diff --git a/.github/workflows/hello.yml b/.github/workflows/hello.yml
index 54dec23..a8e074e 100644
--- a/.github/workflows/hello.yml
+++ b/.github/workflows/hello.yml
@@ -1,13 +1,276 @@
-name: CI
+name: Build
 
 on:
   push:
+    branches:
+      - master
   pull_request:
+    branches:
+      - master
+  schedule:
+    - cron: "9 16 * * 1"
 
 jobs:
-  hello:
-    runs-on: ubuntu-latest
+  build-test-repo:
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+      matrix:
+        cfg:
+          - lane: linux-gnu
+            runs-on: ubuntu-latest
+            python-version: "3.12"
+            cmargs: ""
+
+          - lane: linux-clang
+            runs-on: ubuntu-latest
+            python-version: "3.12"
+            cmargs: >
+              -D CMAKE_C_COMPILER=clang
+
+          - lane: linux-icpx
+            runs-on: ubuntu-latest
+            python-version: "3.12"
+            cmargs: >
+              -D CMAKE_C_COMPILER=icpx
+
+          - lane: linux-arm64-gnu
+            runs-on: ubuntu-24.04-arm
+            python-version: "3.12"
+            cmargs: ""
+
+          - lane: macos-silicon-clang
+            runs-on: macos-latest
+            python-version: "3.12"
+            cmargs: ""
+
+          - lane: windows-clang
+            runs-on: windows-latest
+            python-version: "3.12"
+            cmargs: >
+              -D CMAKE_C_COMPILER=clang-cl
+
+    name: "Repo - Python ${{ matrix.cfg.python-version }} - ${{ matrix.cfg.lane }}"
+    runs-on: ${{ matrix.cfg.runs-on }}
+    defaults:
+      run:
+        shell: bash -l {0}
+
     steps:
-      - name: Say hello
-        run: echo "Hello, GitHub Actions!"
+      - name: Checkout gau2grid
+        uses: actions/checkout@v5
+
+      - name: Prepare compiler environment, vcvarsall (W)
+        if: runner.os == 'Windows'
+        uses: ilammy/msvc-dev-cmd@v1
+        with:
+          arch: x64
+
+      - name: Write a Conda Env File
+        run: |
+          cat > export.yaml <<EOF
+          name: test
+          channels:
+            - conda-forge
+          dependencies:
+            - cmake
+            - ninja
+            - c-compiler
+            - python
+            - numpy
+            - pytest
+          EOF
+          if [[ "${{ matrix.cfg.lane }}" == "linux-clang" ]]; then
+            echo "  - clang_linux-64" >> export.yaml
+          fi
+          if [[ "${{ matrix.cfg.lane }}" == "linux-icpx" ]]; then
+            echo "  - dpcpp_linux-64" >> export.yaml
+          fi
+          cat export.yaml
+
+      - name: Create Conda Environment
+        uses: conda-incubator/setup-miniconda@v4
+        with:
+          python-version: ${{ matrix.cfg.python-version }}
+          activate-environment: test
+          channels: conda-forge
+          environment-file: export.yaml
+          show-channel-urls: true
+          auto-activate: false
+          add-pip-as-python-dependency: true
+          conda-remove-defaults: true
+
+      - name: Environment Information
+        run: |
+          conda info
+          conda list
+
+      - name: Build & Install gau2grid
+        run: |
+          cmake \
+            -S . \
+            -B build \
+            -G "Ninja" \
+            -D CMAKE_BUILD_TYPE=Release \
+            -D CMAKE_INSTALL_PREFIX="${{ github.workspace }}/installed" \
+            -D CMAKE_PREFIX_PATH="${CONDA_PREFIX};${CONDA_PREFIX}/Library" \
+            ${{ matrix.cfg.cmargs }}
+          cmake --build build --target install
+
+      - name: Testing find_package Consumption
+        run: |
+          mkdir consume_fp
+          cat > consume_fp/CMakeLists.txt <<EOF
+          cmake_minimum_required(VERSION 3.16)
+          project(gau2grid_consume LANGUAGES C)
+          find_package(gau2grid CONFIG REQUIRED)
+          add_executable(gau2grid_consume main.c)
+          target_link_libraries(gau2grid_consume PRIVATE gau2grid::gg)
+          EOF
+          cat > consume_fp/main.c <<EOF
+          #include <gau2grid/gau2grid.h>
+          int main(void) {
+              return (gg_max_L() < 0);
+          }
+          EOF
+          cmake \
