fix：导航栏交互和UI

lib/features/institutions/institutions_page.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
-import 'package:shadcn_ui/shadcn_ui.dart';
 
 import '../../data/api/report_data_source.dart';
 import '../../data/content_providers.dart';
@@ -43,9 +42,7 @@ class InstitutionsPage extends HookConsumerWidget {
           ),
           children: [
             const PageHeader(title: '机构', subtitle: '可获取研报的机构'),
-            const SizedBox(height: YantingSpacing.x3),
-            const ShadSeparator.horizontal(),
-            const SizedBox(height: YantingSpacing.x3),
+            const SizedBox(height: YantingSpacing.cardGap),
             for (final item in sorted) ...[
               InstitutionCard(
                 institution: item,