body {
    background: black no-repeat;
    background-size: cover;
    background-position: relative;
}

div#nav {
    width: 450px;
    margin: 0 auto;
    padding-top: 20px;
}

div#main {
    width: 450px;
    margin: 0 auto;
}

img {
    width: 100%;
}

img.main {
    width: 100%;
}

@media (orientation: portrait) {
    div {
        width: 90%;
    }
}

p {
    color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
}

blockquote {
    color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
    text-align: justify;
}

li {
    color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
}

p.justify {
    color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
    text-align: justify;
}

p.centre {
    color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

h1 {
    color: lightgray;
    float: center;
    font-size: 18pt;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

h2 {
    color: lightgray;
    float: center;
    font-size: 14pt;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

h3 {

    color: lightgray;
    float: center;
    font-size: 12pt;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

h4 {

    color: lightgray;
    float: center;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

h5 {

    color: lightgray;
    float: center;
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
}

a {
    color: orange;
    font-family: Arial, Helvetica, sans-serif;
}

nav {
    text-align: center;
    color: lightgray;
}

nav#maths {
    padding-top: 5px;
}

button {
    background-color: transparent;
    border-color: transparent;
    color: orange;
    font-family: Arial, Helvetica, sans-serif;
    font-size: 12pt;
    text-align: center;
    padding-left: 0px;
    padding-right: 0px;
}