.container {
    margin: 150px auto;
    max-width: 700px;
}

body { background-color: #fafafa; font-family: 'Roboto'; }

.content {
    line-height: 1.5;
    padding: 20px 10px;
    border: 10px solid;
    margin: 30px 0;
}

.fade-toggle-button {
    display: block;
}

.box {
    margin-right: 6px;
    width: 300px;
    background-color: #aaa;
    line-height: 8;
    text-align: center;
    display: inline-block;
}

button {
    margin: 10px 0;
}

.fade-in-button,
.fade-out-button {
    display: inline-block;
}