body {
    margin: 0;
    padding: 0;
    height: 100.001vh;
}

div {
    box-sizing: border-box;
}

.messages {
    padding: 1em;
    display: flex;
    flex-direction: column-reverse;
    height: 95vh;
    overflow: auto;
}

.messages .message {
    padding: 0.5em;
    border: 1px solid #aaa;
    border-radius: 5px;
    margin-bottom: 0.5em;
}

.chatter {
    font-weight: bold;
}

.chat-input {
    position: fixed;
    bottom: 0;
    width: 100%;
    box-sizing: border-box;
    padding: 0.5em;
    background-color: #fff;
    border-top: 1px solid #ccc;
    height: 5vh;
}
.chat-input > form {
    display: flex;
    width: 100%;
    box-sizing: border-box;
}
.chat-input > form > input,
.chat-input > form > submit {
    padding: 0.7em;
    margin-right: 0.4em;
}
.chat-input > form > input[name="chatter"] {
    width: 20%;
}
.chat-input > form > input[name="message"] {
    width: 75%;
}