article {
    background-color: #eeeeff;
    line-height: 180%;
}

header nav a {
    background: #2681a4;
    color:#fff;
    text-align: center;
    text-decoration: none;
    padding:10px;
    border: 1px solid lightgray;
    /* Flexbox */
    flex-grow:1;
}

header nav a:hover {
    background: #4cade7;
}