zulip/web/styles/scheduled_messages.css

#scheduled_messages_overlay_container {
    .no-overlay-messages {
        display: none;

        &:only-child {
            display: block;
        }
    }
}

#scheduled_message_indicator {
    display: block;
    margin-left: 10px;
    font-style: italic;
    color: hsl(0deg 0% 53%);
}