diff --git a/apps/web/src/app/(portal)/marketplace/components/CategoryFilter.tsx b/apps/web/src/app/(portal)/marketplace/components/CategoryFilter.tsx
index 9106a95..ea7b11a 100644
--- a/apps/web/src/app/(portal)/marketplace/components/CategoryFilter.tsx
+++ b/apps/web/src/app/(portal)/marketplace/components/CategoryFilter.tsx
@@ -15,7 +15,6 @@ export function CategoryFilter({ categories, value, onChange }: CategoryFilterPr
     <div className="flex gap-2 overflow-x-auto pb-1">
       <button
         type="button"
-        role="button"
         onClick={() => onChange('all')}
         className={`rounded-full px-3 py-1 text-xs font-medium whitespace-nowrap transition-colors ${
           value === 'all'
@@ -29,7 +28,6 @@ export function CategoryFilter({ categories, value, onChange }: CategoryFilterPr
         <button
           key={cat}
           type="button"
-          role="button"
           onClick={() => onChange(cat)}
           className={`rounded-full px-3 py-1 text-xs font-medium whitespace-nowrap transition-colors ${
             value === cat
diff --git a/apps/web/src/app/(portal)/modules/cert-manager/components/DropZone.tsx b/apps/web/src/app/(portal)/modules/cert-manager/components/DropZone.tsx
index 18b6eb1..1379ab6 100644
--- a/apps/web/src/app/(portal)/modules/cert-manager/components/DropZone.tsx
+++ b/apps/web/src/app/(portal)/modules/cert-manager/components/DropZone.tsx
@@ -28,7 +28,7 @@ export function DropZone({ onFile, accept, currentFile, onClear }: DropZoneProps
     e.target.value = '';
   };
 
-  const handleDragOver = (e: React.DragEvent<HTMLDivElement>) => {
+  const handleDragOver = (e: React.DragEvent<HTMLButtonElement>) => {
     e.preventDefault();
     setIsDragOver(true);
   };
@@ -37,7 +37,7 @@ export function DropZone({ onFile, accept, currentFile, onClear }: DropZoneProps
     setIsDragOver(false);
   };
 
-  const handleDrop = (e: React.DragEvent<HTMLDivElement>) => {
+  const handleDrop = (e: React.DragEvent<HTMLButtonElement>) => {
     e.preventDefault();
     setIsDragOver(false);
     const file = e.dataTransfer.files?.[0];
@@ -55,43 +55,52 @@ export function DropZone({ onFile, accept, currentFile, onClear }: DropZoneProps
         className="hidden"
         onChange={handleFileChange}
       />
-      <div
-        role="button"
-        tabIndex={0}
-        onClick={handleClick}
-        onKeyDown={(e) => { if (e.key === 'Enter' || e.key === ' ') handleClick(); }}
-        onDragOver={handleDragOver}
-        onDragLeave={handleDragLeave}
-        onDrop={handleDrop}
-        className={`rounded-lg border-2 border-dashed p-8 text-center cursor-pointer transition-colors ${
-          isDragOver
-            ? 'border-primary bg-primary/5'
-            : 'border-border hover:border-primary/50'
-        }`}
-      >
-        {currentFile ? (
-          <div className="flex items-center justify-center gap-3">
+      {/* a11y/useSemanticElements: kein role="button"-div mehr -- die
+          eigentliche Flaeche ist jetzt ein echtes <button> und traegt darum
+          auch Klick UND Drag-Ereignisse (ein <div> ohne Rolle mit
+          Ereignis-Handlern waere ein statisches, nicht interaktives Element
+          und faellt unter die zurueckgestellten Regeln noStaticElement-
+          Interactions/noNoninteractiveElementInteractions). Die "Entfernen"-
+          Schaltflaeche liegt darum als Geschwister daneben, nicht mehr
+          verschachtelt in der Flaechen-Schaltflaeche -- ein <button> darf
+          kein weiteres <button> enthalten (ungueltiges Verschachteln). */}
+      <div className="relative">
+        <button
+          type="button"
+          onClick={handleClick}
+          onDragOver={handleDragOver}
+          onDragLeave={handleDragLeave}
+          onDrop={handleDrop}
+          className={`block w-full cursor-pointer rounded-lg border-2 border-dashed p-8 text-center transition-colors ${
+            isDragOver
+              ? 'border-primary bg-primary/5'
+              : 'border-border hover:border-primary/50'
+          }`}
+        >
+          {currentFile ? (
             <span className="text-sm text-foreground">
               {currentFile.name}{' '}
               <span className="text-muted-foreground">
                 ({(currentFile.size / 1024).toFixed(1)} KB)
               </span>
             </span>
-            <button
-              type="button"
-              onClick={(e) => { e.stopPropagation(); onClear(); }}
-              className="text-muted-foreground hover:text-foreground text-xs border border-border rounded px-2 py-0.5"
-            >
-              &#x2715;
-            </button>
-          </div>
-        ) : (
-          <div className="space-y-1">
-            <p className="text-sm text-muted-foreground">
-              {t('dropZone.placeholder')}
-            </p>
-            <p className="text-xs text-muted-foreground">{t('dropZone.formats')}</p>
-          </div>
+          ) : (
+            <div className="space-y-1">
+              <p className="text-sm text-muted-foreground">
+                {t('dropZone.placeholder')}
+              </p>
+              <p className="text-xs text-muted-foreground">{t('dropZone.formats')}</p>
+            </div>
+          )}
+        </button>
+        {currentFile && (
+          <button
+            type="button"
+            onClick={(e) => { e.stopPropagation(); onClear(); }}
+            className="absolute right-2 top-2 rounded border border-border bg-card px-2 py-0.5 text-xs text-muted-foreground hover:text-foreground"
+          >
+            &#x2715;
+          </button>
         )}
       </div>
     </div>
diff --git a/apps/web/src/components/admin/admin-sidebar.tsx b/apps/web/src/components/admin/admin-sidebar.tsx
index 9072ed0..02b533a 100644
--- a/apps/web/src/components/admin/admin-sidebar.tsx
+++ b/apps/web/src/components/admin/admin-sidebar.tsx
@@ -89,17 +89,17 @@ export function AdminSidebar() {
   ];
 
