Use PageHeader throughout the system

WebApp/Components/Features/Teams/Create.razor

@@ -1,14 +1,26 @@
 @page "/teams/create"
 @attribute [Authorize]
 @using Microsoft.EntityFrameworkCore
+@using WebApp.Components.Shared.Components
 @inject AppDbContext Context
 @inject NavigationManager NavigationManager
 
-<PageTitle>Create Team - TSA Chapter Organizer</PageTitle>
+@if (_events is null)
+{
+    <p><em>Loading...</em></p>
+    return;
+}
 
-<MudText Typo="Typo.h3">Create</MudText>
-<MudText Typo="Typo.h4">Team</MudText>
-<MudDivider />
+<PageHeader
+    Title="Create"
+    Subtitle="Team"
+    ShowBackButton="true"
+    BackButtonUrl="/teams">
+    <ActionButtons>
+        <MudButton OnClick="AddTeam" Variant="Variant.Filled" Color="Color.Primary">Add</MudButton>
+        <MudButton Href="/teams" Variant="Variant.Text">Cancel</MudButton>
+    </ActionButtons>
+</PageHeader>
 
 <EditForm method="post" Model="Team" OnValidSubmit="AddTeam" FormName="create" Enhance>
     <AntiforgeryToken />
@@ -23,17 +35,18 @@
                         <MudSelectItem T="EventDefinition" Value="@(evt)"></MudSelectItem>
                     }
                 </MudSelect>
-                @if (_existingTeams?.Count == 1)
+                @switch (_existingTeams?.Count)
                 {
-                    <MudAlert Severity="Severity.Info" Class="my-2">
-                        A team for @Team.Event.Name already exists. This will be team 2, and the existing team will become team 1.
-                    </MudAlert>
-                }
-                else if (_existingTeams?.Count >= 2)
-                {
-                    <MudAlert Severity="Severity.Error" Class="my-2">
-                        Two teams for @Team.Event.Name already exist. Cannot create a third team.
-                    </MudAlert>
+                    case 1:
+                        <MudAlert Severity="Severity.Info" Class="my-2">
+                            A team for @Team.Event.Name already exists. This will be team 2, and the existing team will become team 1.
+                        </MudAlert>
+                        break;
+                    case >= 2:
+                        <MudAlert Severity="Severity.Error" Class="my-2">
+                            Two teams for @Team.Event.Name already exist. Cannot create a third team.
+                        </MudAlert>
+                        break;
                 }
 
                 <MudDivider Class="my-4" />
@@ -55,8 +68,6 @@
     {
         <MudAlert Severity="Severity.Error" Class="mt-3">@_errorMessage</MudAlert>
     }
-    <MudButton StartIcon="@Icons.Material.Filled.ArrowBack" Href="students">Back</MudButton>
-    <MudButton StartIcon="@Icons.Material.Filled.Add" OnClick="AddTeam">Add</MudButton>
 </EditForm>
 
 @code {