body {
    background-color: #f8f9fa;
    font-family: Arial, sans-serif;
}
.error-container {
    margin-top: 100px;
    text-align: center;
}
.error-heading {
    font-size: 4rem;
    font-weight: bold;
    color: #dc3545;
}
.error-message {
    font-size: 1.5rem;
    margin-top: 20px;
}
.btn-back {
    margin-top: 30px;
}