.board-square-poster {
  display: block;
  width: min(360px, calc(100% - 24px));
  aspect-ratio: 1 / 1;
  margin: 14px auto 18px;
  overflow: hidden;
  border-radius: 16px;
  background: #15212b;
  box-shadow: 0 8px 24px rgba(15, 20, 32, .14);
}
.board-square-poster img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
}
.board-chat-poster {
  width: 96px;
  margin: 4px auto;
  border-radius: 12px;
  flex: 0 0 96px;
}