diff --git a/cmake/toolchain-aarch64-linux-gnu.cmake b/cmake/toolchain-aarch64-linux-gnu.cmake
new file mode 100644
index 0000000..7f9d74c
--- /dev/null
+++ b/cmake/toolchain-aarch64-linux-gnu.cmake
@@ -0,0 +1,20 @@
+# ============================================================================
+# CMake toolchain file for cross-compiling to Linux ARM64 (aarch64)
+# ============================================================================
+# Usage:
+#   cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-aarch64-linux-gnu.cmake
+# ============================================================================
+
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR aarch64)
+
+# Cross-compiler (Ubuntu: apt install g++-aarch64-linux-gnu)
+set(CMAKE_C_COMPILER   aarch64-linux-gnu-gcc)
+set(CMAKE_CXX_COMPILER aarch64-linux-gnu-g++)
+
+# Search paths: only cross-root for libraries/headers, host for programs
+set(CMAKE_FIND_ROOT_PATH /usr/aarch64-linux-gnu)
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)