diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd45e7a..fddbef8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.14.4)
 
 message(STATUS "Using CMake ${CMAKE_VERSION}")
 
@@ -61,9 +61,5 @@ endfunction(COPY_QT_BINARIES)
 
 find_package(OpenGL REQUIRED)
 
-set(HEADER_SEARCH_PATHS)
-set(SYSTEM_HEADER_SEARCH_PATHS)
-set(LINK_LIBRARIES ${Boost_LIBRARIES} Qt5::Widgets Qt5::Network Qt5::Multimedia Qt5::Charts ${OPENGL_LIBRARIES})
-
 add_subdirectory(src)
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 56c723c..44efa06 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -2,175 +2,178 @@ set(TARGET_BASE_NAME "DotaFactory")
 
 set(TARGET_APP_NAME "${TARGET_BASE_NAME}")
 set(TARGET_LIB_NAME "${TARGET_BASE_NAME}_lib")
+set(TARGET_UI_NAME "${TARGET_BASE_NAME}_ui")
 set(TARGET_TEST_NAME "${TARGET_BASE_NAME}_test")
 
-set(TARGET_LIB_HEADER_SEARCH_PATHS "${CMAKE_CURRENT_SOURCE_DIR}/lib" "${CMAKE_CURRENT_SOURCE_DIR}/external")
-set(TARGET_TEST_HEADER_SEARCH_PATHS "${CMAKE_CURRENT_SOURCE_DIR}/test")
+set(TARGET_LIB_INCLUDE_DIRS
+    "${CMAKE_CURRENT_SOURCE_DIR}/lib"
+    "${CMAKE_CURRENT_SOURCE_DIR}/external"
+)
+set(TARGET_UI_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/ui")
+set(TARGET_TEST_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/test")
 
-set(HEADER_SEARCH_PATHS ${TARGET_LIB_HEADER_SEARCH_PATHS} ${HEADER_SEARCH_PATHS})
-
-set (SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
+set(SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
 
 
-# Lib ------------------------------------------------------------
+# ============================================================
+# lib — simulation + config
+# Depends on Qt Core, toml++, tinyexpr only (no QtWidgets).
+# ============================================================
 
-SET(HDRS)
-SET(SRCS)
-SET(LIB_INCLUDE_PATH)
+set(HDRS)
+set(SRCS)
+set(LIB_INCLUDE_PATH)
 
 add_subdirectory(external)
 add_subdirectory(lib)
 
 set_source_files_properties(${EXTERNAL_FILES} PROPERTIES COMPILE_FLAGS "-w")
 
-# Find includes in corresponding build directories
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
-# Instruct CMake to run moc automatically when needed.
 set(CMAKE_AUTOMOC ON)
 
-
-SET(RELATIVE_HDRS)
+set(RELATIVE_HDRS)
 foreach (_file ${HDRS})
-	file (RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
-	list (APPEND RELATIVE_HDRS "${_relPath}")
+    file(RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
+    list(APPEND RELATIVE_HDRS "${_relPath}")
 endforeach()
 
-SET(RELATIVE_SRCS)
+set(RELATIVE_SRCS)
 foreach (_file ${SRCS})
-	file (RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
-	list (APPEND RELATIVE_SRCS "${_relPath}")
+    file(RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
+    list(APPEND RELATIVE_SRCS "${_relPath}")
 endforeach()
 
-add_files(
-	LIB_FILES
-	${RELATIVE_HDRS}
-	${RELATIVE_SRCS}
-)
-
-set(HEADER_SEARCH_PATHS ${LIB_INCLUDE_PATH} ${HEADER_SEARCH_PATHS})
+add_files(LIB_FILES ${RELATIVE_HDRS} ${RELATIVE_SRCS})
 
 add_library(${TARGET_LIB_NAME} ${LIB_FILES} ${EXTERNAL_FILES})
-
 create_source_groups(${LIB_FILES})
 create_source_groups(${EXTERNAL_FILES})
 
-UNSET(LIB_FILES)
-UNSET(RELATIVE_HDRS)
-UNSET(RELATIVE_SRCS)
-
 set_property(TARGET ${TARGET_LIB_NAME} PROPERTY CXX_STANDARD 17)
-
-set_property(
-	TARGET ${TARGET_LIB_NAME}
-	PROPERTY INCLUDE_DIRECTORIES "${HEADER_SEARCH_PATHS}"
+set_property(TARGET ${TARGET_LIB_NAME} PROPERTY INCLUDE_DIRECTORIES
+    "${TARGET_LIB_INCLUDE_DIRS}"
+    "${LIB_INCLUDE_PATH}"
 )
-
-# include external header without warnings
-target_include_directories(${TARGET_LIB_NAME} SYSTEM
-	PUBLIC "${SYSTEM_HEADER_SEARCH_PATHS}"
-)
-
-target_link_libraries(${TARGET_LIB_NAME} ${LINK_LIBRARIES})
+target_link_libraries(${TARGET_LIB_NAME} Qt5::Core)
 
 set(CMAKE_AUTOMOC OFF)
 
