body {
    margin:0;
    padding:0;
}
main {
    margin:0em 20em 0em 20em;
}
header {
    width: 100%;
    background-color:black;
    padding:1em;
}
header * {
    display: inline;
    color:white;
}

nav {
    display:block
}
nav * {
    padding-right: 1em;
}
code, pre {
    whitespace: normal;
}
.cblock {
    padding-left: 1em;
    padding-right: 1em;
    display: inline-block;
    margin-left: 5em;
    background-color:lightgray;
}
table,td, th {
    text-align:left;
    width: 50em;
    border: 1px solid black;
    border-collapse: collapse;
}