frontend/src/features/workspace/DocumentEditor.tsx

@@ -11,6 +11,11 @@ import {
   ArrowLeft,
   Hash,
   Lock,
+  Home,
+  ChevronRight,
+  Minimize2,
+  Sparkles,
+  Plus,
 } from 'lucide-react';
 import { Document, DocumentBlock, User } from '../../lib/types';
 import { api } from '../../lib/api';
@@ -55,6 +60,85 @@ function ensureNonEmptyBlocks(docId: string, blocks?: DocumentBlock[]): Document
   }));
 }
 
+export interface BreadcrumbNode {
+  id: string | null;
+  title: string;
+}
+
+export function computeBreadcrumbs(
+  docTitle: string,
+  blocks: DocumentBlock[],
+  zoomedBlockId: string | null
+): BreadcrumbNode[] {
+  if (!zoomedBlockId) return [];
+
+  const zoomedIdx = blocks.findIndex((b) => b.id === zoomedBlockId);
+  if (zoomedIdx === -1) return [];
+
+  const trail: BreadcrumbNode[] = [];
+  const zoomedBlock = blocks[zoomedIdx];
+
+  let currentLevel = zoomedBlock.level;
+  for (let i = zoomedIdx - 1; i >= 0; i--) {
+    if (blocks[i].level < currentLevel) {
+      trail.unshift({
+        id: blocks[i].id,
+        title: blocks[i].content?.trim() || 'Punkt',
+      });
+      currentLevel = blocks[i].level;
+      if (currentLevel === 0) break;
+    }
+  }
+
+  trail.unshift({
+    id: null,
+    title: docTitle || 'Dokument',
+  });
+
+  trail.push({
+    id: zoomedBlock.id,
+    title: zoomedBlock.content?.trim() || 'Punkt',
+  });
+
+  return trail;
+}
+
+export function getZoomedSubtree(
+  blocks: DocumentBlock[],
+  zoomedBlockId: string | null
+): {
+  zoomedBlock: DocumentBlock | null;
+  childBlocks: DocumentBlock[];
+  levelOffset: number;
+} {
+  if (!zoomedBlockId) {
+    return { zoomedBlock: null, childBlocks: blocks, levelOffset: 0 };
+  }
+
+  const idx = blocks.findIndex((b) => b.id === zoomedBlockId);
+  if (idx === -1) {
+    return { zoomedBlock: null, childBlocks: blocks, levelOffset: 0 };
+  }
+
+  const zoomedBlock = blocks[idx];
+  const zLevel = zoomedBlock.level;
+  const childBlocks: DocumentBlock[] = [];
+
+  for (let i = idx + 1; i < blocks.length; i++) {
+    if (blocks[i].level > zLevel) {
+      childBlocks.push(blocks[i]);
+    } else {
+      break;
+    }
+  }
+
+  return {
+    zoomedBlock,
+    childBlocks,
+    levelOffset: zLevel + 1,
+  };
+}
+
 export const DocumentEditor: React.FC<DocumentEditorProps> = ({
   docId,
   currentUser,
@@ -76,6 +160,21 @@ export const DocumentEditor: React.FC<DocumentEditorProps> = ({
   const [error, setError] = useState<string | null>(null);
   const [showEmojiPicker, setShowEmojiPicker] = useState<boolean>(false);
   const [showFolderMenu, setShowFolderMenu] = useState<boolean>(false);
+  const [zoomedBlockId, setZoomedBlockId] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (zoomedBlockId && !blocks.some((b) => b.id === zoomedBlockId)) {
+      setZoomedBlockId(null);
+    }
+  }, [blocks, zoomedBlockId]);
+
+  const { zoomedBlock, childBlocks, levelOffset } = useMemo(() => {
+    return getZoomedSubtree(blocks, zoomedBlockId);
+  }, [blocks, zoomedBlockId]);
+
+  const breadcrumbs = useMemo(() => {
+    return computeBreadcrumbs(title || doc?.title || 'Dokument', blocks, zoomedBlockId);
+  }, [title, doc?.title, blocks, zoomedBlockId]);
 
   const titleInputRef = useRef<HTMLInputElement | null>(null);
   const titleDebounceRef = useRef<number | null>(null);
@@ -640,75 +739,227 @@ export const DocumentEditor: React.FC<DocumentEditorProps> = ({
 
