diff --git a/frontend/src/detail/DetailPanel.jsx b/frontend/src/detail/DetailPanel.jsx
index 2eae843..f0fb139 100644
--- a/frontend/src/detail/DetailPanel.jsx
+++ b/frontend/src/detail/DetailPanel.jsx
@@ -217,6 +217,7 @@ const PreviewStack = ({
   emptyMessage = 'Preview unavailable',
   onItemActivate,
   onOpenPreview,
+  onZoomPreview,
   activeItemId = null,
 }) => {
   if (!items.length) {
@@ -249,7 +250,11 @@ const PreviewStack = ({
               zIndex: preparedItems.length - index,
               transform,
             }}
-            aria-hidden={hasMultiple && !onItemActivate && !onOpenPreview ? 'true' : undefined}
+            aria-hidden={
+              hasMultiple && !onItemActivate && !onOpenPreview && !onZoomPreview
+                ? 'true'
+                : undefined
+            }
           >
             <img
               src={entry.url}
@@ -257,19 +262,31 @@ const PreviewStack = ({
               className="preview-stack__image"
               onClick={(event) => {
                 event.stopPropagation();
-                if (isFront && onOpenPreview) {
-                  onOpenPreview(entry.id);
+                if (isFront) {
+                  if (onZoomPreview) {
+                    onZoomPreview(entry);
+                  } else if (onOpenPreview) {
+                    onOpenPreview(entry.id);
+                  } else if (onItemActivate) {
+                    onItemActivate(entry.id);
+                  }
                 } else if (onItemActivate) {
                   onItemActivate(entry.id);
                 }
               }}
               onKeyDown={(event) => {
-                if (!onItemActivate && !onOpenPreview) return;
+                if (!onItemActivate && !onOpenPreview && !onZoomPreview) return;
                 if (event.key === 'Enter' || event.key === ' ') {
                   event.preventDefault();
                   event.stopPropagation();
-                  if (isFront && onOpenPreview) {
-                    onOpenPreview(entry.id);
+                  if (isFront) {
+                    if (onZoomPreview) {
+                      onZoomPreview(entry);
+                    } else if (onOpenPreview) {
+                      onOpenPreview(entry.id);
+                    } else {
+                      onItemActivate?.(entry.id);
+                    }
                   } else {
                     onItemActivate?.(entry.id);
                   }
@@ -310,6 +327,11 @@ const DetailPanel = ({
 }) => {
   const selectedCount = selectedDocuments.length;
   const singleDoc = selectedCount === 1 ? selectedDocuments[0] : null;
+  const singleDocId = singleDoc?.id || null;
+  const selectionKey = useMemo(
+    () => selectedDocuments.map((doc) => doc?.id ?? '').join('|'),
+    [selectedDocuments],
+  );
 
   const singleDownloadHref = useMemo(() => {
     if (!singleDoc) return null;
@@ -328,6 +350,7 @@ const DetailPanel = ({
   const [ocrUrl, setOcrUrl] = useState(null);
   const [ocrLoading, setOcrLoading] = useState(false);
   const [ocrError, setOcrError] = useState(null);
+  const [zoomedPreview, setZoomedPreview] = useState(null);
 
   useEffect(() => {
     if (!singleDoc) {
@@ -357,6 +380,10 @@ const DetailPanel = ({
     setOcrUrl(null);
   }, [singleDoc?.id]);
 
+  useEffect(() => {
+    setZoomedPreview(null);
+  }, [selectionKey]);
+
   const startTitleEdit = useCallback(() => {
     if (!singleDoc) return;
     setTitleEditDocId(singleDoc.id);
@@ -519,6 +546,7 @@ const DetailPanel = ({
   }, [selectedDocuments]);
 
   const stackTopDocument = stackDocuments[0] || null;
+  const stackTopDocId = stackTopDocument?.id || null;
   const stackPreviewNavigator = useAssetNavigator({
     document: stackTopDocument,
     assetType: 'preview',
@@ -718,6 +746,138 @@ const DetailPanel = ({
     [bulkCorrespondents, onBulkCorrespondentRemove, onCorrespondentRemove, selectedDocuments],
   );
 