   return (
-    <aside
-      className="flex w-[220px] shrink-0 flex-col border-r border-sidebar-border bg-sidebar"
-      role="navigation"
-      aria-label={t('admin.label')}
-    >
+    // a11y/useSemanticElements: role="navigation" nicht auf das <aside> gehoben --
+    // das <nav> darunter trAegt die Navigationssemantik schon; ein zweites
+    // Navigations-Landmark auf dem Rahmen waere ein doppeltes Landmark fuer
+    // dieselbe Sache. Der aria-label sitzt darum am <nav>, nicht am <aside>.
+    <aside className="flex w-[220px] shrink-0 flex-col border-r border-sidebar-border bg-sidebar">
       <div className="p-4">
         <h2 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
           {t('admin.label')}
         </h2>
       </div>
-      <nav className="flex flex-col gap-1 px-3">
+      <nav className="flex flex-col gap-1 px-3" aria-label={t('admin.label')}>
         {items
           .filter((item) => item.show)
           .map((item) => (
diff --git a/apps/web/src/components/dashboard/widgets/calculator-widget.tsx b/apps/web/src/components/dashboard/widgets/calculator-widget.tsx
index fd506f0..56c61b9 100644
--- a/apps/web/src/components/dashboard/widgets/calculator-widget.tsx
+++ b/apps/web/src/components/dashboard/widgets/calculator-widget.tsx
@@ -322,7 +322,13 @@ export function CalculatorWidget({ isEditMode }: WidgetProps) {
   return (
     <div
       className="flex h-full flex-col gap-1 p-1 select-none"
-      tabIndex={0}
+      // a11y/noNoninteractiveTabindex: -1 statt 0 -- die Zahlentasten sind
+      // native <button>-Elemente und damit selbst Teil der Tab-Reihenfolge;
+      // Tastendruecke erreichen handleKeyboard weiterhin per Bubbling, sobald
+      // eine dieser Tasten fokussiert ist. -1 haelt den Container weiterhin
+      // programmatisch fokussierbar, entfernt aber den zusaetzlichen,
+      // wirkungslosen Tab-Stopp auf dem Container selbst.
+      tabIndex={-1}
       role="application"
       aria-label={t('calculator.name')}
       onKeyDown={handleKeyboard}
diff --git a/apps/web/src/components/dashboard/widgets/clock-widget.tsx b/apps/web/src/components/dashboard/widgets/clock-widget.tsx
index 3282611..dc328de 100644
--- a/apps/web/src/components/dashboard/widgets/clock-widget.tsx
+++ b/apps/web/src/components/dashboard/widgets/clock-widget.tsx
@@ -50,7 +50,6 @@ export function ClockWidget({ config }: WidgetProps) {
           verwirft clamp() im Inline-Style, der Browser bekommt die Klasse
           ohnehin — und "auto = Klasse, fest = Zahl" ist die einfachere Form. */}
       <time
-        role="time"
         data-font-mode={fixedPt === null ? 'auto' : 'fixed'}
         className="font-semibold tabular-nums leading-none text-foreground text-[clamp(12px,min(20cqw,50cqh),400px)]"
         style={fixedPt === null ? undefined : { fontSize: `${fixedPt}pt` }}
diff --git a/apps/web/src/components/dashboard/widgets/search-widget.tsx b/apps/web/src/components/dashboard/widgets/search-widget.tsx
index 1c9888f..6daeca1 100644
--- a/apps/web/src/components/dashboard/widgets/search-widget.tsx
+++ b/apps/web/src/components/dashboard/widgets/search-widget.tsx
@@ -89,7 +89,6 @@ export function SearchWidget({ instanceId, config }: WidgetProps) {
     <div className="flex h-full items-center gap-2 px-1.5">
       {/* Provider dropdown (D-14: ~120px left) */}
       <select
-        role="combobox"
         className="h-8 w-[120px] shrink-0 rounded border border-border bg-card px-2 text-sm text-foreground"
         value={selectedProviderId}
         onChange={(e) => handleProviderChange(e.target.value)}
diff --git a/apps/web/src/components/dashboard/widgets/widget-wrapper.tsx b/apps/web/src/components/dashboard/widgets/widget-wrapper.tsx
index 517213e..bd25948 100644
--- a/apps/web/src/components/dashboard/widgets/widget-wrapper.tsx
+++ b/apps/web/src/components/dashboard/widgets/widget-wrapper.tsx
@@ -35,10 +35,9 @@ export function WidgetWrapper({ widget, isEditMode, onRemove }: WidgetWrapperPro
     : 'relative h-full w-full overflow-hidden rounded-lg border border-primary/20 bg-card shadow-sm';
 
