diff --git a/CMakeLists.txt b/CMakeLists.txt
index 84c86400..16d12f22 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -157,11 +157,6 @@ if(WIN32 OR APPLE)
     set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
 endif()
 
-# Build number define
-if(BUILD_NUMBER)
-    add_compile_definitions("BUILD_NUMBER=\"${BUILD_NUMBER}\"")
-endif()
-
 # --- Subdirectories (dependency order) ---
 add_subdirectory(third_party)
 add_subdirectory(compressed_archive)
diff --git a/YACReader/CMakeLists.txt b/YACReader/CMakeLists.txt
index a6fcded6..ea9322df 100644
--- a/YACReader/CMakeLists.txt
+++ b/YACReader/CMakeLists.txt
@@ -45,6 +45,7 @@ qt_add_executable(YACReader WIN32
     ${PROJECT_SOURCE_DIR}/common/themes/theme_manager.h
     ${PROJECT_SOURCE_DIR}/common/themes/theme_manager.cpp
 )
+yacreader_apply_build_options(YACReader)
 
 target_include_directories(YACReader PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}
diff --git a/YACReaderLibrary/CMakeLists.txt b/YACReaderLibrary/CMakeLists.txt
index d8586d48..38faf04c 100644
--- a/YACReaderLibrary/CMakeLists.txt
+++ b/YACReaderLibrary/CMakeLists.txt
@@ -31,6 +31,7 @@ target_include_directories(library_common PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/db
 )
+yacreader_apply_build_options(library_common)
 target_link_libraries(library_common PUBLIC
     Qt6::Core
     Qt6::Core5Compat
@@ -62,6 +63,7 @@ target_include_directories(db_helper PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/db
 )
+yacreader_apply_build_options(db_helper)
 target_link_libraries(db_helper PUBLIC
     Qt6::Core
     Qt6::Sql
@@ -179,6 +181,7 @@ qt_add_executable(YACReaderLibrary WIN32
     ${PROJECT_SOURCE_DIR}/common/themes/theme_manager.h
     ${PROJECT_SOURCE_DIR}/common/themes/theme_manager.cpp
 )
+yacreader_apply_build_options(YACReaderLibrary)
 
 # macOS-specific sources
 if(APPLE)
diff --git a/YACReaderLibrary/comic_vine/CMakeLists.txt b/YACReaderLibrary/comic_vine/CMakeLists.txt
index 947d01b6..382e3f0f 100644
--- a/YACReaderLibrary/comic_vine/CMakeLists.txt
+++ b/YACReaderLibrary/comic_vine/CMakeLists.txt
@@ -54,6 +54,7 @@ target_include_directories(comic_vine PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/model
 )
+yacreader_apply_build_options(comic_vine)
 # App-specific theme.h needed for themable.h → theme_manager.h → theme.h chain
 target_include_directories(comic_vine PRIVATE
     ${PROJECT_SOURCE_DIR}/YACReaderLibrary/themes
diff --git a/YACReaderLibrary/server/CMakeLists.txt b/YACReaderLibrary/server/CMakeLists.txt
index af7b337e..839072ef 100644
--- a/YACReaderLibrary/server/CMakeLists.txt
+++ b/YACReaderLibrary/server/CMakeLists.txt
@@ -67,6 +67,7 @@ target_include_directories(server PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}/controllers
     ${CMAKE_CURRENT_SOURCE_DIR}/controllers/v2
 )
+yacreader_apply_build_options(server)
 target_compile_definitions(server PUBLIC SERVER_VERSION_NUMBER="2.1")
 if(UNIX AND NOT APPLE)
     target_compile_definitions(server PRIVATE
diff --git a/YACReaderLibraryServer/CMakeLists.txt b/YACReaderLibraryServer/CMakeLists.txt
index efaf364a..ed45d453 100644
--- a/YACReaderLibraryServer/CMakeLists.txt
+++ b/YACReaderLibraryServer/CMakeLists.txt
@@ -7,6 +7,7 @@ qt_add_executable(YACReaderLibraryServer
     libraries_updater.h
     libraries_updater.cpp
 )
+yacreader_apply_build_options(YACReaderLibraryServer)
 
 target_include_directories(YACReaderLibraryServer PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}
@@ -18,6 +19,9 @@ target_compile_definitions(YACReaderLibraryServer PRIVATE
     SERVER_RELEASE
     YACREADER_LIBRARY
 )
+if(BUILD_NUMBER)
+    target_compile_definitions(YACReaderLibraryServer PRIVATE "BUILD_NUMBER=\"${BUILD_NUMBER}\"")
+endif()
 