+  const openZoomPreview = useCallback((config) => {
+    if (!config) return;
+    setZoomedPreview({
+      mode: config.mode,
+      docId: config.docId ?? null,
+    });
+  }, []);
+
+  const closeZoomPreview = useCallback(() => {
+    setZoomedPreview(null);
+  }, []);
+
+  const handleSingleZoom = useCallback(
+    (entry) => {
+      if (!singleHasPreview) return;
+      const targetId = entry?.id ?? singleDocId;
+      if (!targetId) return;
+      openZoomPreview({ mode: 'single', docId: targetId });
+    },
+    [openZoomPreview, singleHasPreview, singleDocId],
+  );
+
+  const handleStackZoom = useCallback(
+    (entry) => {
+      if (!stackTopDocId || entry?.id !== stackTopDocId) return;
+      if (!topHasPreview) return;
+      openZoomPreview({ mode: 'stack', docId: stackTopDocId });
+    },
+    [openZoomPreview, stackTopDocId, topHasPreview],
+  );
+
+  const zoomDisplay = useMemo(() => {
+    if (!zoomedPreview) {
+      return null;
+    }
+
+    if (
+      zoomedPreview.mode === 'single' &&
+      singleDocId &&
+      singleDoc &&
+      singleHasPreview &&
+      zoomedPreview.docId === singleDocId
+    ) {
+      return {
+        url: singlePreviewNavigator.currentUrl,
+        alt: singleDoc.title || singleDoc.original_name || 'Document preview',
+        canGoPrev:
+          singleEffectiveCardinality > 1 && Boolean(singlePreviewNavigator.canGoPrev),
+        canGoNext:
+          singleEffectiveCardinality > 1 && Boolean(singlePreviewNavigator.canGoNext),
+        goPrev: singlePreviewNavigator.goPrev,
+        goNext: singlePreviewNavigator.goNext,
+      };
+    }
+
+    if (
+      zoomedPreview.mode === 'stack' &&
+      stackTopDocId &&
+      stackTopDocument &&
+      zoomedPreview.docId === stackTopDocId &&
+      topHasPreview
+    ) {
+      return {
+        url: stackPreviewNavigator.currentUrl,
+        alt: stackTopDocument.title || stackTopDocument.original_name || 'Document preview',
+        canGoPrev:
+          topEffectiveCardinality > 1 && Boolean(stackPreviewNavigator.canGoPrev),
+        canGoNext:
+          topEffectiveCardinality > 1 && Boolean(stackPreviewNavigator.canGoNext),
+        goPrev: stackPreviewNavigator.goPrev,
+        goNext: stackPreviewNavigator.goNext,
+      };
+    }
+
+    return null;
+  }, [
+    zoomedPreview,
+    singleDoc,
+    singleDocId,
+    singleHasPreview,
+    singlePreviewNavigator.currentUrl,
+    singlePreviewNavigator.canGoPrev,
+    singlePreviewNavigator.canGoNext,
+    singlePreviewNavigator.goPrev,
+    singlePreviewNavigator.goNext,
+    singleEffectiveCardinality,
+    stackTopDocument,
+    stackTopDocId,
+    topHasPreview,
+    stackPreviewNavigator.currentUrl,
+    stackPreviewNavigator.canGoPrev,
+    stackPreviewNavigator.canGoNext,
+    stackPreviewNavigator.goPrev,
+    stackPreviewNavigator.goNext,
+    topEffectiveCardinality,
+  ]);
+
+  useEffect(() => {
+    if (zoomedPreview && !zoomDisplay) {
+      setZoomedPreview(null);
+    }
+  }, [zoomedPreview, zoomDisplay]);
+
+  useEffect(() => {
+    if (!zoomedPreview) {
+      return undefined;
+    }
+    const handleKeyDown = (event) => {
+      if (event.key === 'Escape') {
+        setZoomedPreview(null);
+        return;
+      }
+      if (event.key === 'ArrowLeft') {
+        event.preventDefault();
+        event.stopPropagation();
+        if (zoomDisplay?.canGoPrev) {
+          zoomDisplay.goPrev?.();
+        }
+        return;
+      }
+      if (event.key === 'ArrowRight') {
+        event.preventDefault();
+        event.stopPropagation();
+        if (zoomDisplay?.canGoNext) {
+          zoomDisplay.goNext?.();
+        }
+      }
+    };
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [zoomedPreview, zoomDisplay]);
+
   const renderSingle = () => {
     if (!singleDoc) {
       return <p className="meta">Select a document to view metadata, tags and actions.</p>;
@@ -759,6 +919,7 @@ const DetailPanel = ({
             emptyMessage="Preview loading…"
             onItemActivate={handlePreviewActivate}
             onOpenPreview={onOpenPreview}
+            onZoomPreview={handleSingleZoom}
             activeItemId={activePreviewId}
           />
           {hasPreviewImage && (effectiveCardinality > 1 || canGoPrev || canGoNext) ? (
@@ -980,6 +1141,7 @@ const DetailPanel = ({
             emptyMessage="No previews available."
             onItemActivate={handlePreviewActivate}
             onOpenPreview={onOpenPreview}
+            onZoomPreview={handleStackZoom}
             activeItemId={activePreviewId}
           />
           {topDocIdLocal && topHasPreview && (topCardinalityLocal > 1 || topCanGoPrev || topCanGoNext) ? (
@@ -1060,13 +1222,14 @@ const DetailPanel = ({
   const showOcrAction = Boolean(singleDoc && hasOcrAsset);
 
