diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4aa22bad..6b5fccf8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,36 +10,45 @@ env:
   CARGO_TERM_COLOR: always
   RUST_BACKTRACE: 1
 
+# ── What this file may assume about where it runs ────────────────────────────
+#
+# It runs on ONE self-hosted runner: `rpi5-runner`, aarch64, advertising
+# ["ubuntu-latest", "ubuntu-24.04", "ubuntu-22.04"]. Nothing else exists.
+#
+# This file was written for GitHub's hosted fleet — three operating systems and
+# x86_64 throughout — and had never once gone green here: 23 runs cancelled, 2
+# waiting, zero successes. Two separate reasons, and both are configuration
+# describing a world that is not this one:
+#
+#   * `windows-latest` / `macos-latest` match no runner label, so those jobs sit
+#     in WAITING for ever. The run therefore never reaches a terminal state, and
+#     a pull request's checks never resolve either way — not red, just never
+#     finished. That is worse than a failure: a red check tells you something.
+#   * `--target x86_64-unknown-linux-gnu` on an aarch64 host makes every build a
+#     cross-compile, and `wayland-sys`'s build script dies on it —
+#     "pkg-config has not been configured to support cross-compilation".
+#
+# So: one job, on the machine that exists, building for the machine that exists.
+# If a second architecture is ever wanted here it needs a second RUNNER, not a
+# second matrix row.
+
 jobs:
-  # ── Native builds: Windows, macOS, Linux ────────────────────────────────────
+  # ── Native build, on the one runner there is ────────────────────────────────
   native:
-    name: Native — ${{ matrix.os }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - os: ubuntu-latest
-            target: x86_64-unknown-linux-gnu
-          - os: windows-latest
-            target: x86_64-pc-windows-msvc
-          - os: macos-latest
-            target: aarch64-apple-darwin
+    name: Native — linux
+    runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v4
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@stable
-        with:
-          targets: ${{ matrix.target }}
 
       - name: Cache Cargo registry and build
         uses: Swatinem/rust-cache@v2
 
       # Linux: install Bevy's system dependencies (X11, Wayland, audio)
       - name: Install Linux system dependencies
-        if: matrix.os == 'ubuntu-latest'
         run: |
           sudo apt-get update
           sudo apt-get install -y \
@@ -52,16 +61,16 @@ jobs:
             pkg-config
 
       - name: Check (fast compile check)
-        run: cargo check --workspace --target ${{ matrix.target }}
+        run: cargo check --workspace
 
       - name: Build (debug)
-        run: cargo build --workspace --target ${{ matrix.target }}
+        run: cargo build --workspace
 
       - name: Run tests
-        run: cargo test --workspace --target ${{ matrix.target }}
+        run: cargo test --workspace
 
       - name: Clippy
-        run: cargo clippy --workspace --target ${{ matrix.target }} -- -D warnings
+        run: cargo clippy --workspace -- -D warnings
 
   # ── WASM / Web build ─────────────────────────────────────────────────────────
   wasm: