_STANDARD_REQUIRED=on"}
-          - { id: ubuntu-clang-static-cxx26, platform: ubuntu, cc: clang, cpp: clang++, cmake_args: "-DCMAKE_CXX_STANDARD=26 -DCMAKE_CXX_STANDARD_REQUIRED=on"}
+        image:
+          - "gcc:14"
+        build_type: [Debug, Release]
+
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/foonathan/${{matrix.image}}
 
     steps:
-      - uses: actions/checkout@v2
-      # GitHub runners have updated the Ubuntu Linux Kernel to use strong ASLR,
-      # but LLVM is not configured for this change, and thus the address
-      # sanitizer breaks.
-      #
-      # The next image is supposed to fix this, so if the Ubuntu image has been
-      # updated, this work around is no longer required.
-      - name: get runner image version
-        id: runner-image-version
-        run: |
-          echo "image-version=$(echo $ImageVersion)" >> "$GITHUB_OUTPUT"
-        working-directory: .
-      - name: modify number of bits to use for ASLR entropy
-        if: ${{ steps.runner-image-version.outputs.ImageVersion }} == '20240310.1.0'
-        run: |
-          sudo sysctl -a | grep vm.mmap.rnd
-          sudo sysctl -w vm.mmap_rnd_bits=28
-        working-directory: .
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-      - name: Build and push
-        uses: docker/build-push-action@v5
-        with:
-          context: .
-          push: false
-          load: true
-          tags: ${{ matrix.cfg.id }}
-          file: .ci/docker/${{ matrix.cfg.platform }}.Dockerfile
-          build-args: |
-            cc=${{ matrix.cfg.cc }}
-            cxx=${{ matrix.cfg.cpp }}
-            cmake_args=${{ matrix.cfg.cmake_args }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-      - name: Run tests
-        run: |
-          docker run ${{ matrix.cfg.id }} ctest --test-dir build
+    - uses: actions/checkout@v4
+    - name: Create Build Environment
+      run: cmake -E make_directory build
+
+    - name: Configure
+      working-directory: build/
+      run: cmake -GNinja $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DCMAKE_CXX_FLAGS="-Werror -Wall -Wextra"
+    - name: Build
+      working-directory: build/
+      run: cmake --build .
+    - name: Test
+      working-directory: build/
+      run: ctest --output-on-failure