discourse/app/assets/stylesheets/common/base/topic-post.scss

.names {
 float: left;
 .username {
   font-weight: bold;
 }
 span {
   font-size: 13px;
   padding-right: 8px;
   a {
     color: scale-color($primary, $lightness: 30%);
   }
 }
 .fa {
   font-size: 11px;
   margin-left: 3px;
   color: scale-color($primary, $lightness: 40%);
 }
  .new_user a, .user-title, .user-title a {
    color: scale-color($primary, $lightness: 50%);
 }
}