fix: AI Assist panel sits below topbar with slide-in animation

- Panel now uses top:56px to sit below the app shell topbar instead of
  covering it (matches the main-content grid cell area)
- Added slideInRight CSS animation for smooth drawer entrance
- Editor pages use dynamic paddingRight via PANEL_WIDTH constant
- ChatTab upgraded: markdown rendering, CopilotPanel-style message
  bubbles, auto-focus input, Shift+Enter hint
- All borders use --glass-border for consistent glassmorphism

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/editor-ai/ChatTab.tsx

@@ -1,5 +1,6 @@
 import { useRef, useEffect } from 'react'
-import { Send, Sparkles } from 'lucide-react'
+import { Send, Sparkles, Loader2 } from 'lucide-react'
+import { MarkdownContent } from '@/components/ui/MarkdownContent'
 import type { EditorAIChatMessage } from '@/types'
 
 interface ChatTabProps {
@@ -12,11 +13,17 @@ interface ChatTabProps {
 
 export function ChatTab({ messages, input, onInputChange, onSend, isLoading }: ChatTabProps) {
   const messagesEndRef = useRef<HTMLDivElement>(null)
+  const inputRef = useRef<HTMLTextAreaElement>(null)
 
   useEffect(() => {
     messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' })
   }, [messages])
 
+  // Focus input when panel mounts
+  useEffect(() => {
+    requestAnimationFrame(() => inputRef.current?.focus())
+  }, [])
+
   const handleKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
     if (e.key === 'Enter' && !e.shiftKey) {
       e.preventDefault()
@@ -26,7 +33,8 @@ export function ChatTab({ messages, input, onInputChange, onSend, isLoading }: C
 
   return (
     <div className="flex flex-1 flex-col overflow-hidden">
-      <div className="flex-1 overflow-y-auto px-3 py-3 space-y-3">
+      {/* Messages */}
+      <div className="flex-1 overflow-y-auto px-4 py-3 space-y-3">
         {messages.length === 0 && (
           <div className="flex flex-col items-center justify-center h-full text-muted-foreground text-sm">
             <Sparkles className="h-8 w-8 mb-2 opacity-40" />
@@ -36,44 +44,52 @@ export function ChatTab({ messages, input, onInputChange, onSend, isLoading }: C
         {messages.map((msg, i) => (
           <div
             key={i}
-            className={`text-sm rounded-lg px-3 py-2 ${
+            className={`flex ${msg.role === 'user' ? 'justify-end' : 'justify-start'}`}
-              msg.role === 'user'
-                ? 'ml-6 bg-primary/15 text-foreground'
-                : 'mr-2 bg-[rgba(255,255,255,0.04)] border border-border text-foreground'
-            }`}
           >
-            <p className="whitespace-pre-wrap">{msg.content}</p>
+            <div
+              className={`max-w-[85%] rounded-xl px-3.5 py-2.5 text-[0.8125rem] leading-relaxed ${
+                msg.role === 'user'
+                  ? 'bg-primary/15 text-foreground'
+                  : 'bg-[rgba(255,255,255,0.04)] text-foreground border border-[rgba(255,255,255,0.06)]'
+              }`}
+            >
+              <MarkdownContent content={msg.content} className="text-[0.8125rem] leading-relaxed" />
+            </div>
           </div>
         ))}
         {isLoading && (
-          <div className="mr-2 bg-[rgba(255,255,255,0.04)] border border-border rounded-lg px-3 py-2">
+          <div className="flex justify-start">
-            <div className="flex gap-1">
+            <div className="bg-[rgba(255,255,255,0.04)] border border-[rgba(255,255,255,0.06)] rounded-xl px-3.5 py-2.5">
-              <div className="h-1.5 w-1.5 rounded-full bg-primary/60 animate-bounce" />
+              <Loader2 size={16} className="animate-spin text-primary" />
-              <div className="h-1.5 w-1.5 rounded-full bg-primary/60 animate-bounce [animation-delay:0.15s]" />
-              <div className="h-1.5 w-1.5 rounded-full bg-primary/60 animate-bounce [animation-delay:0.3s]" />
             </div>
           </div>
         )}
         <div ref={messagesEndRef} />
       </div>
-      <div className="shrink-0 border-t border-border p-3">
+
+      {/* Input */}
+      <div className="px-4 py-3 border-t shrink-0" style={{ borderColor: 'var(--glass-border)' }}>
         <div className="flex items-end gap-2">
           <textarea
+            ref={inputRef}
             value={input}
             onChange={(e) => onInputChange(e.target.value)}
             onKeyDown={handleKeyDown}
             placeholder="Ask AI to help..."
             rows={1}
-            className="flex-1 resize-none rounded-lg border border-border bg-card px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground focus:border-[rgba(6,182,212,0.3)] focus:outline-none"
+            className="flex-1 resize-none rounded-xl border bg-card text-foreground text-[0.8125rem] placeholder:text-muted-foreground px-3.5 py-2.5 focus:outline-none focus:border-[rgba(6,182,212,0.3)]"
+            style={{ borderColor: 'var(--glass-border)' }}
+            disabled={isLoading}
           />
           <button
             onClick={onSend}
             disabled={!input.trim() || isLoading}
-            className="flex h-9 w-9 shrink-0 items-center justify-center rounded-lg bg-gradient-brand text-[#101114] transition-all hover:opacity-90 active:scale-[0.97] disabled:opacity-40"
+            className="bg-gradient-brand text-[#101114] p-2.5 rounded-xl hover:opacity-90 active:scale-[0.97] transition-all disabled:opacity-40"
           >
-            <Send className="h-4 w-4" />
+            <Send size={16} />
           </button>
         </div>
+        <p className="text-[0.625rem] text-muted-foreground mt-1.5 px-1">Shift + Enter for a new line</p>
       </div>
     </div>
   )

