update app.css home.jsx to adjust homepage layout

src/components/Home.jsx

@@ -67,7 +67,7 @@ function Home({ setActiveTab, role, setRole }) {
       }
     } else {
       const pwd = window.prompt("Enter Admin Password:");
-      if (pwd === "admin123") {
+      if (pwd === "123") {
         try {
           await fetch('/api/history', { method: 'DELETE' });
           const res = await fetch('/test_data.json');
@@ -96,23 +96,23 @@ function Home({ setActiveTab, role, setRole }) {
       <h1>FocusGuard</h1>
       <p>Your productivity monitor assistant.</p>
 
-      {/* 选项按钮组，全部采用和谐的蓝色按钮 (btn-main) */}
-      <div style={{ display: 'flex', flexDirection: 'column', gap: '15px', alignItems: 'center', marginTop: '30px' }}>
+      {/* 使用全新的 2x2 网格容器 */}
+      <div className="home-button-grid">
         
-        <button className="btn-main" onClick={handleNewStart} style={{ width: '250px' }}>
+        <button className="btn-main" onClick={handleNewStart}>
           Start Focus
         </button>
 
-        <button className="btn-main" onClick={handleAutoImport} style={{ width: '250px' }}>
+        <button className="btn-main" onClick={handleAutoImport}>
           Auto Import History
         </button>
 
-        <button className="btn-main" onClick={() => fileInputRef.current.click()} style={{ width: '250px' }}>
+        <button className="btn-main" onClick={() => fileInputRef.current.click()}>
           Manual Import History
         </button>
         <input type="file" ref={fileInputRef} style={{ display: 'none' }} accept=".json" onChange={handleFileChange} />
 
-        <button className="btn-main" onClick={handleAdminToggle} style={{ width: '250px' }}>
+        <button className="btn-main" onClick={handleAdminToggle}>
           {role === 'admin' ? 'Switch to User Mode' : 'Admin Login'}
         </button>