discourse/plugins/chat/assets/stylesheets/common/chat-message-blocks.scss

.chat-message__blocks {
  padding-block: 0.5em;
  display: flex;
  flex-direction: column;
  gap: 0.5em;
}

.chat-message__block {
  .block__actions {
    display: flex;
    gap: 0.5em;
  }

  .block__button {
    .emoji {
      height: 18px;
      width: 18px;
    }
  }
}