Add shell accessibility landmarks

docs/tables_frontend_overhaul_implementation_plan.md

@@ -44,6 +44,7 @@ It is intentionally implementation-focused:
 | 2026-03-21 | P1.4 | Completed | Added shared browser-storage wrappers, persisted theme mode in `localStorage`, and initialize/apply theme state from the layout on interactive render. |
 | 2026-03-21 | P1.5 | Completed | Replaced the permanent sidebar layout with a sticky top app shell and mobile bottom navigation backed by dedicated shell components. |
 | 2026-03-21 | P1.6 | Completed | Added explicit shell slots for nav, omnibox, shortcuts, and utilities; switched shell navigation to `Play`, `Tables`, `Curation`, and `Tools`; and wired the first live theme control into the shell. |
+| 2026-03-21 | P1.7 | Completed | Added a shell-level skip link and tightened the top-level header, navigation, and main landmarks around the new shell structure. |
 
 ### Lessons Learned
 
@@ -57,6 +58,7 @@ It is intentionally implementation-focused:
 - Shared UI state events in Blazor should stay synchronous unless the event contract is async-aware. Layout refresh can be triggered safely with `InvokeAsync(StateHasChanged)` from a synchronous handler.
 - Extracting shell markup into dedicated components is lower-risk than continuing to evolve `MainLayout.razor` directly. It isolates responsive frame work from page content and keeps later nav changes localized.
 - Once a Razor component exposes multiple named `RenderFragment` parameters, the page body must be passed explicitly through `<ChildContent>`. That pattern is now the baseline for shell composition here.
+- Accessibility work is cheaper when the shell owns the landmarks. Adding skip links and nav/main structure at the shell layer avoids repeating that work page by page.
 
 ## Target Outcomes
 
@@ -264,7 +266,7 @@ Create the implementation foundation so the visual overhaul does not start with
 | `P1.4` | Completed | Theme mode now persists through a shared storage service and is applied from the layout during interactive startup. |
 | `P1.5` | Completed | The sidebar is gone; pages now render inside a sticky top-shell with a mobile bottom nav. |
 | `P1.6` | Completed | The shell now has explicit nav, omnibox, shortcut, and utility slots, plus a live theme selector and destination-model navigation. |
-| `P1.7` | Pending | Skip link and landmark work will land with the shell markup. |
+| `P1.7` | Completed | The shell now exposes a skip link and explicit header/nav/main landmarks. |
 | `P1.8` | Pending | Tools-specific shell emphasis is final Phase 1 polish. |
 
 ### Goal

src/RolemasterDb.App/Components/Shell/AppShell.razor

@@ -1,4 +1,6 @@
 <div class="app-shell">
+    <a class="skip-link" href="#app-main">Skip to main content</a>
+
     <header class="app-shell-header">
         <div class="app-shell-bar">
             <div class="app-shell-brand-block">
@@ -18,7 +20,7 @@
                 }
             </div>
 
-            <div class="app-shell-header-nav">
+            <nav class="app-shell-header-nav" aria-label="Primary">
                 @if (PrimaryNavContent is null)
                 {
                     <ShellPrimaryNav />
@@ -27,7 +29,7 @@
                 {
                     @PrimaryNavContent
                 }
-            </div>
+            </nav>
 
             <div class="app-shell-header-omnibox">
                 @if (OmniboxContent is not null)
@@ -43,9 +45,9 @@
 
         @if (ShortcutContent is not null)
         {
-            <div class="app-shell-shortcuts">
+            <nav class="app-shell-shortcuts" aria-label="Pinned and recent shortcuts">
                 @ShortcutContent
-            </div>
+            </nav>
         }
     </header>
 

src/RolemasterDb.App/Components/Shell/AppShell.razor.css

@@ -4,6 +4,24 @@
     flex-direction: column;
 }
 
+.skip-link {
+    position: absolute;
+    left: 1rem;
+    top: -3rem;
+    z-index: 80;
+    padding: 0.75rem 1rem;
+    border-radius: 999px;
+    background: var(--accent-5);
+    color: var(--text-on-accent);
+    text-decoration: none;
+    box-shadow: var(--shadow-1);
+    transition: top 140ms ease;
+}
+
+.skip-link:focus {
+    top: 1rem;
+}
+
 .app-shell-header {
     position: sticky;
     top: 0;