       {/* Main Content Area */}
       <div className="max-w-4xl w-full mx-auto px-4 sm:px-8 py-5 flex-1">
-        {/* Document Icon + Title Header */}
-        <div className="flex items-center gap-3 mb-3 relative">
-          <div className="relative">
-            <button
-              type="button"
-              onClick={() => canEdit && setShowEmojiPicker((prev) => !prev)}
-              className="w-10 h-10 rounded-btn bg-panel-elevated border border-border hover:border-strong flex items-center justify-center text-xl transition-colors"
-              title="Icon ändern"
-            >
-              {doc?.icon || '📝'}
-            </button>
-            {showEmojiPicker && canEdit && (
-              <div className="absolute left-0 mt-1 p-2 panel-surface shadow-panel border border-border rounded-card grid grid-cols-6 gap-1 z-30 w-52">
-                {EMOJI_PALETTE.map((emoji) => (
+        {zoomedBlock ? (
+          /* =========================================================================
+             FOKUS-MODUS & ZOOM-IN (HOISTED SUBTREE VIEW)
+             ========================================================================= */
+          <div className="space-y-3">
+            {/* Clickable Breadcrumb Bar */}
+            {breadcrumbs.length > 0 && (
+              <nav
+                aria-label="Breadcrumb Navigation"
+                className="flex items-center flex-wrap gap-1.5 py-1.5 px-3 bg-panel-elevated/70 border border-border rounded-card text-xs text-muted"
+              >
+                <button
+                  type="button"
+                  onClick={() => setZoomedBlockId(null)}
+                  className="hover:text-accent inline-flex items-center gap-1 font-medium transition-colors"
+                  title="Zurück zum Hauptdokument"
+                >
+                  <Home className="w-3.5 h-3.5 text-accent" />
+                  <span className="truncate max-w-[120px]">
+                    {title || doc?.title || 'Dokument'}
+                  </span>
+                </button>
+
+                {breadcrumbs.slice(1).map((crumb, idx) => {
+                  const isCurrent = idx === breadcrumbs.length - 2;
+                  return (
+                    <React.Fragment key={crumb.id || idx}>
+                      <ChevronRight className="w-3 h-3 text-faint shrink-0" />
+                      {isCurrent ? (
+                        <span
+                          className="font-bold text-accent truncate max-w-[200px]"
+                          title={crumb.title}
+                        >
+                          {crumb.title || 'Punkt'}
+                        </span>
+                      ) : (
+                        <button
+                          type="button"
+                          onClick={() => setZoomedBlockId(crumb.id)}
+                          className="hover:text-main truncate max-w-[140px] transition-colors"
+                          title={`Zoom zu "${crumb.title}"`}
+                        >
+                          {crumb.title || 'Punkt'}
+                        </button>
+                      )}
+                    </React.Fragment>
+                  );
+                })}
+              </nav>
+            )}
+
+            {/* Prominent Zoomed Ast-Heading */}
+            <div className="flex items-start justify-between gap-3 pb-4 mb-2 border-b border-border">
+              <div className="flex-1 min-w-0">
+                <div className="flex items-center gap-2 mb-1.5">
+                  <span className="inline-flex items-center gap-1 text-[10px] font-bold uppercase tracking-wider text-accent bg-accent-dim px-2 py-0.5 rounded-btn border border-accent/30">
+                    <Sparkles className="w-2.5 h-2.5 text-accent animate-pulse" />
+                    Fokus-Modus
+                  </span>
+                  <span className="text-[11px] text-faint hidden sm:inline">
+                    Isolierter Ast • Zoom aktiv
+                  </span>
+                </div>
+                <input
+                  type="text"
+                  value={zoomedBlock.content}
+                  onChange={(e) => {
+                    handleUpdateBlock({ ...zoomedBlock, content: e.target.value });
+                  }}
+                  onKeyDown={(e) => {
+                    if (e.key === 'Enter') {
+                      e.preventDefault();
+                      const firstChild: DocumentBlock = {
+                        id: `blk_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 7)}`,
+                        documentId: docId,
+                        type: 'text',
+                        content: '',
+                        level: levelOffset,
+                        position: (zoomedBlock.position || 1000) + 10,
+                      };
+                      handleCreateBlock(firstChild, zoomedBlock.id);
+                    }
+                  }}
+                  placeholder="Ast-Titel…"
+                  readOnly={!canEdit}
+                  className="w-full text-2xl sm:text-3xl font-extrabold text-main bg-transparent border-0 focus:outline-none focus:ring-0 tracking-tight leading-tight"
+                />
+              </div>
+
+              <button
+                type="button"
+                onClick={() => setZoomedBlockId(null)}
