diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4baac31..efc7f6f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -259,8 +259,8 @@ jobs:
     needs: posix
     runs-on: ubuntu-latest
     steps:
-    - name: Coveralls Finished
-      uses: coverallsapp/github-action@master
-      with:
-        github-token: ${{ secrets.github_token }}
-        parallel-finished: true
+      - name: Coveralls Finished
+        uses: coverallsapp/github-action@master
+        with:
+          github-token: ${{ secrets.github_token }}
+          parallel-finished: true
diff --git a/.gitignore b/.gitignore
index dbcd323..2a06130 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,5 @@ doc/html
 build*
 .cache
 .vscode
+compile_commands.json
+GNUmakefile
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2275d3b..6bdabf0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,47 +1,135 @@
-# Generated by `boostdep --cmake type_index`
+# -----------------------------------------------------------------------------
+# Boost.type_index CMake
+# Handles: no modules, modules, modules + import std;
+# -----------------------------------------------------------------------------
 # Copyright 2020, 2021 Peter Dimov
 # Copyright 2026 Fedor Osetrov
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
 
-cmake_minimum_required(VERSION 3.5...4.20)
+cmake_minimum_required(VERSION 3.28...4.4)
 
 project(boost_type_index VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
-if (BOOST_USE_MODULES)
+if(PROJECT_IS_TOP_LEVEL)
+    set(BUILD_TESTING ON)
+    enable_testing()
+    find_package(Threads)
+    find_package(Boost 1.91.0 CONFIG REQUIRED)
+endif()
+
+# -----------------------------------------------------------------------------
+# User option: enable C++ modules
+# -----------------------------------------------------------------------------
+option(BOOST_USE_MODULES "Build Boost using C++ modules" OFF)
+
+# -----------------------------------------------------------------------------
+# Determine target type and sources
+# -----------------------------------------------------------------------------
+if(BOOST_USE_MODULES)
+
+    # Ensure CMAKE_CXX_STANDARD is set for module detection
+    if(NOT DEFINED CMAKE_CXX_STANDARD)
+        set(CMAKE_CXX_STANDARD 20)
+    endif()
+
     add_library(boost_type_index)
-    target_sources(boost_type_index
-      PUBLIC
-        FILE_SET CXX_MODULES
-        BASE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}"
-        FILES "${CMAKE_CURRENT_SOURCE_DIR}/modules/boost_type_index.cppm"
+    target_sources(
+        boost_type_index
+        PUBLIC
+            FILE_SET modules_public
+                TYPE CXX_MODULES
+                FILES modules/boost_type_index.cppm
     )
 
-    target_compile_features(boost_type_index PUBLIC cxx_std_20)
+    # Require C++20 for modules
+    target_compile_features(boost_type_index PUBLIC cxx_std_${CMAKE_CXX_STANDARD})
+    # Define macro indicating modules usage
     target_compile_definitions(boost_type_index PUBLIC BOOST_USE_MODULES)
-    if ((CMAKE_CXX_STANDARD IN_LIST CMAKE_CXX_COMPILER_IMPORT_STD) AND CMAKE_CXX_MODULE_STD)
-        target_compile_features(boost_type_index PRIVATE cxx_std_23)
-        target_compile_definitions(boost_type_index PRIVATE BOOST_TYPE_INDEX_USE_STD_MODULE)
-        message(STATUS "Using `import std;`")
+
+    # Check if import std; is available for the current standard
+    if(${CMAKE_CXX_STANDARD} IN_LIST CMAKE_CXX_COMPILER_IMPORT_STD)
+        target_compile_definitions(boost_type_index PUBLIC BOOST_TYPE_INDEX_USE_STD_MODULE)
+        set_property(TARGET boost_type_index PROPERTY CXX_MODULE_STD ON)
+        message(STATUS "Boost.type_index: Using `import std;`")
     else()
-        message(STATUS "`import std;` is not available")
+        message(WARNING "Boost.type_index: `import std;` is not available for C++${CMAKE_CXX_STANDARD}")
     endif()
+
     set(__scope PUBLIC)
+
 else()
+
+    # Verify interface headers only at top level
+    if(PROJECT_IS_TOP_LEVEL)
+        set(CMAKE_VERIFY_INTERFACE_HEADER_SETS ON)
+    endif()
+
+    # Modules disabled -> INTERFACE library
     add_library(boost_type_index INTERFACE)
+
+    # If modules are disabled, require C++17 for headers
+    target_compile_features(boost_type_index INTERFACE cxx_std_17)
+
     set(__scope INTERFACE)
+
 endif()
 
