body { 
    margin: 0; 
    padding-bottom: 3rem; 
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; 
    background: #f0f0f0;
}
#form { 
    background: rgba(255,255,255,0.9); 
    padding: 0.5rem; 
    position: fixed; 
    bottom: 0; 
    left: 0; 
    right: 0; 
    display: flex; 
    height: 3rem; 
    box-sizing: border-box; 
    border-top: 1px solid #ddd;
}
#input { 
    border: none; 
    padding: 0 1rem; 
    flex-grow: 1; 
    border-radius: 2rem; 
    margin-right: .5rem;
    border: 1px solid #ddd;
}
#form > button { 
    background: #007bff; 
    border: none; 
    padding: 0 1rem; 
    border-radius: 5px; 
    outline: none; 
    color: #fff; 
}
#messages { 
    list-style-type: none; 
    margin: 0; 
    padding: 0; 
}
#messages > li { 
    padding: 0.5rem 1rem; 
}
#messages > li:nth-child(odd) { 
    background: #e6e6e6; 
}