Reduce dialog width

Reduce the width of the welcome and expense dialogs to improve the visibility of rounded corners.

src/components/AddTransactionButton.tsx

@@ -1,4 +1,3 @@
-
 import React, { useState } from 'react';
 import { PlusIcon } from 'lucide-react';
 import { Dialog, DialogContent, DialogHeader, DialogTitle } from './ui/dialog';
@@ -100,7 +99,7 @@ const AddTransactionButton = () => {
       </div>
       
       <Dialog open={showExpenseDialog} onOpenChange={setShowExpenseDialog}>
-        <DialogContent className="sm:max-w-md">
+        <DialogContent className="w-[90%] max-w-sm mx-auto">
           <DialogHeader>
             <DialogTitle>지출 추가</DialogTitle>
           </DialogHeader>