style.css

body {
    font-family: arial;
    background-color: black;
    color: white;
    overflow: hidden;
}

h1 {
    text-align: center;
}

#container {
    z-index: -1;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    overflow: hidden;
}

#tileMenu , #score {
    display: none;
    font-size: 2em;
    position: absolute;
    height: 10em;
    top: 50% - 10em;
    right: 0;
    margin-right: 2em;
    list-style-type: none;
}

#tileMenu > li, #score > li {
    background-color: black;
    height: 1em;
    margin-top: ..25em;
    margin-bottom: .25em;
    padding-top: ..25em;
    padding-bottom: .25em;
    border: 1px solid white;
    padding-left: 1em;
    padding-right: 1em;
    text-align: center;
}

#tileMenu > li.selected {
    background-color: green;
}

#help {
    display: block;
    background-color: black;
    margin-top: ..25em;
    margin-bottom: .25em;
    border: 1px solid white;
    padding-left: 1em;
    padding-right: 1em;
    text-align: center;
    position: absolute;
    left: 0em;
    top: 1em;
    width: 20%;
}

#help table{
    border-collapse: collapse;
}

#finish {
    display: none;
    text-align: center;
    bottom: 0;
    margin-bottom: 2em;
    position: absolute;
    width: 100%;
}

#finish > div {
    background-color: black;
    border: 1px solid white;
    text-align: center;
    display: inline-block;
    width: 20em;
}

#tutorial {
    padding: 3em;
    border: 1px solid white;
    background-color: black;
    margin-left: auto;
    margin-right: auto;
    width: 40em;
    display: block;
}

#footer {
    position: absolute;
    bottom: 0;
    margin-bottom: 1em;
    font-size: .8em;
    text-align: center;
    width: 100%;
}