统一加号和菜单选中样式

src/components/ConnectionDropMenu.tsx

@@ -738,7 +738,7 @@ export function ConnectionDropMenu({
       ref={menuRef}
       tabIndex={-1}
       data-tutorial="connection-drop-menu"
-      className="fixed z-100 bg-neutral-800 border border-neutral-600 rounded-lg shadow-xl overflow-hidden min-w-[160px] outline-none"
+      className="fixed z-100 select-none bg-neutral-800 border border-neutral-600 rounded-lg shadow-xl overflow-hidden min-w-[160px] outline-none"
       style={{
         left: position.x,
         top: position.y,

src/components/NodeQuickAddControls.tsx

@@ -47,7 +47,7 @@ export const NodeQuickAddControls = memo(function NodeQuickAddControls({
           aria-hidden={!visible}
           tabIndex={visible ? 0 : -1}
           title={isInput ? "Add upstream node" : "Add downstream node"}
-          className={`nodrag nopan flex h-6 w-6 items-center justify-center rounded-full border border-neutral-600 bg-neutral-800 text-neutral-200 shadow-lg shadow-black/30 transition-colors hover:border-blue-500 hover:bg-blue-600 hover:text-white focus:outline-none focus:ring-2 focus:ring-blue-500/50 ${
+          className={`nodrag nopan flex h-6 w-6 items-center justify-center rounded-full border border-neutral-500 bg-neutral-900/80 text-neutral-200 shadow-lg shadow-black/30 transition-colors hover:border-neutral-300 hover:bg-neutral-800 hover:text-white focus:outline-none focus:ring-2 focus:ring-neutral-400/40 ${
             visible ? "pointer-events-auto" : "pointer-events-none"
           }`}
           onClick={(event) => {