fix Virtuoso margin, increaseViewportBy flicker

src/components/styled/Board.styled.jsx

@@ -1560,7 +1560,8 @@ export const TopBar = styled.div`
 
 export const BoardForm = styled.div`
   @media (min-width: 480px) {
-    margin-bottom: 25px;
+    margin-bottom: 130px;
+
     .thread-mobile {
       display: none;
     }
@@ -2928,6 +2929,7 @@ export const BoardForm = styled.div`
 
   @media (max-width: 480px) {
     margin-top: -5%;
+    margin-bottom: 335px;
 
     .thread {
       display: none;

src/components/views/Board.jsx

@@ -459,7 +459,7 @@ const Board = () => {
               <PostLoader />
             ) : (
               <Virtuoso
-                increaseViewportBy={{bottom: 1000}}
+                increaseViewportBy={2000}
                 data={selectedFeed}
                 itemContent={(index, thread) => {
                   const { displayedReplies, omittedCount } = filteredRepliesByThread[thread.cid] || {};