-target_include_directories(boost_type_index ${__scope} include)
-add_library(Boost::type_index ALIAS boost_type_index)
+# -----------------------------------------------------------------------------
+# Include headers
+# -----------------------------------------------------------------------------
+# Note: usable starting with cmake v3.23
+if(NOT CMAKE_VERSION VERSION_LESS 3.23)
+    target_sources(
+        boost_type_index
+        PUBLIC
+            FILE_SET headers_public
+                TYPE HEADERS
+                BASE_DIRS include
+                FILES
+                    include/boost/type_index.hpp
+                    include/boost/type_index/runtime_cast.hpp
+                    include/boost/type_index/stl_type_index.hpp
+                    include/boost/type_index/detail/compile_time_type_info.hpp
+                    include/boost/type_index/detail/stl_register_class.hpp
+                    include/boost/type_index/detail/config.hpp
+                    include/boost/type_index/detail/ctti_register_class.hpp
+                    include/boost/type_index/ctti_type_index.hpp
+                    include/boost/type_index/runtime_cast/std_shared_ptr_cast.hpp
+                    include/boost/type_index/runtime_cast/detail/runtime_cast_impl.hpp
+                    include/boost/type_index/runtime_cast/register_runtime_class.hpp
+                    include/boost/type_index/runtime_cast/pointer_cast.hpp
+                    include/boost/type_index/runtime_cast/reference_cast.hpp
+                    include/boost/type_index/runtime_cast/boost_shared_ptr_cast.hpp
+                    include/boost/type_index/type_index_facade.hpp
+    )
+else()
+    target_include_directories(boost_type_index ${__scope} include)
+endif()
+
+# -----------------------------------------------------------------------------
+# Link dependencies
+# -----------------------------------------------------------------------------
+if(PROJECT_IS_TOP_LEVEL)
+    target_link_libraries(boost_type_index ${__scope} Boost::headers)
+else()
+    target_link_libraries(boost_type_index
+        ${__scope}
+        Boost::config
+        Boost::container_hash
+        Boost::core
+        Boost::smart_ptr
+        Boost::throw_exception
+        Boost::unordered
+    )
+endif()
 
-target_link_libraries(boost_type_index
-  ${__scope}
-    Boost::config
-    Boost::container_hash
-    Boost::throw_exception
-)
+# Alias for convenient import
+add_library(Boost::type_index ALIAS boost_type_index)
 
+# -----------------------------------------------------------------------------
+# Testing
+# -----------------------------------------------------------------------------
 if(BUILD_TESTING)
-  add_subdirectory(test)
+    add_subdirectory(test)
 endif()
diff --git a/modules/boost_type_index.cppm b/modules/boost_type_index.cppm
index c40a43a..e16f081 100644
--- a/modules/boost_type_index.cppm
+++ b/modules/boost_type_index.cppm
@@ -9,8 +9,6 @@
 module;
 
 #include <version>
-#include <cstddef>
-#include <cstdint>
 
 #if __has_include(<cxxabi.h>)
 #  include <cxxabi.h>
@@ -22,6 +20,8 @@ module;
 #include <boost/throw_exception.hpp>
 
 #ifndef BOOST_TYPE_INDEX_USE_STD_MODULE
+#include <cstdint>
+#include <cstddef>
 #include <cstring>
 #include <cstdlib>
 #include <iosfwd>
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 29cde66..eeea37c 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -25,7 +25,7 @@ target_link_libraries(boost_type_index_test_lib_anonymous_rtti PRIVATE Boost::ty
 
 function(boost_type_index_test name sources)
     add_executable(${name} "${sources}")
-    target_link_libraries(${name} PRIVATE Boost::core ${ARGN})
+    target_link_libraries(${name} PRIVATE Boost::type_index ${ARGN})
     add_test(NAME ${name} COMMAND ${name})
     add_dependencies(tests ${name})
 endfunction()
@@ -49,16 +49,13 @@ function(boost_type_index_add_target target)
   target_include_directories(${target} ${__scope} ../include)
   target_link_libraries(${target}
     ${__scope}
-        Boost::config
-        Boost::container_hash
-        Boost::throw_exception
   )
 endfunction()
 
