header,
form,
nav {
    text-align: center;
}

form {
    margin-bottom: 2em;
}

form th,
form td {
    text-align: left;
}

table input {
    width: 20em;
}

table {
    margin-left: auto;
    margin-right: auto;
    border-spacing: 3px 6px;
    padding: 0 3px;
}

.icons {
    margin-top: 1em;
    margin-bottom: 1em;
    border: 3px #333333 solid;
}

form th,
.icons td,
.icons th {
    background: #333333;
    padding: 3px;
}

.icon {
    text-align: center;
}