   return (
-    <div
+    <article
       className={cardClassName}
       data-widget-id={widget.id}
-      role="article"
       aria-label={definition ? t(definition.nameKey) : widget.widgetType}
     >
       {/* Edit mode: Overlay-Kopfleiste (Griff-Hinweis) mit Loesch-Knopf rechts.
@@ -117,6 +116,6 @@ export function WidgetWrapper({ widget, isEditMode, onRemove }: WidgetWrapperPro
           </div>
         )}
       </div>
-    </div>
+    </article>
   );
 }
diff --git a/apps/web/src/components/settings/settings-sidebar.tsx b/apps/web/src/components/settings/settings-sidebar.tsx
index 4d16890..8f7b560 100644
--- a/apps/web/src/components/settings/settings-sidebar.tsx
+++ b/apps/web/src/components/settings/settings-sidebar.tsx
@@ -33,18 +33,18 @@ export function SettingsSidebar() {
   };
 
   return (
-    <aside
-      className="flex w-[220px] shrink-0 flex-col border-r border-sidebar-border bg-sidebar"
-      role="navigation"
-      aria-label={t('navLabel')}
-    >
+    // a11y/useSemanticElements: role="navigation" nicht auf das <aside> gehoben --
+    // darunter stehen zwei <nav>-Bereiche (Allgemein, Dashboard); ein drittes
+    // Navigations-Landmark auf dem Rahmen waere doppelt. Jedes <nav> traegt
+    // stattdessen die Beschriftung seiner eigenen Kategorie.
+    <aside className="flex w-[220px] shrink-0 flex-col border-r border-sidebar-border bg-sidebar">
       {/* Allgemein category — above Dashboard (Surface C, 07-06) */}
       <div className="p-4 pb-2">
         <h2 className="text-xs font-semibold uppercase tracking-wider text-muted-foreground">
           {t('categoryGeneral')}
         </h2>
       </div>
-      <nav className="mb-2 flex flex-col gap-1 px-3">
+      <nav className="mb-2 flex flex-col gap-1 px-3" aria-label={t('categoryGeneral')}>
         <Link
           href="/settings/general/account"
           className={`flex items-center rounded-md px-2 py-1.5 text-sm transition-colors ${
@@ -79,7 +79,7 @@ export function SettingsSidebar() {
           {t('categoryDashboard')}
         </h2>
       </div>
-      <nav className="flex flex-col gap-1 px-3">
+      <nav className="flex flex-col gap-1 px-3" aria-label={t('categoryDashboard')}>
         {items.map((item) => (
           <Link
             key={item.href}