fix challenge edited board style

app/views/challenge/mine.scala.html

@@ -31,13 +31,14 @@ moreJs = js(c, json, true)) {
         <button class="copy button" data-rel="lichess_id_input" data-icon="&quot;"></button>
         <br />
         @trans.theFirstPersonToComeOnThisUrlWillPlayWithYou()
-        <br /><br />
+        <br />
         @if(ctx.isAuth) {
+        <br />
         Or invite a lichess user:<br />
         <form class="user-invite" action="@routes.Challenge.toFriend(c.id)" method="POST">
           <input name="username" class="friend-autocomplete" placeholder="@trans.search()" />
         </form>
-        <br /><br />
+        <br />
         }
         @cancelForm
         }

public/stylesheets/common.css

@@ -2004,6 +2004,9 @@ div.undertable_inner {
 .undertable tr:first-child td {
   border-top: none;
 }
+div.lichess_overboard .mini_board {
+  margin: auto;
+}
 div.lichess_overboard.joining .submit {
   font-size: 1.2em;
   margin-top: 1em;