udpate

src/apps/bg.tsx

@@ -0,0 +1,18 @@
+
+export const BG = (props: { children: React.ReactNode }) => {
+  return (
+    <div
+      style={{
+        position: 'fixed',
+        top: 0,
+        left: 0,
+        width: '100vw',
+        height: '100vh',
+        backgroundColor: 'rgba(0, 0, 0, 0.5)',
+        zIndex: -1,
+      }}
+    >
+      {props.children}
+    </div>
+  );
+}