discourse/plugins/discourse-presence/assets/stylesheets/presence.scss

.presence-users {
  background-color: $secondary;
  color: $primary-medium;
  display: flex;
  
  span.presence-text {
    margin-left: 5px;
    margin-right: 2px;
    flex: 0 0 auto;
    padding-top: 3px;    
  }

  .presence-avatars {
    display: flex;
    overflow: hidden;
    flex-wrap: wrap;    
  }

  .wave {
    flex: 0 0 auto;
    
    .dot {
      display: inline-block;
      animation: wave 1.8s linear infinite;

      &:nth-child(2) {
        animation-delay: -1.6s;
      }

      &:nth-child(3) {
        animation-delay: -1.4s;
      }
    }
  }

  @keyframes wave {
    0%, 60%, 100% {
      transform: initial;
    }

    30% {
      transform: translateY(-0.2em);
    }
  }
}

.composer-fields .presence-users {
  position: absolute;
  top: 18px;
  right: 40px;
  @media screen and (max-width: $small-width) {
    max-width: 318px;    
    .presence-avatars {
      flex-wrap: nowrap;
    }
  }
}

.mobile-view {
  .presence-users {
    font-size: $font-down-1;
  }
  .composer-fields .presence-users {
    top: 3px;
    right: 65px;
    max-width: 70px;
    .presence-avatars {
      flex-wrap: nowrap;
    }
    .description {
      display:none;
    }
  }
}