diff --git a/.gitignore b/.gitignore
index 66e4ec7..e6ef33c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,6 +33,7 @@ MANIFEST
 # PyInstaller
 *.manifest
 *.spec
+!build/webdrop_bridge.spec
 
 # Installer logs
 pip-log.txt
diff --git a/build/scripts/build_macos.sh b/build/scripts/build_macos.sh
index 63b7534..d5d0e29 100644
--- a/build/scripts/build_macos.sh
+++ b/build/scripts/build_macos.sh
@@ -224,8 +224,7 @@ build_executable() {
 
     python3 -m PyInstaller \
         --distpath="$DIST_DIR" \
-        --buildpath="$TEMP_BUILD" \
-        --specpath="$SPECS_DIR" \
+        --workpath="$TEMP_BUILD" \
         "$SPEC_FILE"
 
     if [ ! -d "$DIST_DIR/$APP_NAME.app" ]; then
diff --git a/build/webdrop_bridge.spec b/build/webdrop_bridge.spec
new file mode 100644
index 0000000..3c56159
--- /dev/null
+++ b/build/webdrop_bridge.spec
@@ -0,0 +1,108 @@
+# -*- mode: python ; coding: utf-8 -*-
+"""PyInstaller specification for WebDrop Bridge.
+
+This spec is shared by Windows and macOS build scripts.
+It bundles runtime resources (webapp, icons, translations) and an optional
+build-time .env file injected via WEBDROP_ENV_FILE.
+"""
+
+from pathlib import Path
+import os
+
+
+project_root = Path.cwd()
+if not (project_root / "src").exists():
+    project_root = Path(__file__).resolve().parents[1]
+
+pathex = [str(project_root / "src")]
+entry_script = str(project_root / "src" / "webdrop_bridge" / "main.py")
+
+env_file = os.environ.get("WEBDROP_ENV_FILE")
+bundle_id = os.environ.get("WEBDROP_BUNDLE_ID", "de.him_tools.webdrop-bridge")
+bundle_version = os.environ.get("WEBDROP_VERSION", "0.0.0")
+
+asset_prefix = os.environ.get("WEBDROP_ASSET_PREFIX")
+exe_name = os.environ.get("WEBDROP_EXE_NAME", asset_prefix or "WebDropBridge")
+app_name = asset_prefix or exe_name
+
+icon_ico_default = project_root / "resources" / "icons" / "app.ico"
+icon_icns_default = project_root / "resources" / "icons" / "app.icns"
+icon_ico = Path(os.environ.get("WEBDROP_ICON_ICO", str(icon_ico_default)))
+icon_icns = Path(os.environ.get("WEBDROP_ICON_ICNS", str(icon_icns_default)))
+
+datas = [
+    (str(project_root / "resources"), "resources"),
+    (str(project_root / "webapp"), "webapp"),
+]
+
+ui_dir = project_root / "src" / "webdrop_bridge" / "ui"
+for js_file in ui_dir.glob("*.js"):
+    datas.append((str(js_file), "webdrop_bridge/ui"))
+
+if env_file and Path(env_file).exists():
+    datas.append((env_file, "."))
+
+hiddenimports = [
+    "PySide6.QtWebEngineCore",
+    "PySide6.QtWebEngineWidgets",
+    "PySide6.QtWebChannel",
+]
+
+a = Analysis(
+    [entry_script],
+    pathex=pathex,
+    binaries=[],
+    datas=datas,
+    hiddenimports=hiddenimports,
+    hookspath=[],
+    hooksconfig={},
+    runtime_hooks=[],
+    excludes=[],
+    noarchive=False,
+    optimize=0,
+)
+
+pyz = PYZ(a.pure)
+
+exe = EXE(
+    pyz,
+    a.scripts,
+    [],
+    exclude_binaries=True,
+    name=exe_name,
+    debug=False,
+    bootloader_ignore_signals=False,
+    strip=False,
+    upx=True,
+    console=False,
+    disable_windowed_traceback=False,
+    argv_emulation=False,
+    target_arch=None,
+    codesign_identity=None,
+    entitlements_file=None,
+    icon=str(icon_ico) if icon_ico.exists() else None,
+)
+
+coll = COLLECT(
+    exe,
+    a.binaries,
+    a.zipfiles,
+    a.datas,
+    strip=False,
+    upx=True,
+    upx_exclude=[],
+    name=exe_name,
+)
+
+app = BUNDLE(
+    coll,
+    name=f"{app_name}.app",
+    icon=str(icon_icns) if icon_icns.exists() else None,
+    bundle_identifier=bundle_id,
+    info_plist={
+        "CFBundleName": app_name,
+        "CFBundleDisplayName": app_name,
+        "CFBundleShortVersionString": bundle_version,
+        "CFBundleVersion": bundle_version,
+    },
+)
\ No newline at end of file