body {
    font-family: sans-serif;
	margin: 2em;
}

h1 {
    color: darkblue;
    text-align: center;
}

h2 {
    color: darkblue;
}

.error {
    color: red;
}

#main {
    margin-left: auto;
    margin-right: auto;
}

#truthtable thead {
    font-weight: bold;
    background: #ccf;
}

#truthtable tr.zero {
    background: #eee;
}

#truthtable tr.one {
    background: #cfc;
}

#truthtable td {
    width: 4em;
    text-align: center;
}