-set(LINK_LIBRARIES ${LINK_LIBRARIES} ${TARGET_LIB_NAME})
+unset(LIB_FILES)
+unset(RELATIVE_HDRS)
+unset(RELATIVE_SRCS)
+unset(HDRS)
+unset(SRCS)
+unset(LIB_INCLUDE_PATH)
 
 
-# App ------------------------------------------------------------
+# ============================================================
+# ui — QtWidgets + QOpenGLWidget
+# Depends on lib. No sources yet; declared as INTERFACE library.
+# When UI source files are added under src/ui/, change this to
+# a regular static library and enable AUTOMOC on the target.
+# ============================================================
+
+add_subdirectory(ui)
+
+add_library(${TARGET_UI_NAME} INTERFACE)
+
+target_link_libraries(${TARGET_UI_NAME} INTERFACE
+    ${TARGET_LIB_NAME}
+    Qt5::Widgets
+    ${OPENGL_LIBRARIES}
+    Qt5::Network
+    Qt5::Multimedia
+    Qt5::Charts
+)
+
+target_include_directories(${TARGET_UI_NAME} INTERFACE
+    "${TARGET_UI_INCLUDE_DIRS}"
+    "${TARGET_LIB_INCLUDE_DIRS}"
+)
+
+
+# ============================================================
+# app — thin main(); depends on ui
+# ============================================================
 
 set(OUTPUT_ROOT_PATH "${CMAKE_BINARY_DIR}/${TARGET_BASE_NAME}")
 
 if (WIN32)
-	COPY_QT_BINARIES("${OUTPUT_ROOT_PATH}/Debug/app/" True)
-	COPY_QT_BINARIES("${OUTPUT_ROOT_PATH}/Release/app/" False)
-	
-	string(REGEX REPLACE "/" "\\\\" BACKSLASHED_CMAKE_SOURCE_DIR ${CMAKE_SOURCE_DIR})
-	string(REGEX REPLACE "/" "\\\\" BACKSLASHED_OUTPUT_ROOT_PATH ${OUTPUT_ROOT_PATH})
-	execute_process(
-		COMMAND "cmd.exe" "/k" "rmdir" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Debug\\app\\data" & "mklink" "/d" "/j" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Debug\\app\\data" "${BACKSLASHED_CMAKE_SOURCE_DIR}\\bin\\app\\data" & exit
-		COMMAND "cmd.exe" "/k" "rmdir" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Release\\app\\data" & "mklink" "/d" "/j" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Release\\app\\data" "${BACKSLASHED_CMAKE_SOURCE_DIR}\\bin\\app\\data" & exit
-	)
+    COPY_QT_BINARIES("${OUTPUT_ROOT_PATH}/Debug/app/" True)
+    COPY_QT_BINARIES("${OUTPUT_ROOT_PATH}/Release/app/" False)
+
+    string(REGEX REPLACE "/" "\\\\" BACKSLASHED_CMAKE_SOURCE_DIR ${CMAKE_SOURCE_DIR})
+    string(REGEX REPLACE "/" "\\\\" BACKSLASHED_OUTPUT_ROOT_PATH ${OUTPUT_ROOT_PATH})
+    execute_process(
+        COMMAND "cmd.exe" "/k" "rmdir" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Debug\\app\\data" & "mklink" "/d" "/j" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Debug\\app\\data" "${BACKSLASHED_CMAKE_SOURCE_DIR}\\bin\\app\\data" & exit
+        COMMAND "cmd.exe" "/k" "rmdir" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Release\\app\\data" & "mklink" "/d" "/j" "${BACKSLASHED_OUTPUT_ROOT_PATH}\\Release\\app\\data" "${BACKSLASHED_CMAKE_SOURCE_DIR}\\bin\\app\\data" & exit
+    )
 endif ()
 
-foreach( OUTPUTCONFIG ${CMAKE_CONFIGURATION_TYPES} )
-	string( TOUPPER ${OUTPUTCONFIG} OUTPUTCONFIG )
-	set( CMAKE_RUNTIME_OUTPUT_DIRECTORY_${OUTPUTCONFIG} "${OUTPUT_ROOT_PATH}/${OUTPUTCONFIG}/app/")
-endforeach( OUTPUTCONFIG CMAKE_CONFIGURATION_TYPES )
-
+foreach (OUTPUTCONFIG ${CMAKE_CONFIGURATION_TYPES})
+    string(TOUPPER ${OUTPUTCONFIG} OUTPUTCONFIG)
+    set(CMAKE_RUNTIME_OUTPUT_DIRECTORY_${OUTPUTCONFIG} "${OUTPUT_ROOT_PATH}/${OUTPUTCONFIG}/app/")
+endforeach ()
 
+set(HDRS)
+set(SRCS)
 
 add_subdirectory(app)
 