 # Translations
 qt_add_translations(YACReaderLibraryServer
diff --git a/cmake/CompilerOptions.cmake b/cmake/CompilerOptions.cmake
index c90fa6f8..429cf995 100644
--- a/cmake/CompilerOptions.cmake
+++ b/cmake/CompilerOptions.cmake
@@ -1,13 +1,31 @@
-# Compiler options for YACReader
+# Compiler policy for YACReader-owned targets.
+# Keep this target internal so third-party code does not inherit our rules.
+add_library(yacreader_build_options INTERFACE)
+
+target_compile_definitions(yacreader_build_options INTERFACE
+    QT_DISABLE_DEPRECATED_UP_TO=0x060400
+)
 
 if(MSVC)
-    # Prevent windows.h from defining min/max macros that conflict with
-    # std::min, std::max, std::numeric_limits<T>::max(), etc.
-    add_compile_definitions(NOMINMAX)
+    target_compile_definitions(yacreader_build_options INTERFACE
+        # Prevent windows.h from defining min/max macros that conflict with
+        # std::min, std::max, std::numeric_limits<T>::max(), etc.
+        NOMINMAX
+    )
 
-    # /Zc:__cplusplus: report correct __cplusplus value
-    # /permissive-: strict standard conformance
-    add_compile_options(/Zc:__cplusplus /permissive-)
+    target_compile_options(yacreader_build_options INTERFACE
+        # /Zc:__cplusplus: report correct __cplusplus value
+        # /permissive-: strict standard conformance
+        $<$<COMPILE_LANG_AND_ID:CXX,MSVC>:/Zc:__cplusplus>
+        $<$<COMPILE_LANG_AND_ID:CXX,MSVC>:/permissive->
+    )
 endif()
 
-add_compile_definitions(QT_DISABLE_DEPRECATED_UP_TO=0x060400)
+function(yacreader_apply_build_options)
+    foreach(target_name IN LISTS ARGN)
+        if(NOT TARGET "${target_name}")
+            message(FATAL_ERROR "yacreader_apply_build_options(): unknown target '${target_name}'")
+        endif()
+        target_link_libraries("${target_name}" PRIVATE yacreader_build_options)
+    endforeach()
+endfunction()
diff --git a/common/CMakeLists.txt b/common/CMakeLists.txt
index d8017a65..ba76f7cf 100644
--- a/common/CMakeLists.txt
+++ b/common/CMakeLists.txt
@@ -18,6 +18,7 @@ target_include_directories(yr_global PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_BINARY_DIR}
 )
+yacreader_apply_build_options(yr_global)
 target_link_libraries(yr_global PUBLIC Qt6::Core)
 if(UNIX AND NOT APPLE)
     target_compile_definitions(yr_global PRIVATE
@@ -30,6 +31,7 @@ add_library(naturalsort STATIC
     qnaturalsorting.cpp
 )
 target_include_directories(naturalsort PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(naturalsort)
 target_link_libraries(naturalsort PUBLIC Qt6::Core)
 
 # --- concurrent_queue ---
@@ -38,6 +40,7 @@ add_library(concurrent_queue STATIC
     concurrent_queue.cpp
 )
 target_include_directories(concurrent_queue PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(concurrent_queue)
 target_link_libraries(concurrent_queue PUBLIC Qt6::Core)
 
 # --- worker (header-only thread helpers) ---
@@ -66,6 +69,7 @@ add_library(common_all STATIC
     global_info_provider.cpp
 )
 target_include_directories(common_all PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(common_all)
 target_link_libraries(common_all PUBLIC
     Qt6::Core
     Qt6::Gui
@@ -82,6 +86,7 @@ add_library(comic_backend STATIC
     comic.cpp
     pdf_comic.h
 )
+yacreader_apply_build_options(comic_backend)
 
