discourse/app/assets/stylesheets/common/admin/admin_emojis.scss

.admin-contents.admin-emojis {
  #custom_emoji .select-kit,
  .emoji-uploader .select-kit {
    max-width: 210px;
  }
  #custom_emoji td.action {
    text-align: right;
  }
  #emoji-uploader {
    padding: 10px;
    transition: box-shadow ease-in-out 0.25s;
  }
  .uppy-is-drag-over {
    box-shadow: 0 0px 52px 0 #ffffff, 0px 7px 33px 0 var(--tertiary-low);
  }
  #custom_emoji.highlighted {
    background: var(--tertiary-very-low);
    animation: background-fade-highlight 2.5s ease-out;
  }
}