diff --git a/app/canvas/[id]/page.tsx b/app/canvas/[id]/page.tsx
index 03aa8c12a..03f217ff0 100644
--- a/app/canvas/[id]/page.tsx
+++ b/app/canvas/[id]/page.tsx
@@ -739,6 +739,7 @@ export default function CanvasEditorPage({ params }: PageProps) {
         <div className="relative h-dvh w-full overflow-hidden bg-background">
           {brandEntry}
           {agentDisabledNotice}
+          <div className="absolute left-0 right-0 top-[72px] z-10 border-t border-black/10 dark:border-white/10" />
 
           <div className="absolute inset-0 flex pt-[72px]">
             <div className="min-w-0 flex-1 border-r bg-white dark:bg-zinc-950">
diff --git a/components/agents/AgentPresetDialog.tsx b/components/agents/AgentPresetDialog.tsx
index 7c03135c6..a574c47a2 100644
--- a/components/agents/AgentPresetDialog.tsx
+++ b/components/agents/AgentPresetDialog.tsx
@@ -372,15 +372,15 @@ export function AgentPresetDialog({
             <div className="grid grid-cols-1 gap-3 md:grid-cols-2">
               <div className="space-y-2">
                 <div className="text-sm font-medium">预览图</div>
-                <div className="flex items-center gap-3">
+                <div className="flex items-start gap-4">
                   {avatarUrl ? (
                     <img
                       src={avatarUrl}
                       alt="智能体预览图"
-                      className="h-14 w-14 rounded-2xl border object-cover"
+                      className="h-24 w-24 rounded-2xl border object-cover shadow-sm"
                     />
                   ) : (
-                    <div className="flex h-14 w-14 items-center justify-center rounded-2xl border bg-muted text-xs text-muted-foreground">
+                    <div className="flex h-24 w-24 items-center justify-center rounded-2xl border bg-muted text-sm text-muted-foreground shadow-sm">
                       未上传
                     </div>
                   )}
@@ -398,13 +398,14 @@ export function AgentPresetDialog({
                       type="button"
                       variant="outline"
                       size="sm"
+                      className="h-11 px-5 text-base"
                       onClick={() => avatarInputRef.current?.click()}
                       disabled={avatarUploading}
                     >
                       {avatarUploading ? (
-                        <Loader2 className="mr-1 h-4 w-4 animate-spin" />
+                        <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                       ) : (
-                        <Upload className="mr-1 h-4 w-4" />
+                        <Upload className="mr-2 h-4 w-4" />
                       )}
                       上传预览图
                     </Button>