 # PDF source depends on backend
 if(PDF_BACKEND STREQUAL "pdfkit")
@@ -144,6 +149,7 @@ target_include_directories(common_gui PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}/themes
     ${CMAKE_CURRENT_SOURCE_DIR}/themes/shared
 )
+yacreader_apply_build_options(common_gui)
 
 target_link_libraries(common_gui PUBLIC
     Qt6::Core
@@ -176,6 +182,7 @@ target_include_directories(rhi_flow_reader PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/rhi
 )
+yacreader_apply_build_options(rhi_flow_reader)
 target_compile_definitions(rhi_flow_reader PRIVATE YACREADER)
 target_link_libraries(rhi_flow_reader PUBLIC
     Qt6::Core
@@ -200,6 +207,7 @@ target_include_directories(rhi_flow_library PUBLIC
     ${CMAKE_CURRENT_SOURCE_DIR}
     ${CMAKE_CURRENT_SOURCE_DIR}/rhi
 )
+yacreader_apply_build_options(rhi_flow_library)
 target_compile_definitions(rhi_flow_library PRIVATE YACREADER_LIBRARY)
 target_link_libraries(rhi_flow_library PUBLIC
     Qt6::Core
diff --git a/compressed_archive/CMakeLists.txt b/compressed_archive/CMakeLists.txt
index a5f5ba5c..6fd5adcf 100644
--- a/compressed_archive/CMakeLists.txt
+++ b/compressed_archive/CMakeLists.txt
@@ -2,6 +2,7 @@
 # Switched on DECOMPRESSION_BACKEND: unarr | 7zip | libarchive
 
 add_library(cbx_backend STATIC)
+yacreader_apply_build_options(cbx_backend)
 
 if(DECOMPRESSION_BACKEND STREQUAL "unarr")
     message(STATUS "Decompression backend: unarr")
@@ -88,14 +89,14 @@ elseif(DECOMPRESSION_BACKEND STREQUAL "7zip")
 
     if(APPLE)
         target_compile_definitions(cbx_backend PRIVATE
-            _FILE_OFFSET_BITS=64 _LARGEFILE_SOURCE NDEBUG _REENTRANT
+            _FILE_OFFSET_BITS=64 _LARGEFILE_SOURCE _REENTRANT
             ENV_UNIX _7ZIP_LARGE_PAGES ENV_MACOSX _TCHAR_DEFINED
             UNICODE _UNICODE UNIX_USE_WIN_FILE)
         target_link_libraries(cbx_backend PRIVATE
             "-framework IOKit" "-framework CoreFoundation")
     elseif(UNIX)
         target_compile_definitions(cbx_backend PRIVATE
-            _FILE_OFFSET_BITS=64 _LARGEFILE_SOURCE NDEBUG _REENTRANT
+            _FILE_OFFSET_BITS=64 _LARGEFILE_SOURCE _REENTRANT
             ENV_UNIX _7ZIP_LARGE_PAGES UNICODE _UNICODE UNIX_USE_WIN_FILE)
     endif()
 