+            -S consume_fp \
+            -B consume_fp/build \
+            -G "Ninja" \
+            -D CMAKE_BUILD_TYPE=Release \
+            -D CMAKE_PREFIX_PATH="${{ github.workspace }}/installed" \
+            ${{ matrix.cfg.cmargs }}
+          cmake --build consume_fp/build --target gau2grid_consume
+          if [[ "${{ runner.os }}" == "Linux" ]]; then
+            export LD_LIBRARY_PATH="${{ github.workspace }}/installed/lib:${LD_LIBRARY_PATH}"
+            ./consume_fp/build/gau2grid_consume
+          elif [[ "${{ runner.os }}" == "macOS" ]]; then
+            export DYLD_LIBRARY_PATH="${{ github.workspace }}/installed/lib:${DYLD_LIBRARY_PATH}"
+            ./consume_fp/build/gau2grid_consume
+          else
+            export PATH="${{ github.workspace }}/installed/bin:${PATH}"
+            ./consume_fp/build/gau2grid_consume.exe
+          fi
+
+  build-test-python:
+    timeout-minutes: 45
+    strategy:
+      fail-fast: false
+      matrix:
+        cfg:
+          - lane: linux-gnu
+            runs-on: ubuntu-latest
+          - lane: linux-arm64-gnu
+            runs-on: ubuntu-24.04-arm
+          - lane: macos-silicon-clang
+            runs-on: macos-latest
+        python-version: ["3.11", "3.12", "3.13"]
+
+    name: "Python - ${{ matrix.python-version }} - ${{ matrix.cfg.lane }}"
+    runs-on: ${{ matrix.cfg.runs-on }}
+    defaults:
+      run:
+        shell: bash -l {0}
+
+    steps:
+      - name: Checkout gau2grid
+        uses: actions/checkout@v5
+
+      - name: Write a Conda Env File
+        run: |
+          cat > export-py.yaml <<EOF
+          name: test-py
+          channels:
+            - conda-forge
+          dependencies:
+            - cmake
+            - ninja
+            - c-compiler
+            - python
+            - numpy
+            - pytest
+            - pip
+            - setuptools
+          EOF
+          cat export-py.yaml
+
+      - name: Create Conda Environment
+        uses: conda-incubator/setup-miniconda@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+          activate-environment: test-py
+          channels: conda-forge
+          environment-file: export-py.yaml
+          show-channel-urls: true
+          auto-activate: false
+          add-pip-as-python-dependency: true
+          conda-remove-defaults: true
+
+      - name: Environment Information
+        run: |
+          conda info
+          conda list
+
+      - name: Build and install Python package
+        run: |
+          python setup.py install
+
+      - name: Run Python tests
+        run: |
+          export GAU2GRID_FORCE_C_TEST=1
+          python -m pytest -rws -v --durations=10 --pyargs gau2grid
+
+  build-docs:
+    timeout-minutes: 20
+    needs: [build-test-repo]
+    strategy:
+      fail-fast: false
+      matrix:
+        cfg:
+          - label: Sphinx
+            python-version: "3.12"
+            runs-on: ubuntu-latest
+
+    name: "Docs - Python ${{ matrix.cfg.python-version }}"
+    runs-on: ${{ matrix.cfg.runs-on }}
+    defaults:
+      run:
+        shell: bash -l {0}
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Write a Conda Env File
+        run: |
+          cat > export-docs.yaml <<EOF
+          name: test-docs
+          channels:
+            - conda-forge
+          dependencies:
+            - python
+            - numpy
+            - sphinx
+            - sphinx_rtd_theme
+            - pip
+          EOF
+          cat export-docs.yaml
+
+      - name: Create Environment
+        uses: conda-incubator/setup-miniconda@v4
+        with:
+          activate-environment: test-docs
+          environment-file: export-docs.yaml
+          python-version: ${{ matrix.cfg.python-version }}
+          auto-activate: false
+          show-channel-urls: true
+          add-pip-as-python-dependency: true
+          channels: conda-forge
+
+      - name: Environment Information
+        run: |
+          conda info
+          conda list --show-channel-urls
 
+      - name: Build Documentation
+        run: |
+          make -C docs html SPHINXOPTS="-W --keep-going"