odoo/addons/mail/static/src/css/mail.css

/** ThreadView widget **/

.oe_mail_main {
}

.oe_mail_actions {
    padding-bottom: 10px;
}

.oe_mail_post_comment {
    width: 65%;
    padding-bottom: 10px;
}

.oe_mail_comments {
    width: 65%;
}

.oe_mail_msg {
    width: 65%;
/*     border: 1px solid #998877; */
    padding: 10px 0px 10px 0px;
}

.oe_mail_msg:after {
  content: "";
  display: block;
  clear: both; 
}

.oe_mail_msg_image {
    float: left;
    width: 9%;
}

.oe_mail_msg_content {
    width: 89%;
    margin-left: 10%;
/*     border: 1px solid #557722; */
    overflow: hidden;
}

.oe_mail_msg_p {
    padding: 0;
    margin: 0;
}

.oe_mail_msg_body {
}

.oe_mail_msg_author {
    color: #4E43E7;
}

.oe_mail_msg_need_action {
    color: #C03000;
}

.oe_mail_msg_date {
    color: #4E43E7;
}