diff --git a/custom_widgets/CMakeLists.txt b/custom_widgets/CMakeLists.txt
index 84590dad..4e35aa05 100644
--- a/custom_widgets/CMakeLists.txt
+++ b/custom_widgets/CMakeLists.txt
@@ -38,11 +38,15 @@ endif()
 # --- custom_widgets_reader (YACReader-specific) ---
 add_library(custom_widgets_reader STATIC ${WIDGETS_COMMON_SOURCES})
 target_include_directories(custom_widgets_reader PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(custom_widgets_reader)
 # App-specific theme.h needed because themable.h → theme_manager.h → theme.h
 target_include_directories(custom_widgets_reader PRIVATE
     ${PROJECT_SOURCE_DIR}/YACReader/themes
 )
 target_compile_definitions(custom_widgets_reader PRIVATE YACREADER)
+if(BUILD_NUMBER)
+    target_compile_definitions(custom_widgets_reader PRIVATE "BUILD_NUMBER=\"${BUILD_NUMBER}\"")
+endif()
 target_link_libraries(custom_widgets_reader PUBLIC
     Qt6::Core
     Qt6::Widgets
@@ -83,6 +87,7 @@ add_library(custom_widgets_library STATIC
     ${LIBRARY_EXTRA_WIDGETS}
 )
 target_include_directories(custom_widgets_library PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(custom_widgets_library)
 # App-specific theme.h + YACReaderLibrary headers needed by macosx_toolbar
 target_include_directories(custom_widgets_library PRIVATE
     ${PROJECT_SOURCE_DIR}/YACReaderLibrary/themes
@@ -90,6 +95,9 @@ target_include_directories(custom_widgets_library PRIVATE
     ${PROJECT_SOURCE_DIR}/YACReaderLibrary/db
 )
 target_compile_definitions(custom_widgets_library PRIVATE YACREADER_LIBRARY)
+if(BUILD_NUMBER)
+    target_compile_definitions(custom_widgets_library PRIVATE "BUILD_NUMBER=\"${BUILD_NUMBER}\"")
+endif()
 target_link_libraries(custom_widgets_library PUBLIC
     Qt6::Core
     Qt6::Widgets
diff --git a/image_processing/CMakeLists.txt b/image_processing/CMakeLists.txt
index 7421e7e1..86079aa4 100644
--- a/image_processing/CMakeLists.txt
+++ b/image_processing/CMakeLists.txt
@@ -5,5 +5,6 @@ add_library(image_processing STATIC
 )
 
 target_include_directories(image_processing PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(image_processing)
 
-target_link_libraries(image_processing PRIVATE Qt::Gui)
+target_link_libraries(image_processing PRIVATE Qt6::Gui)
diff --git a/shortcuts_management/CMakeLists.txt b/shortcuts_management/CMakeLists.txt
index 3c893d06..88fab140 100644
--- a/shortcuts_management/CMakeLists.txt
+++ b/shortcuts_management/CMakeLists.txt
@@ -17,6 +17,7 @@ set(SHORTCUTS_SOURCES
 # --- shortcuts_reader (YACREADER define) ---
 add_library(shortcuts_reader STATIC ${SHORTCUTS_SOURCES})
 target_include_directories(shortcuts_reader PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(shortcuts_reader)
 # App-specific theme.h needed because themable.h → theme_manager.h → theme.h
 target_include_directories(shortcuts_reader PRIVATE
     ${PROJECT_SOURCE_DIR}/YACReader/themes
@@ -27,6 +28,7 @@ target_link_libraries(shortcuts_reader PUBLIC Qt6::Core Qt6::Widgets yr_global c
 # --- shortcuts_library (YACREADER_LIBRARY define) ---
 add_library(shortcuts_library STATIC ${SHORTCUTS_SOURCES})
 target_include_directories(shortcuts_library PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+yacreader_apply_build_options(shortcuts_library)
 target_include_directories(shortcuts_library PRIVATE
     ${PROJECT_SOURCE_DIR}/YACReaderLibrary/themes
 )
diff --git a/tests/compressed_archive_test/CMakeLists.txt b/tests/compressed_archive_test/CMakeLists.txt
index 4f0e1c47..ad7f4ac8 100644
--- a/tests/compressed_archive_test/CMakeLists.txt
+++ b/tests/compressed_archive_test/CMakeLists.txt
@@ -3,6 +3,7 @@
 qt_add_executable(compressed_archive_test
     main.cpp
 )
+yacreader_apply_build_options(compressed_archive_test)
 target_link_libraries(compressed_archive_test PRIVATE
     Qt6::Core
     cbx_backend
diff --git a/tests/concurrent_queue_test/CMakeLists.txt b/tests/concurrent_queue_test/CMakeLists.txt
index 380e52b5..4df4df02 100644
--- a/tests/concurrent_queue_test/CMakeLists.txt
+++ b/tests/concurrent_queue_test/CMakeLists.txt
@@ -3,6 +3,7 @@
 qt_add_executable(concurrent_queue_test
     concurrent_queue_test.cpp
 )
+yacreader_apply_build_options(concurrent_queue_test)
 target_link_libraries(concurrent_queue_test PRIVATE
     Qt6::Core
     Qt6::Test