+                className="btn-action inline-flex items-center gap-1.5 px-2.5 py-1 text-xs text-muted hover:text-main shrink-0 mt-1"
+                title="Fokus-Modus beenden"
+              >
+                <Minimize2 className="w-3.5 h-3.5" />
+                <span className="hidden sm:inline">Fokus beenden</span>
+              </button>
+            </div>
+
+            {/* Subtree Children or Empty State */}
+            {childBlocks.length === 0 ? (
+              <div className="py-8 text-center text-xs text-faint border border-dashed border-border rounded-card my-2">
+                <p className="mb-2">Dieser Ast hat noch keine Unterpunkte.</p>
+                {canEdit && (
                   <button
-                    key={emoji}
                     type="button"
-                    onClick={() => handleSelectIcon(emoji)}
-                    className="p-1.5 rounded-btn hover:bg-panel-elevated text-base flex items-center justify-center"
+                    onClick={() => {
+                      const firstChild: DocumentBlock = {
+                        id: `blk_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 7)}`,
+                        documentId: docId,
+                        type: 'text',
+                        content: '',
+                        level: levelOffset,
+                        position: (zoomedBlock.position || 1000) + 10,
+                      };
+                      handleCreateBlock(firstChild, zoomedBlock.id);
+                    }}
+                    className="btn-action inline-flex items-center gap-1.5 px-3 py-1.5 text-xs text-accent font-medium hover:bg-accent/10"
                   >
-                    {emoji}
+                    <Plus className="w-3.5 h-3.5" />
+                    <span>Ersten Unterpunkt anlegen (oder Enter drücken)</span>
+                  </button>
+                )}
+              </div>
+            ) : (
+              <OutlinerTree
+                docId={docId}
+                blocks={childBlocks}
+                canEdit={canEdit}
+                levelOffset={levelOffset}
+                onZoomBlock={setZoomedBlockId}
+                remoteCursors={remoteCursors}
+                sendCursorMoved={sendCursorMoved}
+                onUpdateBlock={handleUpdateBlock}
+                onCreateBlock={handleCreateBlock}
+                onDeleteBlock={handleDeleteBlock}
+                onMoveBlock={handleMoveBlock}
+                onTagClick={onSelectTag}
+                onWikiLinkClick={onWikiLinkClick}
+              />
+            )}
+          </div>
+        ) : (
+          /* =========================================================================
+             STANDARD GESAMTDOKUMENT-ANSICHT
+             ========================================================================= */
+          <>
+            {/* Document Icon + Title Header */}
+            <div className="flex items-center gap-3 mb-3 relative">
+              <div className="relative">
+                <button
+                  type="button"
+                  onClick={() => canEdit && setShowEmojiPicker((prev) => !prev)}
+                  className="w-10 h-10 rounded-btn bg-panel-elevated border border-border hover:border-strong flex items-center justify-center text-xl transition-colors"
+                  title="Icon ändern"
+                >
+                  {doc?.icon || '📝'}
+                </button>
+                {showEmojiPicker && canEdit && (
+                  <div className="absolute left-0 mt-1 p-2 panel-surface shadow-panel border border-border rounded-card grid grid-cols-6 gap-1 z-30 w-52">
+                    {EMOJI_PALETTE.map((emoji) => (
+                      <button
+                        key={emoji}
+                        type="button"
+                        onClick={() => handleSelectIcon(emoji)}
+                        className="p-1.5 rounded-btn hover:bg-panel-elevated text-base flex items-center justify-center"
+                      >
+                        {emoji}
+                      </button>
+                    ))}
+                  </div>
+                )}
+              </div>
+
+              <input
+                ref={titleInputRef}
+                type="text"
+                value={title}
+                readOnly={!canEdit}
+                onChange={handleTitleChange}
+                placeholder="Titel der Notiz…"
+                className="flex-1 min-w-0 text-xl sm:text-2xl font-bold text-main bg-transparent border-0 focus:outline-none focus:ring-0 tracking-tight"
+              />
+            </div>
+
+            {/* Extracted #Tags Summary Bar */}
+            {extractedTags.length > 0 && (
+              <div className="flex flex-wrap items-center gap-1.5 mb-4 pb-2 border-b border-border">
+                <Hash className="w-3.5 h-3.5 text-faint mr-0.5" />
+                {extractedTags.map((tag) => (
+                  <button
+                    key={tag}
+                    type="button"
+                    onClick={() => onSelectTag(tag)}
+                    className="badge-accent text-[11px] font-medium px-2 py-0.5 rounded-btn hover:opacity-85 transition-opacity"
+                  >
+                    #{tag}
                   </button>
                 ))}
               </div>
             )}
-          </div>
 
