Adjust card alignment

The cards were slightly off-center, with uneven spacing on the left and right. This commit adjusts the alignment to ensure the cards are centered properly.

src/pages/Index.tsx

@@ -1,4 +1,3 @@
-
 import React, { useState, useEffect } from 'react';
 import NavBar from '@/components/NavBar';
 import AddTransactionButton from '@/components/AddTransactionButton';
@@ -140,7 +139,7 @@ const Index = () => {
 
   return (
     <div className="min-h-screen bg-neuro-background pb-24">
-      <div className={`mx-auto px-4 ${isMobile ? 'w-full' : 'max-w-lg'}`}>
+      <div className="mx-auto px-4 desktop-container">
         <Header />
 
         {/* 목표 진행 상황 */}