frontend/src/components/editor-ai/EditorAIPanel.tsx

@@ -6,6 +6,8 @@ import { ChatTab } from './ChatTab'
 import { SuggestionsTab } from './SuggestionsTab'
 import type { EditorAIChatMessage, AISuggestion } from '@/types'
 
+const PANEL_WIDTH = 380
+
 interface EditorAIPanelProps {
   isOpen: boolean
   onClose: () => void
@@ -23,6 +25,8 @@ interface EditorAIPanelProps {
 
 type Tab = 'chat' | 'suggestions'
 
+export { PANEL_WIDTH }
+
 export function EditorAIPanel({
   isOpen,
   onClose,
@@ -45,28 +49,37 @@ export function EditorAIPanel({
 
   return (
     <div
-      className="fixed right-0 top-0 bottom-0 z-50 flex flex-col border-l"
+      className="fixed right-0 bottom-0 z-40 flex flex-col border-l"
       style={{
-        width: '380px',
+        top: '56px',
+        width: `${PANEL_WIDTH}px`,
         background: 'rgba(16, 17, 20, 0.95)',
         backdropFilter: 'var(--glass-blur)',
         WebkitBackdropFilter: 'var(--glass-blur)',
         borderColor: 'var(--glass-border)',
+        animation: 'slideInRight 200ms ease-out',
       }}
     >
-      <div className="flex items-center justify-between border-b px-3 py-2.5 shrink-0" style={{ borderColor: 'var(--glass-border)' }}>
+      {/* Header */}
+      <div
+        className="flex items-center justify-between px-4 py-3 border-b shrink-0"
+        style={{ borderColor: 'var(--glass-border)' }}
+      >
         <div className="flex items-center gap-2">
-          <Sparkles className="h-4 w-4 text-primary" />
+          <Sparkles size={16} className="text-primary" />
-          <span className="text-sm font-medium text-foreground">AI Assist</span>
+          <span className="text-sm font-semibold text-foreground">AI Assist</span>
         </div>
         <button
           onClick={onClose}
-          className="flex h-6 w-6 items-center justify-center rounded-md text-muted-foreground hover:bg-[rgba(255,255,255,0.06)] hover:text-foreground transition-colors"
+          className="p-1.5 rounded-lg hover:bg-[rgba(255,255,255,0.06)] text-muted-foreground hover:text-foreground transition-colors"
         >
-          <X className="h-3.5 w-3.5" />
+          <X size={16} />
         </button>
       </div>
+
       <NodeSummary node={focalNode} flowName={flowName} flowType={flowType} nodeCount={nodeCount} />
+
+      {/* Tabs */}
       <div className="flex border-b shrink-0" style={{ borderColor: 'var(--glass-border)' }}>
         <button
           onClick={() => setActiveTab('chat')}
@@ -96,6 +109,7 @@ export function EditorAIPanel({
           )}
         </button>
       </div>
+
       {activeTab === 'chat' ? (
         <ChatTab messages={messages} input={input} onInputChange={onInputChange} onSend={onSend} isLoading={isLoading} />
       ) : (