 boost_type_index_test(type_index_test type_index_test.cpp Boost::type_index)
 boost_type_index_test(type_index_constexpr_test type_index_constexpr_test.cpp Boost::type_index)
 boost_type_index_test(type_index_ctti_print_name_test ctti_print_name.cpp Boost::type_index)
-boost_type_index_test(type_index_runtime_cast_test type_index_runtime_cast_test.cpp Boost::type_index Boost::smart_ptr)
+boost_type_index_test(type_index_runtime_cast_test type_index_runtime_cast_test.cpp Boost::type_index)
 
 boost_type_index_test(type_index_crossmodule_test testing_crossmodule.cpp Boost::type_index boost_type_index_test_lib_rtti)
 boost_type_index_test(type_index_crossmodule_anonymous_test testing_crossmodule_anonymous.cpp Boost::type_index boost_type_index_test_lib_anonymous_rtti)
@@ -78,7 +75,7 @@ foreach (testsourcefile ${EXAMPLE_FILES})
       continue()
     endif()
 
-    boost_type_index_test(type_index_${testname}_example ${testsourcefile} Boost::type_index Boost::unordered)
+    boost_type_index_test(type_index_${testname}_example ${testsourcefile} Boost::type_index)
     target_include_directories(type_index_${testname}_example PRIVATE ../examples)
 
     if (_use_import_std)
@@ -89,7 +86,7 @@ foreach (testsourcefile ${EXAMPLE_FILES})
       continue()
     endif()
 
-    boost_type_index_test(type_index_${testname}_no_rtti_example ${testsourcefile} Boost::type_index_no_rtti Boost::unordered)
+    boost_type_index_test(type_index_${testname}_no_rtti_example ${testsourcefile} Boost::type_index_no_rtti)
     target_include_directories(type_index_${testname}_no_rtti_example PRIVATE ../examples)
 endforeach()
 
diff --git a/test/cmake_subdir_test/CMakeLists.txt b/test/cmake_subdir_test/CMakeLists.txt
index e10cdb4..363347e 100644
--- a/test/cmake_subdir_test/CMakeLists.txt
+++ b/test/cmake_subdir_test/CMakeLists.txt
@@ -2,28 +2,31 @@
 # Distributed under the Boost Software License, Version 1.0.
 # See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
 
-cmake_minimum_required(VERSION 3.5...4.0)
+cmake_minimum_required(VERSION 3.28...4.4)
+
+set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
 
 project(type_index_subdir_test LANGUAGES CXX)
 
 foreach(dep IN ITEMS
-  assert
-  config
-  core
-  container_hash
-  describe
-  mp11
-  smart_ptr
-  throw_exception
-  unordered
-  predef)
+    assert
+    config
+    core
+    container_hash
+    describe
+    mp11
+    smart_ptr
+    throw_exception
+    unordered
+    predef
+)
     add_subdirectory(../../../${dep} boostorg/${dep})
 endforeach()
 
 enable_testing()
 add_subdirectory(../../ boostorg/type_index)
 
-if (BOOST_USE_MODULES)
+if(BOOST_USE_MODULES)
     add_executable(boost_type_index_module_usage ../../modules/usage_sample.cpp)
     target_link_libraries(boost_type_index_module_usage PRIVATE Boost::type_index)
     add_test(NAME boost_type_index_module_usage COMMAND boost_type_index_module_usage)
@@ -32,4 +35,19 @@ if (BOOST_USE_MODULES)
     add_executable(boost_type_index_module_usage_mu ../../modules/usage_test_mu1.cpp ../../modules/usage_test_mu2.cpp)
     target_link_libraries(boost_type_index_module_usage_mu PRIVATE Boost::type_index)
     add_test(NAME boost_type_index_module_usage_mu COMMAND boost_type_index_module_usage_mu)
+else()
+    list(APPEND RUN_TESTS_SOURCES
+        compare_ctti_stl.cpp
+        ctti_print_name.cpp
+        track_13621.cpp
+        type_index_runtime_cast_test.cpp
+        type_index_test.cpp
+    )
 endif()
+
+foreach(testsourcefile ${RUN_TESTS_SOURCES})
+    get_filename_component(testname ../${testsourcefile} NAME_WLE)
+    add_executable(${PROJECT_NAME}_${testname} ../${testsourcefile})
+    target_link_libraries(${PROJECT_NAME}_${testname} Boost::type_index)
+    add_test(NAME ${PROJECT_NAME}_${testname} COMMAND ${PROJECT_NAME}_${testname})
+endforeach()