html, body {
    font-family: monospace;
    font-size: 1rem;
    margin: 0;
    padding: 0;
}
main {
    margin: 2rem;
}
nav ul {
    display: flex;
    margin: 0;
    padding: 0;
}
nav li {
    flex: 1 1 0;
    list-style-type: none;
    margin: 0;
    padding: 0;
}
nav a, nav span {
    border-right: 2px solid #aaa;
    border-bottom: 2px solid #aaa;
    display: block;
    padding: 1.5rem;
    text-align: center;
    text-decoration: none;
}
nav a {
    color: #000;
}
nav a:hover, nav li[aria-current="page"] {
    background-color: #000;
    color: #fff;
}
nav li:last-child, nav li:last-child a {
    border-right: none;
}
input {
    background-color: #fff;
    border: 1px solid #000;
    box-sizing: border-box;
    font-family: monospace;
    font-size: 1rem;
    margin: 1rem 0;
    padding: 0.5rem;
    width: 30rem;
}
.register input[type="submit"], .transfer input[type="submit"] {
    width: 50rem;
}
.login input[type="submit"], .cash-transaction input[type="submit"] {
    width: 45rem;
}
label {
    display: inline-block;
}
.register label, .transfer label {
    width: 20rem;
}
.login label, .cash-transaction label {
    width: 15rem;
}
p.error {
    color: #a00;
    font-weight: bold;
}
p.success {
    color: #080;
    font-weight: bold;
}
.negative {
    color: #800;
}
table {
    border-spacing: 0;
}
td {
    padding: 0 1rem;
}
tr:nth-child(2n) {
    background-color: #eee;
}
tr:last-child {
    font-weight: bold;
}
td:last-child {
    text-align: right;
}
.pre {
    white-space: pre-wrap;
}