chamilo-lms/main/inc/lib/javascript/emojione/css/emojione.css

.emojione {
  /* Emoji Sizing */
  font-size: inherit;
  height: 3ex;
  width: 3.1ex;
  min-height: 20px;
  min-width: 20px;

  /* Inline alignment adjust the margins  */
  display: inline-block;
  margin: -.4ex .15em .2ex;
  line-height: normal;
  vertical-align: sub;
}

img.emojione {
  /* prevent img stretch */
  width: auto;
}