Polish navbar and toggle styling

- Rename "Statistiques" to "Stats" in navbar across all pages
- Fix Admin button showing yellow border on click
- Fix toggle switch background to blend with dark mode container

Co-Authored-By: Claude Opus 4.5 <[email protected]>

public/css/app.css

@@ -905,6 +905,22 @@ footer {
   .btn-warning:focus,
   .btn-warning:focus-visible {
     box-shadow: 0 0 0 0.2rem rgba(29, 78, 216, 0.35);
+    outline: none;
+  }
+
+  .btn-warning:active,
+  .btn-warning.active,
+  .btn-warning:active:focus {
+    background-color: #1e40af;
+    border-color: #1e40af;
+    color: #fff;
+    box-shadow: none;
+    outline: none;
+  }
+
+  .btn-warning:focus:not(:focus-visible) {
+    box-shadow: none;
+    outline: none;
   }
 
   html[data-theme="dark"] .badge.bg-light {
@@ -1274,8 +1290,8 @@ footer {
 
   /* Dark mode: form-switch toggle visibility */
   html[data-theme="dark"] .form-switch .form-check-input {
-    background-color: #495057;
-    border-color: #6c757d;
+    background-color: rgba(255, 255, 255, 0.15);
+    border-color: rgba(255, 255, 255, 0.25);
     background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='-4 -4 8 8'%3e%3ccircle r='3' fill='rgba%28255, 255, 255, 0.7%29'/%3e%3c/svg%3e");
   }
 
@@ -1285,6 +1301,12 @@ footer {
     background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='-4 -4 8 8'%3e%3ccircle r='3' fill='%23fff'/%3e%3c/svg%3e");
   }
 
+  /* Ensure form-check/form-switch has no background (inherits from parent container) */
+  .form-check,
+  .form-switch {
+    background: transparent;
+  }
+
   .theme-toggle {
     position: relative;
     display: inline-flex;