.invoice-btn {
    background-color: #007BFF; /* Bootstrap blue */
    color: white;
    border: none;
    padding: 5px 10px;
    border-radius: 4px;
    cursor: pointer;
}
.invoice-btn:hover {
    background-color: #0056b3; /* darker blue on hover */
}

.main-nav {
    background-color: #007BFF; /* Blue bar */
    padding: 10px;
    text-align: center;
}

.main-nav a {
    color: white;
    margin: 0 15px;
    text-decoration: none;
    font-weight: bold;
    font-size: 16px;
}

.main-nav a:hover {
    text-decoration: underline;
}