body {
    font-family: Arial, sans-serif;
    margin: 0;
    background: #f4f6f8;
    color: #1f2937;
}

header {
    background: #0f172a;
    color: white;
    padding: 1rem 2rem;
}

nav a {
    color: #cbd5e1;
    margin-right: 1rem;
    text-decoration: none;
}

main {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.notice {
    padding: 1rem;
    border-radius: 8px;
    background: #e2e8f0;
    margin: 1rem 0;
}

.notice.warning {
    background: #fef3c7;
}

.notice.error {
    background: #fecaca;
}

form {
    display: grid;
    gap: 0.75rem;
    max-width: 420px;
}

input, button {
    padding: 0.7rem;
    font-size: 1rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

th, td {
    border: 1px solid #cbd5e1;
    padding: 0.6rem;
    text-align: left;
}