diff --git a/src/DiagramEditor.tsx b/src/DiagramEditor.tsx
index 336822c..ac92f4f 100644
--- a/src/DiagramEditor.tsx
+++ b/src/DiagramEditor.tsx
@@ -12,10 +12,12 @@ import {
   ViewportPortal,
   useReactFlow,
   addEdge,
+  reconnectEdge,
   applyNodeChanges,
   applyEdgeChanges,
   type Node,
   type Edge,
+  type Connection,
   type OnConnect,
   type NodeChange,
   type EdgeChange,
@@ -132,6 +134,7 @@ function toRfNodes(doc: DiagramDocument | null): Node[] {
       data: node.data,
       width: node.width ?? defaults.width,
       height: node.height ?? defaults.height,
+      zIndex: node.zIndex,
       ...(node.parentId ? { parentId: node.parentId } : {}),
     };
   });
@@ -147,6 +150,7 @@ function toRfEdges(doc: DiagramDocument | null): Edge[] {
     type: edge.type ?? DEFAULT_EDGE_TYPE,
     markerEnd: DEFAULT_MARKER_END,
     label: edge.label,
+    zIndex: edge.zIndex,
     data: edge.data,
   }));
 }
@@ -330,6 +334,17 @@ function DiagramCanvas({ initialValue, onChange }: DiagramEditorProps) {
     [nodes, edges, emitChange, pushHistory],
   );
 
+  const onReconnect = useCallback(
+    (oldEdge: Edge, connection: Connection) => {
+      pushHistory(nodes, edges);
+      // Keep the original edge id stable so selection/history don't go stale mid-drag.
+      const next = reconnectEdge(oldEdge, connection, edges, { shouldReplaceId: false });
+      setEdges(next);
+      emitChange(nodes, next);
+    },
+    [nodes, edges, emitChange, pushHistory],
+  );
+
   const onNodeClick: NodeMouseHandler = useCallback((_event, node) => {
     setSelectedNodeId(node.id);
     setSelectedEdgeId(null);
@@ -462,6 +477,53 @@ function DiagramCanvas({ initialValue, onChange }: DiagramEditorProps) {
     setSelectedEdgeId(null);
   }, [selectedEdgeId, nodes, edges, emitChange, pushHistory]);
 
