BODY {background-color:#333;font-family:sans-serif;color:#fff}
INPUT#ip {position:absolute;left:-9999px;top:0}
DIV.center {text-align:center;position:absolute;top:50%;left:0;right:0;transform:translateY(-50%)}
STRONG {font-size:1.2em}
A#copy {display:inline-block;border:1px solid #ccc;padding:5px}