-          <input
-            ref={titleInputRef}
-            type="text"
-            value={title}
-            readOnly={!canEdit}
-            onChange={handleTitleChange}
-            placeholder="Titel der Notiz…"
-            className="flex-1 min-w-0 text-xl sm:text-2xl font-bold text-main bg-transparent border-0 focus:outline-none focus:ring-0 tracking-tight"
-          />
-        </div>
-
-        {/* Extracted #Tags Summary Bar */}
-        {extractedTags.length > 0 && (
-          <div className="flex flex-wrap items-center gap-1.5 mb-4 pb-2 border-b border-border">
-            <Hash className="w-3.5 h-3.5 text-faint mr-0.5" />
-            {extractedTags.map((tag) => (
-              <button
-                key={tag}
-                type="button"
-                onClick={() => onSelectTag(tag)}
-                className="badge-accent text-[11px] font-medium px-2 py-0.5 rounded-btn hover:opacity-85 transition-opacity"
-              >
-                #{tag}
-              </button>
-            ))}
-          </div>
+            {/* Logseq Outliner Tree */}
+            <OutlinerTree
+              docId={docId}
+              blocks={blocks}
+              canEdit={canEdit}
+              levelOffset={0}
+              onZoomBlock={setZoomedBlockId}
+              remoteCursors={remoteCursors}
+              sendCursorMoved={sendCursorMoved}
+              onUpdateBlock={handleUpdateBlock}
+              onCreateBlock={handleCreateBlock}
+              onDeleteBlock={handleDeleteBlock}
+              onMoveBlock={handleMoveBlock}
+              onTagClick={onSelectTag}
+              onWikiLinkClick={onWikiLinkClick}
+            />
+          </>
         )}
-
-        {/* Logseq Outliner Tree */}
-        <OutlinerTree
-          docId={docId}
-          blocks={blocks}
-          canEdit={canEdit}
-          remoteCursors={remoteCursors}
-          sendCursorMoved={sendCursorMoved}
-          onUpdateBlock={handleUpdateBlock}
-          onCreateBlock={handleCreateBlock}
-          onDeleteBlock={handleDeleteBlock}
-          onMoveBlock={handleMoveBlock}
-          onTagClick={onSelectTag}
-          onWikiLinkClick={onWikiLinkClick}
-        />
       </div>
     </div>
   );