+  // Nodes and edges share one z-index space (zIndexMode="manual"), so front/back
+  // always means "above/below everything currently on the canvas", not just siblings.
+  const maxZIndex = useCallback(
+    () => Math.max(0, ...nodes.map((n) => n.zIndex ?? 0), ...edges.map((e) => e.zIndex ?? 0)),
+    [nodes, edges],
+  );
+  const minZIndex = useCallback(
+    () => Math.min(0, ...nodes.map((n) => n.zIndex ?? 0), ...edges.map((e) => e.zIndex ?? 0)),
+    [nodes, edges],
+  );
+
+  const bringSelectedNodeToFront = useCallback(() => {
+    if (!selectedNodeId) return;
+    const z = maxZIndex() + 1;
+    pushHistory(nodes, edges);
+    const next = nodes.map((n) => (n.id === selectedNodeId ? { ...n, zIndex: z } : n));
+    setNodes(next);
+    emitChange(next, edges);
+  }, [selectedNodeId, nodes, edges, emitChange, pushHistory, maxZIndex]);
+
+  const sendSelectedNodeToBack = useCallback(() => {
+    if (!selectedNodeId) return;
+    const z = minZIndex() - 1;
+    pushHistory(nodes, edges);
+    const next = nodes.map((n) => (n.id === selectedNodeId ? { ...n, zIndex: z } : n));
+    setNodes(next);
+    emitChange(next, edges);
+  }, [selectedNodeId, nodes, edges, emitChange, pushHistory, minZIndex]);
+
+  const bringSelectedEdgeToFront = useCallback(() => {
+    if (!selectedEdgeId) return;
+    const z = maxZIndex() + 1;
+    pushHistory(nodes, edges);
+    const next = edges.map((e) => (e.id === selectedEdgeId ? { ...e, zIndex: z } : e));
+    setEdges(next);
+    emitChange(nodes, next);
+  }, [selectedEdgeId, nodes, edges, emitChange, pushHistory, maxZIndex]);
+
+  const sendSelectedEdgeToBack = useCallback(() => {
+    if (!selectedEdgeId) return;
+    const z = minZIndex() - 1;
+    pushHistory(nodes, edges);
+    const next = edges.map((e) => (e.id === selectedEdgeId ? { ...e, zIndex: z } : e));
+    setEdges(next);
+    emitChange(nodes, next);
+  }, [selectedEdgeId, nodes, edges, emitChange, pushHistory, minZIndex]);
+
   useEffect(() => {
     function onKeyDown(event: KeyboardEvent) {
       if (mode !== 'edit' || isEditableTarget(event.target)) return;
@@ -500,6 +562,8 @@ function DiagramCanvas({ initialValue, onChange }: DiagramEditorProps) {
             onNodesChange={onNodesChange}
             onEdgesChange={onEdgesChange}
             onConnect={onConnect}
+            onReconnect={onReconnect}
+            edgesReconnectable={mode === 'edit'}
             onNodeClick={onNodeClick}
             onEdgeClick={onEdgeClick}
             onPaneClick={onPaneClick}
@@ -508,6 +572,7 @@ function DiagramCanvas({ initialValue, onChange }: DiagramEditorProps) {
             deleteKeyCode={mode === 'edit' ? undefined : null}
             zoomOnDoubleClick={false}
             connectionMode={ConnectionMode.Loose}
+            zIndexMode="manual"
             className={mode === 'view' ? 'diagram-flow--view-mode' : undefined}
             fitView
           >
@@ -589,6 +654,8 @@ function DiagramCanvas({ initialValue, onChange }: DiagramEditorProps) {
             onEnterSubProcess={enterSubProcess}
             onDuplicate={duplicateSelectedNode}
             onDelete={deleteSelectedNode}
+            onBringToFront={bringSelectedNodeToFront}
+            onSendToBack={sendSelectedNodeToBack}
           />
         ) : selectedEdge ? (
           <EdgeInspector
@@ -596,6 +663,8 @@ function DiagramCanvas({ initialValue, onChange }: DiagramEditorProps) {
             label={typeof selectedEdge.label === 'string' ? selectedEdge.label : ''}
             onChange={updateSelectedEdgeLabel}
             onDelete={deleteSelectedEdge}
+            onBringToFront={bringSelectedEdgeToFront}
+            onSendToBack={sendSelectedEdgeToBack}
           />
         ) : (
           <p className="diagram-aside__hint">
diff --git a/src/EdgeInspector.tsx b/src/EdgeInspector.tsx
index 0f81ca4..c9f0ec3 100644
--- a/src/EdgeInspector.tsx
+++ b/src/EdgeInspector.tsx
@@ -3,9 +3,18 @@ interface EdgeInspectorProps {
   label: string;
   onChange: (label: string) => void;
   onDelete: () => void;
+  onBringToFront: () => void;
+  onSendToBack: () => void;
 }
 
-export function EdgeInspector({ edgeId, label, onChange, onDelete }: EdgeInspectorProps) {
+export function EdgeInspector({
+  edgeId,
+  label,
+  onChange,
+  onDelete,
+  onBringToFront,
+  onSendToBack,
+}: EdgeInspectorProps) {
   return (
     <div className="node-inspector">
       <div className="node-inspector__header">
@@ -19,6 +28,15 @@ export function EdgeInspector({ edgeId, label, onChange, onDelete }: EdgeInspect
         </button>
       </div>
 
+      <div className="node-inspector__toolbar">
+        <button type="button" onClick={onBringToFront}>
+          На передний план
+        </button>
+        <button type="button" onClick={onSendToBack}>
+          На задний план
+        </button>
+      </div>
+
       <label className="node-inspector__field">
         Подпись
         <input type="text" value={label} onChange={(e) => onChange(e.target.value)} />
diff --git a/src/NodeInspector.tsx b/src/NodeInspector.tsx
index 6a1341d..be47d84 100644
--- a/src/NodeInspector.tsx
+++ b/src/NodeInspector.tsx
@@ -21,6 +21,8 @@ interface NodeInspectorProps {
   onEnterSubProcess: (nodeId: string) => void;
   onDuplicate: () => void;
   onDelete: () => void;
+  onBringToFront: () => void;
+  onSendToBack: () => void;
 }
 
