src/injections/profileindicator_inject.css

ec-user-link.name > *, .thread-message-header__name > span:nth-child(3) > * {
  vertical-align: middle;
}

.profile-indicator {
  margin-left: 4px;
}

.profile-indicator a {
  text-decoration: none!important;
}

@keyframes loading-profile-indicator {
  from {
    opacity: 0.25;
  }

  to {
    opacity: 1;
  }
}

.profile-indicator.profile-indicator--loading a {
  color: #6f6f6f;

  animation-duration: 0.75s;
  animation-name: loading-profile-indicator;
  animation-iteration-count: infinite;
  animation-direction: alternate;
}

.profile-indicator.profile-indicator--first-post a {
  color: #1976D2;
}

.profile-indicator.profile-indicator--other-posts-read a {
  color: #FF8F00;
}

.profile-indicator.profile-indicator--other-posts-unread a {
  color: #C62828;
}

.profile-indicator a {
  opacity: 1;
  transition: opacity 1s, color 1s;
}