body { 
    background:linear-gradient(to left, #333, #999) 
}

#form { 
    background: rgba(0, 0, 0, 0.15); 
    padding: 0.25rem; 
    position: fixed; 
    bottom: 0; 
    left: 0; 
    right: 0; 
    display: flex; 
    height: 3rem; 
    box-sizing: border-box; 
    backdrop-filter: blur(10px);
}

#input { 
    border: none; 
    padding: 0 1rem; 
    flex-grow: 1; 
    border-radius: 2rem; 
    margin: 0.25rem;
}

#input:focus { 
    outline: none;
}

#form > button { 
    background: #333; 
    border: none; 
    padding: 0 1rem; 
    margin: 0.25rem; 
    border-radius: 3px; 
    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: #efefef;
}