 export function NodeInspector({
@@ -33,6 +35,8 @@ export function NodeInspector({
   onEnterSubProcess,
   onDuplicate,
   onDelete,
+  onBringToFront,
+  onSendToBack,
 }: NodeInspectorProps) {
   if (mode === 'view') {
     const hasMeta = Boolean(data.responsible || data.duration);
@@ -88,6 +92,15 @@ export function NodeInspector({
         </button>
       </div>
 
+      <div className="node-inspector__toolbar">
+        <button type="button" onClick={onBringToFront}>
+          На передний план
+        </button>
+        <button type="button" onClick={onSendToBack}>
+          На задний план
+        </button>
+      </div>
+
       <label className="node-inspector__field node-inspector__field--color">
         Цвет фона
         <input
diff --git a/src/diagram.css b/src/diagram.css
index be786b1..e451b70 100644
--- a/src/diagram.css
+++ b/src/diagram.css
@@ -181,26 +181,23 @@
   position: relative;
   width: 100%;
   height: 100%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
-/*
- * Inset to 1/sqrt(2) of the outer box and rotated 45deg: the diamond's tips
- * exactly reach the outer box's edges without the corners clipping outside it.
- */
-.diagram-node--diamond {
+/* Diamond via clip-path on an unrotated box — see the comment in nodes.tsx for why. */
+.diagram-node--diamond-bg {
   position: absolute;
-  top: 50%;
-  left: 50%;
-  width: 70.71%;
-  height: 70.71%;
-  padding: 0;
-  border-radius: 4px;
-  transform: translate(-50%, -50%) rotate(45deg);
+  inset: 0;
+  border: 1px solid #555;
+  box-sizing: border-box;
+  clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
 }
 
 .diagram-node__icon {
+  position: relative;
   display: inline-block;
-  transform: rotate(-45deg);
   font-size: 18px;
   font-weight: 700;
   line-height: 1;
diff --git a/src/nodes.tsx b/src/nodes.tsx
index 7145b5c..bb2d5c7 100644
--- a/src/nodes.tsx
+++ b/src/nodes.tsx
@@ -1,4 +1,4 @@
-import { createContext, useContext, type CSSProperties } from 'react';
+import { createContext, useContext } from 'react';
 import { Handle, NodeResizer, Position, type Node, type NodeProps } from '@xyflow/react';
 import type { DiagramNodeData, NodeKind } from './types';
 
