synapse-product/res/templates-vector/mail.css

body {
    margin: 0px;
}

#page {
    font-family: 'Open Sans', Helvetica, Arial, Sans-Serif;
    font-size: 12pt;

    margin: auto;
    max-width: 640px;
    padding: 20px;
}

.header {
    height: 87px;
    border-bottom: 4px solid #e4f7ed;
}

.logo {
    float: right;
    margin-left: 20px;
}

.salutation {
    padding-top: 10px;
    font-weight: bold;
}

.summarytext {
}

.room_header {
    padding-top: 38px;
    padding-bottom: 10px;
    border-bottom: 1px solid #e5e5e5;
}

.room_header h2 {
    margin-top: 0px;
    margin-left: 75px;
    font-size: 20px;
}

.room_avatar {
    float: left;
    margin-top: -8px;
}

.room_avatar img {
    width: 48px;
    height: 48px;
    object-fit: cover;
    border-radius: 24px;
    margin-left: 7px;
}

.room_content {
    clear: left;
}

.notif {
    border-bottom: 1px solid #e5e5e5;
    margin-top: 16px;
    padding-bottom: 16px;
}

.historical {
    opacity: 0.3;
}

.message {
    position: relative;
    margin-bottom: 10px;
}

.sender_avatar {
    width: 32px;
    height: 32px;
    border-radius: 16px;
    position: absolute;
    margin-left: 14px;
    margin-top: -2px;
}

.sender_name  {
    margin-left: 75px;
    display: inline;
    font-weight: bold;
}

.message_time  {
    float: right;
}

.message_body {
    margin-left: 75px;
}

.notif_link {
    margin-left: 75px;
    font-weight: bold;
}

.notif_link a, .footer a {
    color: #76CFA6;
    text-decoration: none;
}

.footer {
    margin-top: 20px;
    text-align: center;
}