social/mail_tracking/static/src/css/mail_tracking.css

/* Copyright 2016 Antonio Espinosa - <antonio.espinosa@tecnativa.com>
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html). */

.mail_tracking span {
    color: #909090;
}
.mail_tracking_pointer {
    cursor: pointer;
}

.mail_tracking span.mail_tracking_opened {
    color: #a34a8b;
}

.o_mail_thread .o_thread_message .o_thread_message_core .o_mail_info {
    margin: 0;
}

.o_mail_thread .o_thread_message .o_thread_message_core .o_mail_tracking {
    margin: 0 0 2px 0;
}