frontend/src/features/workspace/OutlinerBlock.tsx

@@ -15,6 +15,7 @@ import {
   MessageSquare,
   Hash,
   ExternalLink,
+  Maximize2,
 } from 'lucide-react';
 import { DocumentBlock, BlockType } from '../../lib/types';
 import { RemoteCursor } from '../../lib/useDocumentSync';
@@ -46,6 +47,8 @@ export interface OutlinerBlockProps {
   canEdit: boolean;
   activeRemoteCursors?: RemoteCursor[];
   sendCursorMoved?: (blockId: string | null, selectionStart?: number, selectionEnd?: number) => void;
+  levelOffset?: number;
+  onZoomBlock?: (blockId: string) => void;
   onFocusBlock: (blockId: string) => void;
   onUpdateBlock: (updated: DocumentBlock, immediate?: boolean) => void;
   onCreateBlockBelow: (afterBlockId: string, currentContent: string) => void;
@@ -69,6 +72,8 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
   canEdit,
   activeRemoteCursors = [],
   sendCursorMoved,
+  levelOffset = 0,
+  onZoomBlock,
   onFocusBlock,
   onUpdateBlock,
   onCreateBlockBelow,
@@ -334,6 +339,7 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
   };
 
   const level = Math.max(0, block.level || 0);
+  const visualLevel = Math.max(0, level - (levelOffset || 0));
 
   // Parse rich tokens (WikiLinks [[Page]] and #Tags)
   const tokens = useMemo(() => {
@@ -355,7 +361,7 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
           : 'hover:bg-panel'
       }`}
       style={{
-        paddingLeft: `${level * 22 + 4}px`,
+        paddingLeft: `${visualLevel * 22 + 4}px`,
         ...(primaryRemoteCursor
           ? { borderLeft: `2px solid ${primaryRemoteCursor.userColor}` }
           : {}),
@@ -379,8 +385,8 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
       )}
 
       {/* Indentation Guide Line */}
-      {level > 0 &&
-        Array.from({ length: level }).map((_, lvlIdx) => (
+      {visualLevel > 0 &&
+        Array.from({ length: visualLevel }).map((_, lvlIdx) => (
           <div
             key={lvlIdx}
             className="pointer-events-none absolute top-0 bottom-0 w-px border-l border-border"
@@ -440,15 +446,9 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
         ) : (
           <button
             type="button"
-            onClick={() => {
-              if (canEdit) {
-                flushDebounce(localContent, {
-                  type: block.type === 'todo' ? 'bullet' : 'todo',
-                });
-              }
-            }}
-            className="w-4 h-4 flex items-center justify-center rounded-btn hover:bg-panel-hover"
-            title="Klick: Zu To-Do / Bullet umschalten"
+            onClick={() => onZoomBlock?.(block.id)}
+            className="w-4 h-4 flex items-center justify-center rounded-btn hover:bg-panel-hover group/bullet transition-transform"
+            title="Klick: In diesen Ast hineinzoomen (Fokus-Modus)"
           >
             <span
               className={`w-1.5 h-1.5 rounded-full transition-all ${
@@ -456,7 +456,7 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
                   ? 'bg-accent ring-2 ring-accent/30'
                   : isFocused
                   ? 'bg-accent scale-125'
-                  : 'bg-faint group-hover:bg-accent'
+                  : 'bg-faint group-hover/bullet:bg-accent group-hover/bullet:scale-125'
               }`}
             />
           </button>
@@ -670,6 +670,16 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
         )}
       </div>
 
