#outer-container {
    min-width: 300px;
    max-width: 800px;
    margin: 0 auto;
}

#buttons {
    font-size: 0;
}
#buttons button {
    font-size: 1rem;
    background: #efefef;
    border: 1px solid silver;
    margin-right: -1px;
}
#buttons button:first-child {
    border-top-left-radius: 0.3em;
    border-bottom-left-radius: 0.3em;
}
#buttons button:last-child {
    border-top-right-radius: 0.3em;
    border-bottom-right-radius: 0.3em;
}
#buttons button:focus {
    outline: none;
    background: #dfdfdf;
}