@@ -42,33 +42,6 @@ function ShapeHandles() {
   );
 }
 
-/**
- * The diamond div is a rotated square (`transform: rotate(45deg)`). Handles
- * placed at the square's own corners land on the diamond's tips once rotated
- * — corners, not `Position.Top/Right/Bottom/Left` (those are edge-midpoints,
- * which rotate onto the diamond's flat sides instead).
- */
-const DIAMOND_HANDLES: { id: string; position: Position; style: CSSProperties }[] = [
-  { id: 'top', position: Position.Top, style: { top: 0, left: 0, transform: 'translate(-50%, -50%)' } },
-  { id: 'right', position: Position.Right, style: { top: 0, left: '100%', transform: 'translate(-50%, -50%)' } },
-  {
-    id: 'bottom',
-    position: Position.Bottom,
-    style: { top: '100%', left: '100%', transform: 'translate(-50%, -50%)' },
-  },
-  { id: 'left', position: Position.Left, style: { top: '100%', left: 0, transform: 'translate(-50%, -50%)' } },
-];
-
-function DiamondHandles() {
-  return (
-    <>
-      {DIAMOND_HANDLES.map(({ id, position, style }) => (
-        <Handle key={id} id={id} type="source" position={position} style={style} />
-      ))}
-    </>
-  );
-}
-
 function SubProcessBadge({ id }: { id: string }) {
   const withChildren = useContext(NodesWithChildrenContext);
   if (!withChildren.has(id)) return null;
@@ -145,19 +118,22 @@ function GatewayNode({ id, data, type, selected }: NodeProps<ShapeNode>) {
     <div className="diagram-node--gateway-outer">
       <ShapeResizer selected={selected} minWidth={32} minHeight={32} />
       {/*
-        The diamond is an inner square inset to 1/sqrt(2) of the outer box and
-        rotated 45deg, so its tips exactly reach the outer box's edges without
-        clipping. The caption sits on the (unrotated) outer box instead of the
-        diamond itself, so it renders upright below the shape.
+        The diamond is drawn with clip-path on a plain (unrotated) box, not
+        `transform: rotate(45deg)` — a rotated element makes React Flow's
+        getBoundingClientRect-based handle measurement pick up sub-pixel
+        rounding from the rotation, which showed up as a visible kink in
+        otherwise-straight horizontal/vertical edges. With clip-path, the
+        standard Position.Top/Right/Bottom/Left handles already land exactly
+        on the diamond's tips (they're at the box's edge midpoints either
+        way), so this reuses the same ShapeHandles as every other shape.
+        Handles/badge/caption are siblings of the clipped div, not children
+        of it, since clip-path would otherwise cut off anything of theirs
+        that renders outside the diamond outline.
       */}
-      <div
-        className="diagram-node diagram-node--diamond"
-        style={{ background: data.color ?? DEFAULT_NODE_COLOR[kind] }}
-      >
-        <DiamondHandles />
-        <span className="diagram-node__icon">{GATEWAY_ICON[kind]}</span>
-      </div>
+      <div className="diagram-node--diamond-bg" style={{ background: data.color ?? DEFAULT_NODE_COLOR[kind] }} />
+      <ShapeHandles />
       <SubProcessBadge id={id} />
+      <span className="diagram-node__icon">{GATEWAY_ICON[kind]}</span>
       <span className="diagram-node__caption">{data.label}</span>
     </div>
   );
diff --git a/src/serialize.ts b/src/serialize.ts
index 9d232ef..eb3c2e2 100644
--- a/src/serialize.ts
+++ b/src/serialize.ts
@@ -3,7 +3,7 @@ import type { DiagramDocument, DiagramEdge, DiagramNode, NodeKind } from './type
 
 /**
  * React Flow's runtime Node/Edge carry UI-only fields (measured, selected,
- * dragging, zIndex, ...). Only this subset gets persisted.
+ * dragging, ...). Only this subset gets persisted.
  */
 export function serializeDocument(nodes: Node[], edges: Edge[]): DiagramDocument {
   return {
@@ -16,6 +16,7 @@ export function serializeDocument(nodes: Node[], edges: Edge[]): DiagramDocument
         ...(node.parentId ? { parentId: node.parentId } : {}),
         ...(typeof node.width === 'number' ? { width: node.width } : {}),
         ...(typeof node.height === 'number' ? { height: node.height } : {}),
+        ...(typeof node.zIndex === 'number' ? { zIndex: node.zIndex } : {}),
       }),
     ),
     edges: edges.map(
@@ -27,6 +28,7 @@ export function serializeDocument(nodes: Node[], edges: Edge[]): DiagramDocument
         ...(edge.targetHandle ? { targetHandle: edge.targetHandle } : {}),
         type: edge.type,
         ...(typeof edge.label === 'string' && edge.label ? { label: edge.label } : {}),
+        ...(typeof edge.zIndex === 'number' ? { zIndex: edge.zIndex } : {}),
         data: edge.data as DiagramEdge['data'],
       }),
     ),
diff --git a/src/types.ts b/src/types.ts
index 5a162f3..8270c47 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -24,6 +24,8 @@ export interface DiagramNode {
   parentId?: string;
   width?: number;
   height?: number;
+  /** Manual stacking order — shared z-space with edges, higher draws on top. */
+  zIndex?: number;
 }
 
 export interface DiagramEdgeData extends Record<string, unknown> {}
@@ -38,6 +40,8 @@ export interface DiagramEdge {
   type?: string;
   label?: string;
   data?: DiagramEdgeData;
+  /** Manual stacking order — shared z-space with nodes, higher draws on top. */
+  zIndex?: number;
 }
 
 export interface DiagramDocument {