+      {/* Zoom / Focus button on hover */}
+      <button
+        type="button"
+        onClick={() => onZoomBlock?.(block.id)}
+        className="opacity-0 group-hover:opacity-100 focus:opacity-100 p-0.5 text-faint hover:text-accent rounded-btn transition-opacity shrink-0"
+        title="In diesen Ast hineinzoomen (Fokus-Modus)"
+      >
+        <Maximize2 className="w-3.5 h-3.5" />
+      </button>
+
       {/* Delete button on hover */}
       {canEdit && (
         <button

frontend/src/features/workspace/OutlinerTree.tsx

@@ -8,6 +8,8 @@ export interface OutlinerTreeProps {
   docId: string;
   blocks: DocumentBlock[];
   canEdit: boolean;
+  levelOffset?: number;
+  onZoomBlock?: (blockId: string) => void;
   remoteCursors?: Record<string, RemoteCursor>;
   sendCursorMoved?: (blockId: string | null, selectionStart?: number, selectionEnd?: number) => void;
   onUpdateBlock: (updated: DocumentBlock, immediate?: boolean) => void;
@@ -22,6 +24,8 @@ export const OutlinerTree: React.FC<OutlinerTreeProps> = ({
   docId,
   blocks,
   canEdit,
+  levelOffset = 0,
+  onZoomBlock,
   remoteCursors,
   sendCursorMoved,
   onUpdateBlock,
@@ -105,7 +109,7 @@ export const OutlinerTree: React.FC<OutlinerTreeProps> = ({
       const hasChildren = Boolean(nextBlock && nextLvl > lvl);
 
       const prevBlock = i > 0 ? blocks[i - 1] : null;
-      const maxAllowedLevel = prevBlock ? Math.max(0, prevBlock.level || 0) + 1 : 0;
+      const maxAllowedLevel = prevBlock ? Math.max(0, prevBlock.level || 0) + 1 : (levelOffset || 0);
 
       result.push({
         block: b,
@@ -155,8 +159,8 @@ export const OutlinerTree: React.FC<OutlinerTreeProps> = ({
       const idx = blocks.findIndex((b) => b.id === blockId);
       if (idx === -1) return;
 
-      // If this is the only block in the document, clear its content/type instead of leaving 0 blocks
-      if (blocks.length <= 1) {
+      // If this is the only block in the document (and not in an isolated zoom subtree), clear instead of deleting
+      if (blocks.length <= 1 && !levelOffset) {
         const only = blocks[0];
         onUpdateBlock(
           {
@@ -191,10 +195,11 @@ export const OutlinerTree: React.FC<OutlinerTreeProps> = ({
       const prevLevel = idx > 0 ? Math.max(0, blocks[idx - 1].level || 0) : 0;
       const maxLevel = idx === 0 ? 0 : prevLevel + 1;
 
+      const minLevel = levelOffset || 0;
       const nextLevel =
         delta === 1
           ? Math.min(maxLevel, currentLevel + 1)
-          : Math.max(0, currentLevel - 1);
+          : Math.max(minLevel, currentLevel - 1);
 
       if (nextLevel === currentLevel) return;
 
@@ -283,6 +288,8 @@ export const OutlinerTree: React.FC<OutlinerTreeProps> = ({
           hasChildren={hasChildren}
           isFocused={focusedBlockId === block.id}
           canEdit={canEdit}
+          levelOffset={levelOffset}
+          onZoomBlock={onZoomBlock}
           activeRemoteCursors={cursorsByBlock[block.id] || []}
           sendCursorMoved={sendCursorMoved}
           onFocusBlock={setFocusedBlockId}
@@ -315,7 +322,7 @@ export const OutlinerTree: React.FC<OutlinerTreeProps> = ({
                   documentId: docId,
                   type: 'text',
                   content: '',
-                  level: 0,
+                  level: levelOffset || 0,
                   position: 1000,
                 };
                 pendingFocusRef.current = { blockId: firstBlock.id, cursor: 'start' };