vector-im-hydrogen-web/src/ui/web/css/timeline.css

.TimelinePanel ul {
    overflow-y: auto;
    overscroll-behavior: contain;
    list-style: none;
    padding: 0;
    margin: 0;
}

.TimelinePanel li {
}

.message-container {
    flex: 0 1 auto;
    max-width: 80%;
    padding: 5px 10px;
    margin: 5px 10px;
    background: blue;
    /* first try break-all, then break-word, which isn't supported everywhere */
    word-break: break-all;  
    word-break: break-word;
}

.message-container .sender {
    margin: 5px 0;
    font-size: 0.9em;
    font-weight: bold;
}

.message-container img {
    display: block;
    width: 100%;
    height: auto;
}

.TextMessageView {
    display: flex;
    min-width: 0;
}

.TextMessageView.own .message-container {
    margin-left: auto;
}

.TextMessageView .message-container time {
    float: right;
    padding: 2px 0 0px 20px;
    font-size: 0.9em;
    color: lightblue;
}

.message-container time {
    font-size: 0.9em;
    color: lightblue;
}

.own time {
    color: lightgreen;
}

.own .message-container {
    background-color: darkgreen;
}

.TextMessageView.pending .message-container {
    background-color: #333;
}

.message-container p {
    margin: 5px 0;
}

.AnnouncementView {
    margin: 5px 0;
    padding: 5px 10%;
    display: flex;
    align-items: center;
}

.AnnouncementView > div {
    margin: 0 auto;
    padding: 10px 20px;
    background-color: #333;
    font-size: 0.9em;
    color: #CCC;
    text-align: center;
}