-SET(RELATIVE_HDRS)
+set(RELATIVE_HDRS)
 foreach (_file ${HDRS})
-	file (RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
-	list (APPEND RELATIVE_HDRS "${_relPath}")
+    file(RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
+    list(APPEND RELATIVE_HDRS "${_relPath}")
 endforeach()
 
-SET(RELATIVE_SRCS)
+set(RELATIVE_SRCS)
 foreach (_file ${SRCS})
-	file (RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
-	list (APPEND RELATIVE_SRCS "${_relPath}")
+    file(RELATIVE_PATH _relPath "${SRC_DIR}" "${_file}")
+    list(APPEND RELATIVE_SRCS "${_relPath}")
 endforeach()
 
-add_files(
-	APP_FILES
-	${RELATIVE_HDRS}
-	${RELATIVE_SRCS}
-)
-
+add_files(APP_FILES ${RELATIVE_HDRS} ${RELATIVE_SRCS})
 
 add_executable(${TARGET_APP_NAME} ${APP_FILES})
-
-set_target_properties(${TARGET_APP_NAME} PROPERTIES VS_DEBUGGER_WORKING_DIRECTORY "${OUTPUT_ROOT_PATH}/$(Configuration)/app/")
-
 create_source_groups(${APP_FILES})
 
 set_property(TARGET ${TARGET_APP_NAME} PROPERTY CXX_STANDARD 17)
-
-set_property(
-	TARGET ${TARGET_APP_NAME} PROPERTY INCLUDE_DIRECTORIES 
-	"${TARGET_APP_HEADER_SEARCH_PATHS}"
-	"${HEADER_SEARCH_PATHS}" 
+set_target_properties(${TARGET_APP_NAME} PROPERTIES
+    VS_DEBUGGER_WORKING_DIRECTORY "${OUTPUT_ROOT_PATH}/$(Configuration)/app/"
 )
+target_link_libraries(${TARGET_APP_NAME} ${TARGET_UI_NAME})
 
-target_include_directories(${TARGET_APP_NAME} SYSTEM
-	PUBLIC "${SYSTEM_HEADER_SEARCH_PATHS}"
-)
-
-target_link_libraries(${TARGET_APP_NAME} ${LINK_LIBRARIES})
+unset(APP_FILES)
+unset(RELATIVE_HDRS)
+unset(RELATIVE_SRCS)
+unset(HDRS)
+unset(SRCS)
 
 
-# Test ------------------------------------------------------------
+# ============================================================
+# tests — Catch2 tests; links against lib only (no QtWidgets)
+# ============================================================
 
 add_subdirectory(test)
 
-# Find includes in corresponding build directories
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
 add_executable(${TARGET_TEST_NAME} ${TEST_FILES})
-
 create_source_groups(${TEST_FILES})
 
 set_property(TARGET ${TARGET_TEST_NAME} PROPERTY CXX_STANDARD 17)
-
-set_property(
-	TARGET ${TARGET_TEST_NAME} PROPERTY INCLUDE_DIRECTORIES 
-	"${TARGET_TEST_HEADER_SEARCH_PATHS}"
-	"${HEADER_SEARCH_PATHS}" 
+set_property(TARGET ${TARGET_TEST_NAME} PROPERTY INCLUDE_DIRECTORIES
+    "${TARGET_TEST_INCLUDE_DIRS}"
+    "${TARGET_LIB_INCLUDE_DIRS}"
 )
-
-target_include_directories(${TARGET_TEST_NAME} SYSTEM
-	PUBLIC "${SYSTEM_HEADER_SEARCH_PATHS}"
-)
-
-target_link_libraries(${TARGET_TEST_NAME} ${LINK_LIBRARIES})
+target_link_libraries(${TARGET_TEST_NAME} ${TARGET_LIB_NAME})
 
 
-# Export ------------------------------------------------------------
+# ============================================================
+# Export
+# ============================================================
 
 set(TARGET_LIB_NAME "${TARGET_LIB_NAME}" PARENT_SCOPE)
+set(TARGET_UI_NAME "${TARGET_UI_NAME}" PARENT_SCOPE)
 set(TARGET_APP_NAME "${TARGET_APP_NAME}" PARENT_SCOPE)
-set(HEADER_SEARCH_PATHS ${HEADER_SEARCH_PATHS} PARENT_SCOPE)
-set(LINK_LIBRARIES ${LINK_LIBRARIES} PARENT_SCOPE)
diff --git a/src/ui/CMakeLists.txt b/src/ui/CMakeLists.txt
new file mode 100644
index 0000000..a06e79b
--- /dev/null
+++ b/src/ui/CMakeLists.txt
@@ -0,0 +1,7 @@
+# UI source files are listed here as they are added.
+# Append headers and sources to HDRS and SRCS in PARENT_SCOPE,
+# following the same pattern used by src/lib/.
+#
+# When this directory has actual sources, the parent CMakeLists.txt
+# must be updated to convert DotaFactory_ui from an INTERFACE library
+# to a regular static library (and enable AUTOMOC on it).