diff --git a/config.toml b/config.toml
index 11978e5..4385fe9 100644
--- a/config.toml
+++ b/config.toml
@@ -5,6 +5,9 @@
 # Input files — relative to repo root or absolute. Same as extract.py inputs.
 file_a = "/path/to/movie_b.mp4"
 file_b = "/path/to/movie_a.mkv"
+# Output stem names (without extension). If omitted, derived from input filename.
+stem_a = "file_a"
+stem_b = "file_b"
 # Window to extract (seconds). This is the ONLY duration needed.
 duration = 30
 # Start offset in file (seconds, 0 = file start). ffmpeg -ss before -i for fast seek.
diff --git a/extract.py b/extract.py
index d5609de..f22d7d8 100644
--- a/extract.py
+++ b/extract.py
@@ -26,6 +26,7 @@ _cfg_target_lufs = -14
 _cfg_target_tp = -1.0
 _cfg_target_lra = 11
 _cfg_audio_stream = None  # None = prompt, int = index, "skip" = no audio extraction
+_cfg_stems = [None, None]  # stem_a, stem_b from config
 try:
     try:
         import tomllib  # py3.11+
@@ -71,6 +72,10 @@ try:
                 _cfg_audio_stream = "skip"
             elif isinstance(val, (int, float)):
                 _cfg_audio_stream = int(val)
+        if _ex.get("stem_a"):
+            _cfg_stems[0] = str(_ex["stem_a"])
+        if _ex.get("stem_b"):
+            _cfg_stems[1] = str(_ex["stem_b"])
         if _cfg_inputs:
             print(f"[config] loaded {CONFIG_PATH}: duration={_cfg_duration}s start={_cfg_start}s target_fps={_cfg_target_fps}")
 except Exception as _e:
@@ -381,10 +386,11 @@ if len(valid_fps) >= 2:
 # ─── Prepare output folder ───
 os.makedirs(OUT_DIR, exist_ok=True)
 
-for INPUT_FILE in INPUT_FILES:
+for _file_idx, INPUT_FILE in enumerate(INPUT_FILES):
 
     # ─── Derive output filenames ───
-    stem = os.path.splitext(os.path.basename(INPUT_FILE))[0]
+    cfg_stem = _cfg_stems[_file_idx] if _file_idx < len(_cfg_stems) else None
+    stem = cfg_stem if cfg_stem else os.path.splitext(os.path.basename(INPUT_FILE))[0]
     video_out = os.path.join(OUT_DIR, f"{stem}_video.mkv")  # FFV1
     audio_out = os.path.join(OUT_DIR, f"{stem}_audio.wav")  # PCM f32
 
diff --git a/sync_audio_test.py b/sync_audio_test.py
index 87dc77a..91e6e17 100644
--- a/sync_audio_test.py
+++ b/sync_audio_test.py
@@ -24,7 +24,7 @@ except ModuleNotFoundError:
 
 try:
     import pyqtgraph as pg
-    from PyQt6 import QtWidgets, QtCore
+    from PyQt6 import QtWidgets, QtCore, QtGui
     HAS_PG = True
 except ImportError as e:
     print("ERROR: pyqtgraph/PyQt6 not installed — run make install", file=sys.stderr)
@@ -477,7 +477,26 @@ def main():
         print(f"ERROR: B not found {b_path}", file=sys.stderr); sys.exit(1)
 
     app = QtWidgets.QApplication(sys.argv)
-    pg.setConfigOptions(antialias=True, background="#121212", foreground="#eee")
+    # Dark theme: Fusion style + dark palette (works without kvantum)
+    app.setStyle("Fusion")
+    dark = QtWidgets.QPalette()
+    dark.setColor(QtWidgets.QPalette.ColorRole.Window, QtGui.QColor(45, 45, 45))
+    dark.setColor(QtWidgets.QPalette.ColorRole.WindowText, QtGui.QColor(220, 220, 220))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Base, QtGui.QColor(30, 30, 30))
+    dark.setColor(QtWidgets.QPalette.ColorRole.AlternateBase, QtGui.QColor(45, 45, 45))
+    dark.setColor(QtWidgets.QPalette.ColorRole.ToolTipBase, QtGui.QColor(45, 45, 45))
+    dark.setColor(QtWidgets.QPalette.ColorRole.ToolTipText, QtGui.QColor(220, 220, 220))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Text, QtGui.QColor(220, 220, 220))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Button, QtGui.QColor(45, 45, 45))
+    dark.setColor(QtWidgets.QPalette.ColorRole.ButtonText, QtGui.QColor(220, 220, 220))
+    dark.setColor(QtWidgets.QPalette.ColorRole.BrightText, QtGui.QColor(255, 50, 50))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Link, QtGui.QColor(100, 180, 255))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Highlight, QtGui.QColor(60, 120, 200))
+    dark.setColor(QtWidgets.QPalette.ColorRole.HighlightedText, QtGui.QColor(255, 255, 255))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Disabled, QtWidgets.QPalette.ColorRole.Text, QtGui.QColor(120, 120, 120))
+    dark.setColor(QtWidgets.QPalette.ColorRole.Disabled, QtWidgets.QPalette.ColorRole.ButtonText, QtGui.QColor(120, 120, 120))
+    app.setPalette(dark)
+    pg.setConfigOptions(antialias=True, background="#1e1e1e", foreground="#ddd")
     w = SyncWindow(a_path, b_path, sr=sr, method=method, device=device)
     w.show()
     sys.exit(app.exec())