body {
    color: #89a45e;
    background: url("background.jpg") no-repeat center center fixed;
    background-size: cover;
    text-align: center;
}

h1 {
    line-height: 1.5em;
    margin-bottom: 1.5em;
}

.outer {
    display: table;
    position: absolute;
    top: 0;
    left: 0;
    height: 50%;
    width: 100%;
}

.middle {
    display: table-cell;
    vertical-align: middle;
}

.inner {
    margin-left: auto;
    margin-right: auto;
    width: 50%;
}

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
}

li {
    margin: 20px 0 20px 0;
    display: flex;
    justify-content: center;
}

a {
    display: block;
    width: 100px;
    text-decoration: none;
    background-color: #333333;
    border-radius: 5px;
    color:#fff;
    padding:10px 10px 10px 10px;
}

a:hover {
    background-color: #596b3d;
}