   return (
-    <aside className="detail-panel panel">
-      <div className="panel-header">
-        <div className="panel-actions">
-          <button
-            type="button"
-            className="icon-button ghost"
-            onClick={onClose}
+    <>
+      <aside className="detail-panel panel">
+        <div className="panel-header">
+          <div className="panel-actions">
+            <button
+              type="button"
+              className="icon-button ghost"
+              onClick={onClose}
             aria-label="Close detail panel"
             title="Close detail panel"
           >
@@ -1148,7 +1311,62 @@ const DetailPanel = ({
       <div className="panel-body">
         {selectedCount <= 1 ? renderSingle() : renderBulk()}
       </div>
-    </aside>
+      </aside>
+      {zoomDisplay?.url
+        ? createPortal(
+            <div
+              className="preview-zoom-backdrop"
+              role="dialog"
+              aria-modal="true"
+              aria-label="Enlarged document preview"
+              onClick={closeZoomPreview}
+            >
+              <div className="preview-zoom__stage" onClick={(event) => event.stopPropagation()}>
+                <img
+                  src={zoomDisplay.url}
+                  alt={zoomDisplay.alt}
+                  className="preview-zoom__image"
+                  onClick={(event) => {
+                    event.stopPropagation();
+                    closeZoomPreview();
+                  }}
+                />
+                <div className="preview-zoom__nav">
+                  <button
+                    type="button"
+                    className="preview-zoom__nav-button"
+                    onClick={(event) => {
+                      event.stopPropagation();
+                      if (zoomDisplay.canGoPrev) {
+                        zoomDisplay.goPrev?.();
+                      }
+                    }}
+                    aria-label="Previous preview"
+                    disabled={!zoomDisplay.canGoPrev}
+                  >
+                    <ArrowLeftIcon />
+                  </button>
+                  <button
+                    type="button"
+                    className="preview-zoom__nav-button"
+                    onClick={(event) => {
+                      event.stopPropagation();
+                      if (zoomDisplay.canGoNext) {
+                        zoomDisplay.goNext?.();
+                      }
+                    }}
+                    aria-label="Next preview"
+                    disabled={!zoomDisplay.canGoNext}
+                  >
+                    <ArrowRightIcon />
+                  </button>
+                </div>
+              </div>
+            </div>,
+            document.body,
+          )
+        : null}
+    </>
   );
 };
 
diff --git a/frontend/src/styles.css b/frontend/src/styles.css
index acacaed..9fde27c 100644
--- a/frontend/src/styles.css
+++ b/frontend/src/styles.css
@@ -215,6 +215,92 @@ button.danger:hover:not([disabled]) {
   background: var(--sidebar-hover-bg);
 }
 
+.preview-zoom-backdrop {
+  position: fixed;
+  inset: 0;
+  background: var(--overlay-backdrop);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 2rem;
+  z-index: 3000;
+  cursor: zoom-out;
+}
+
+.preview-zoom__stage {
+  position: relative;
+  display: inline-flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 1.25rem;
+  max-width: 95vw;
+  max-height: 95vh;
+}
+
+.preview-zoom__image {
+  max-width: 95vw;
+  max-height: 95vh;
+  width: auto;
+  height: auto;
+  border-radius: 0;
+  box-shadow: 0 32px 120px rgba(15, 23, 42, 0.55);
+  cursor: inherit;
+}
+
+.preview-zoom__nav {
+  position: absolute;
+  bottom: 1em;
+  left: 50%;
+  transform: translateX(-50%);
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 0.9rem;
+  opacity: 0;
+  transition: opacity 0.18s ease;
+}
+
+.preview-zoom__stage:hover .preview-zoom__nav,
+.preview-zoom__stage:focus-within .preview-zoom__nav {
+  opacity: 1;
+}
+
+.preview-zoom__nav-button {
+  width: 2.8rem;
+  height: 2.8rem;
+  border: none;
+  border-radius: 999px;
+  background: rgba(0, 0, 0, 0.62);
+  color: #fff;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  cursor: pointer;
+  z-index: 1;
+  transition: background 0.15s ease, transform 0.15s ease;
+  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.28);
+}
+
+.preview-zoom__nav-button:hover {
+  background: rgba(0, 0, 0, 0.82);
+}
+
+.preview-zoom__nav-button:focus-visible {
+  outline: 2px solid var(--accent, #4f46e5);
+  outline-offset: 3px;
+}
+
+.preview-zoom__nav-button svg {
+  width: 1.5rem;
+  height: 1.5rem;
+}
+
+.preview-zoom__nav-button[disabled] {
+  opacity: 0.35;
+  cursor: default;
+}
+
 .with-icon {
   display: inline-flex;
   align-items: center;