body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f7f7f7;
}
header {
    background-color: #0d6efd;
    color: white;
    padding: 1rem;
    text-align: center;
}
main {
    padding: 1rem;
}
.page {
    display: none;
}
.page.active {
    display: block;
}
button {
    margin: 0.25rem;
    padding: 0.5rem 1rem;
    background-color: #0d6efd;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}
button:hover {
    background-color: #0b5ed7;
}
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}
th, td {
    border: 1px solid #ddd;
    padding: 0.5rem;
    text-align: left;
}
th {
    background-color: #f0f0f0;
}