diff --git a/web/src/app/(main)/system/llm/page.tsx b/web/src/app/(main)/system/llm/page.tsx
index 85fbcd0..8e5e491 100644
--- a/web/src/app/(main)/system/llm/page.tsx
+++ b/web/src/app/(main)/system/llm/page.tsx
@@ -141,7 +141,11 @@ function NewProfileDialog({ onCreated }: { onCreated: (id: string) => void }) {
           <PlusIcon /> 新建
         </Button>
       </DialogTrigger>
-      <DialogContent className="sm:max-w-lg">
+      <DialogContent
+        className="sm:max-w-lg"
+        // don't dismiss a half-filled form on an outside click (Esc / ✕ still close).
+        onInteractOutside={(e) => e.preventDefault()}
+      >
         <DialogHeader>
           <DialogTitle>新建 Profile</DialogTitle>
           <DialogDescription>新建后不会自动激活，请在列表中「设为激活」以启用。</DialogDescription>
diff --git a/web/src/components/ui/dialog.tsx b/web/src/components/ui/dialog.tsx
index d9aecca..230ffd5 100644
--- a/web/src/components/ui/dialog.tsx
+++ b/web/src/components/ui/dialog.tsx
@@ -61,7 +61,7 @@ function DialogContent({
       <DialogPrimitive.Content
         data-slot="dialog-content"
         className={cn(
-          "fixed top-1/2 left-1/2 z-50 grid w-full max-w-[calc(100%-2rem)] -translate-x-1/2 -translate-y-1/2 gap-4 rounded-xl bg-popover p-4 text-sm text-popover-foreground ring-1 ring-foreground/10 duration-100 outline-none sm:max-w-sm data-open:animate-in data-open:fade-in-0 data-open:zoom-in-95 data-closed:animate-out data-closed:fade-out-0 data-closed:zoom-out-95",
+          "fixed top-1/2 left-1/2 z-50 grid max-h-[90dvh] w-full max-w-[calc(100%-2rem)] -translate-x-1/2 -translate-y-1/2 gap-4 overflow-y-auto rounded-xl bg-popover p-4 text-sm text-popover-foreground ring-1 ring-foreground/10 duration-100 outline-none sm:max-w-sm data-open:animate-in data-open:fade-in-0 data-open:zoom-in-95 data-closed:animate-out data-closed:fade-out-0 data-closed:zoom-out-95",
           className
         )}
         {...props}
diff --git a/web/src/components/ui/textarea.tsx b/web/src/components/ui/textarea.tsx
index 04d27f7..db2e834 100644
--- a/web/src/components/ui/textarea.tsx
+++ b/web/src/components/ui/textarea.tsx
@@ -7,7 +7,10 @@ function Textarea({ className, ...props }: React.ComponentProps<"textarea">) {
     <textarea
       data-slot="textarea"
       className={cn(
-        "flex field-sizing-content min-h-16 w-full rounded-lg border border-input bg-transparent px-2.5 py-2 text-base transition-colors outline-none placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 disabled:cursor-not-allowed disabled:bg-input/50 disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-3 aria-invalid:ring-destructive/20 md:text-sm dark:bg-input/30 dark:disabled:bg-input/80 dark:aria-invalid:border-destructive/50 dark:aria-invalid:ring-destructive/40",
+        // field-sizing-content auto-grows the textarea to its content; cap the
+        // growth (and scroll past it) so a large paste can't blow a dialog past the
+        // viewport. Call sites can override via a max-h-* class (twMerge wins).
+        "flex field-sizing-content max-h-[45vh] min-h-16 w-full overflow-auto rounded-lg border border-input bg-transparent px-2.5 py-2 text-base transition-colors outline-none placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 disabled:cursor-not-allowed disabled:bg-input/50 disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-3 aria-invalid:ring-destructive/20 md:text-sm dark:bg-input/30 dark:disabled:bg-input/80 dark:aria-invalid:border-destructive/50 dark:aria-invalid:ring-destructive/40",
         className
       )}
       {...props}