#bbpress-forums{
  display:flex;
  flex-direction:column;
}
.bbp-reply-form{
  order:1;
  width:95%;
}
#bbpress-forums div:nth-of-type(2){
  order:2;
}
ul.bbp-replies{
  order:3;
  width:95%;
}
#bbpress-forums div:nth-last-of-type(2){
  order:4;
}