p {
    margin: 0.4em 0 0.2em;
}

input[type=text] {
    width: 500px;
}

.alice, .bob {
    margin: 1em;
    width: 550px;
    padding: 10px;
}

.alice {
    border: 2px solid grey;
    border-left-width: 20px;
}

.bob {
    border: 2px solid grey;
    border-right-width: 20px;
}

.messageleft, .messageright {
    margin: 1em;
    background-color: grey;
    height: 30px;
    text-align: center;
    color: #fff;
    line-height: 30px;
    width: 590px;
}

.messageleft .arrow, .messageright .arrow {
    border-top: 15px solid #fff;
    border-bottom: 15px solid #fff;
    width: 0;
    height: 0;
}

.messageright .arrow {
    float: right;
    border-left: 15px solid grey;
}

.messageleft .arrow {
    float: left;
    border-right: 15px solid grey;
}