diff --git a/proxy_chain_manager/app.py b/proxy_chain_manager/app.py
index 0d2404f..15e69c0 100644
--- a/proxy_chain_manager/app.py
+++ b/proxy_chain_manager/app.py
@@ -111,17 +111,25 @@ def main() -> None:
     # HELPERS
     # ─────────────────────────────────────────────────────────────────────────
     def _btn(parent: Any, label: str, cmd: Any, w: int = 80, h: int = 28, **kw: Any) -> ctk.CTkButton:
-        # Merge defaults so callers can override font / colors without duplicate keyword errors.
-        defaults: dict[str, Any] = {
+        # Merge styling; pass font / corner_radius explicitly so nothing duplicates
+        # inside CTkButton (font must not appear in **kwargs passed to the base class).
+        merged: dict[str, Any] = {
             "fg_color": ACCENT,
             "hover_color": ACCENT2,
             "text_color": TEXT,
-            "font": (FONT, 11),
+            **kw,
         }
-        defaults.update(kw)
+        font = merged.pop("font", (FONT, 11))
+        corner_radius = merged.pop("corner_radius", 6)
         return ctk.CTkButton(
-            parent, text=label, command=cmd, width=w, height=h,
-            corner_radius=6, **defaults,
+            parent,
+            text=label,
+            command=cmd,
+            width=w,
+            height=h,
+            corner_radius=corner_radius,
+            font=font,
+            **merged,
         )
 
     # ─────────────────────────────────────────────────────────────────────────