viewer.css

body, * {
    margin: 0;
    padding: 0;
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}
header {
    margin: 0;
    padding: 2px 10px;
    height: 20px;
    background-color: darkGrey;
    background: linear-gradient(to bottom, rgb(100,125,75), rgb(30,60,10));
    background: -webkit-linear-gradient(top, rgb(100,125,75) 0%, rgb(30,60,10) 100%);

    font-size: 18px;
    font-variant: small-caps;
    color: white;
    margin: 0;
    line-height: 20px;
    vertical-align: top;
}
header h1 {
    font-size: inherit;
    line-height: inherit;
    vertical-align: inherit;
    margin: inherit;

    display: inline;
    font-weight: bold;
    letter-spacing: 1.5px;
}
header a {
    color: inherit;
    text-decoration: inherit;
}
header ul {
    margin: 0;
    display: inline;
    float: right;
}
header li {
    display: inline;
    list-style-type: none;
}
header li:not(:last-child):after {
    content: " — ";
}
#drop {
    margin: 15px auto;
    width: 400px;
    height: 400px;
}

#drop p {
    background-color: rgb(100,125,75);
    box-shadow: inset 0 0 5px rgb(30,60,10);
    color: white;
    line-height: 400px;
    text-align: center;
    vertical-align: middle;
}
#drop.hover p {
    background: radial-gradient(ellipse at center, rgb(100,125,75), rgb(30,60,10));
    background: -webkit-radial-gradient(ellipse, rgb(100,125,75), rgb(30,60,10));
}
#load {
    position: absolute;
    top: -100px;
    left: -100px;
    visibility: hidden;
}
footer {
    text-align: center;
    font-size: 0.7em;
}