frontend/src/components/editor-ai/NodeSummary.tsx

@@ -22,7 +22,7 @@ const NODE_COLORS: Record<string, string> = {
 export function NodeSummary({ node, flowName, flowType, nodeCount }: NodeSummaryProps) {
   if (!node) {
     return (
-      <div className="border-b border-border px-3 py-2.5">
+      <div className="border-b px-3 py-2.5" style={{ borderColor: 'var(--glass-border)' }}>
         <div className="flex items-center gap-2">
           <Layout className="h-3.5 w-3.5 text-muted-foreground" />
           <span className="text-xs font-medium text-foreground truncate">
@@ -41,7 +41,7 @@ export function NodeSummary({ node, flowName, flowType, nodeCount }: NodeSummary
   const colorClass = NODE_COLORS[node.type] || 'text-muted-foreground'
 
   return (
-    <div className="border-b border-border px-3 py-2.5">
+    <div className="border-b px-3 py-2.5" style={{ borderColor: 'var(--glass-border)' }}>
       <div className="flex items-center gap-2">
         <Icon className={`h-3.5 w-3.5 ${colorClass}`} />
         <span className="font-label text-[0.625rem] uppercase tracking-[0.1em] text-muted-foreground">

frontend/src/index.css

@@ -162,6 +162,11 @@
   to { transform: translateY(0); opacity: 1; }
 }
 
+@keyframes slideInRight {
+  from { transform: translateX(100%); }
+  to { transform: translateX(0); }
+}
+
 @keyframes fadeInRight {
   from { transform: translateX(30px); opacity: 0; }
   to { transform: translateX(0); opacity: 1; }

frontend/src/pages/ProceduralEditorPage.tsx

@@ -10,7 +10,7 @@ import { getScheduleSummary } from '@/components/procedural-editor/scheduleUtils
 import { StepList } from '@/components/procedural-editor/StepList'
 import { TagInput } from '@/components/common/TagInput'
 import { Spinner } from '@/components/common/Spinner'
-import { EditorAIPanel } from '@/components/editor-ai/EditorAIPanel'
+import { EditorAIPanel, PANEL_WIDTH } from '@/components/editor-ai/EditorAIPanel'
 import { ContextMenu } from '@/components/common/ContextMenu'
 import { useEditorAI } from '@/hooks/useEditorAI'
 import { cn } from '@/lib/utils'
@@ -180,7 +180,7 @@ export function ProceduralEditorPage() {
   }
 
   return (
-    <div className={cn('flex h-full flex-col overflow-hidden transition-[padding] duration-200', editorAI.isOpen && 'pr-[380px]')}>
+    <div className="flex h-full flex-col overflow-hidden transition-[padding] duration-200" style={{ paddingRight: editorAI.isOpen ? `${PANEL_WIDTH}px` : 0 }}>
       {/* Toolbar — sticky */}
       <div className="flex shrink-0 items-center justify-between border-b border-border bg-card px-4 py-2">
         <div className="flex items-center gap-3">

frontend/src/pages/TreeEditorPage.tsx

@@ -17,7 +17,7 @@ import { cn, safeGetItem } from '@/lib/utils'
 import { toast } from '@/lib/toast'
 import { FlowAnalyticsPanel } from '@/components/analytics/FlowAnalyticsPanel'
 import { ExportFlowModal } from '@/components/library/ExportFlowModal'
-import { EditorAIPanel } from '@/components/editor-ai/EditorAIPanel'
+import { EditorAIPanel, PANEL_WIDTH } from '@/components/editor-ai/EditorAIPanel'
 import { ContextMenu } from '@/components/common/ContextMenu'
 import { useEditorAI } from '@/hooks/useEditorAI'
 import { findNodeInTree } from '@/store/treeEditorStore'
@@ -522,7 +522,7 @@ export function TreeEditorPage() {
   }
 
   return (
-    <div className={cn('flex h-full flex-col overflow-hidden transition-[padding] duration-200', editorAI.isOpen && 'pr-[380px]')}>
+    <div className="flex h-full flex-col overflow-hidden transition-[padding] duration-200" style={{ paddingRight: editorAI.isOpen ? `${PANEL_WIDTH}px` : 0 }}>
 
       {/* Draft Restore Prompt */}
       {showDraftPrompt && (