style.css

.panel-default{
    margin-top: 20px;
    height: calc(100vh - 40px);
}

.panel-body{
    height: calc(100vh - 98px);
    flex-direction: column;
    display: flex;
}

.msg{
    width: calc(100% - 75px);
    display: inline;
    margin-right: 10px;
}


pic{
    width: 30px;
    height: 30px;
    background-color: blue;
    display: inline-block;
    border-radius: 50%;
    text-align: center;
    line-height: 2;
    color: white;
}

msg{
    padding: 5px 15px;
    border-radius: 15px;
    margin: 0px 8px 8px;
    display: flex;

}

.ext-msg{
    background-color:#f5f5f5;
}

.int-msg{
    background-color:#e0e0e0;
}

.person-msg{
    padding: 3px;
}

.external-msg{
    display: inline-flex;
    float: left;
}

.internal-msg{
    display: inline-flex;
    float: right;
    justify-content: flex-end;
}

.notify-msg{
    text-align: center;
    margin: 4px;
}

.notify-msg i{
    background-color: #f2ebbb;
    padding: 2px 7px;
    border-radius: 5px;
    color: #525252;
}