create project

frontend/lib/widgets/category_icon.dart

@@ -0,0 +1,40 @@
+import 'package:flutter/material.dart';
+import '../theme/colors.dart';
+
+class CategoryIcon extends StatelessWidget {
+  final String emoji;
+  final String category;
+  final double size;
+
+  const CategoryIcon({
+    super.key,
+    required this.emoji,
+    required this.category,
+    this.size = 40,
+  });
+
+  Color _bgColor() {
+    switch (category) {
+      case '餐饮': return AppColors.brand.withOpacity(0.08);
+      case '交通': return AppColors.brandLight.withOpacity(0.08);
+      case '购物': return AppColors.brand.withOpacity(0.06);
+      case '医疗': return AppColors.expense.withOpacity(0.06);
+      case '工资': return AppColors.income.withOpacity(0.08);
+      default: return AppColors.textSecondary.withOpacity(0.08);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: size,
+      height: size,
+      decoration: BoxDecoration(
+        color: _bgColor(),
+        shape: BoxShape.circle,
+        boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 4, offset: Offset(0, 2))],
+      ),
+      child: Center(child: Text(emoji, style: TextStyle(fontSize: size * 0.45))),
+    );
+  }
+}