Re work modal scrolling

src/app/components/SignUpComplete.svelte

@@ -4,6 +4,8 @@
   import HomeSmile from "@assets/icons/home-smile.svg?dataurl"
   import Icon from "@lib/components/Icon.svelte"
   import Button from "@lib/components/Button.svelte"
+  import Modal from "@lib/components/Modal.svelte"
+  import ModalBody from "@lib/components/ModalBody.svelte"
   import ModalHeader from "@lib/components/ModalHeader.svelte"
   import ModalFooter from "@lib/components/ModalFooter.svelte"
 
@@ -16,20 +18,22 @@
   const back = () => history.back()
 </script>
 
-<form class="column gap-4" onsubmit={preventDefault(next)}>
-  <ModalHeader>
-    {#snippet title()}
-      <div>You're all set!</div>
-    {/snippet}
-  </ModalHeader>
-  <p>
-    You've created your profile, saved your keys, and now you're ready to start chatting — all
-    without asking permission!
-  </p>
-  <p>
-    From your dashboard, you can use invite links, discover community spaces, and keep up-to-date on
-    groups you've already joined. Click below to get started!
-  </p>
+<Modal tag="form" onsubmit={preventDefault(next)}>
+  <ModalBody>
+    <ModalHeader>
+      {#snippet title()}
+        <div>You're all set!</div>
+      {/snippet}
+    </ModalHeader>
+    <p>
+      You've created your profile, saved your keys, and now you're ready to start chatting — all
+      without asking permission!
+    </p>
+    <p>
+      From your dashboard, you can use invite links, discover community spaces, and keep up-to-date
+      on groups you've already joined. Click below to get started!
+    </p>
+  </ModalBody>
   <ModalFooter>
     <Button class="btn btn-link" onclick={back}>
       <Icon icon={AltArrowLeft} />
@@ -40,4 +44,4 @@
       Go to Dashboard
     </Button>
   </ModalFooter>
-</form>
+</Modal>