body {
    font-family: sans-serif;
    margin: 0;
}
main {
    margin-left: 250px;
    padding: 20px;
    transition: margin-left 0.3s ease;
}
.header {
    margin-left: 250px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    background-color: #d9534f;
    color: white;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}
.header-left h1 {
    font-size: 1.5em;
    margin: 0;
    font-weight: normal;
}
.header-right {
    font-size: 1.1em;
}
.invoices-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}
.filter-buttons {
    display: flex;
    gap: 10px;
}
.filter-btn {
    padding: 10px 20px;
    border: 1px solid #d9534f;
    border-radius: 5px;
    background-color: #fff;
    color: #d9534f;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.3s ease, color 0.3s ease;
}
.filter-btn:hover {
    background-color: #f7e0df;
}
.filter-btn.active {
    background-color: #d9534f;
    color: white;
}
.delete-btn {
    padding: 10px 20px;
    background-color: #dc3545;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.3s ease;
}
.delete-btn:disabled {
    background-color: #b3b3b3;
    cursor: not-allowed;
}
.delete-btn:hover:enabled {
    background-color: #c82333;
}
#invoices-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 20px;
}
.invoice-card {
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    padding: 20px;
    display: flex;
    flex-direction: column;
    position: relative;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.invoice-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}
.invoice-card.selected {
    border-color: #d9534f;
    box-shadow: 0 0 10px rgba(217, 83, 79, 0.5);
}
.invoice-checkbox {
    position: absolute;
    top: 10px;
    right: 10px;
    width: 20px;
    height: 20px;
    cursor: pointer;
}
.invoice-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #eee;
}
.invoice-header h3 {
    margin: 0;
    font-size: 1.2em;
    color: #333;
}
.invoice-header span {
    color: #777;
    font-size: 0.9em;
}
.invoice-details {
    margin-bottom: 15px;
}
.invoice-details table {
    width: 100%;
    border-collapse: collapse;
}
.invoice-details th, .invoice-details td {
    text-align: left;
    padding: 8px 0;
    border-bottom: 1px dashed #eee;
}
.invoice-details th {
    font-weight: bold;
    color: #555;
}
.invoice-details td {
    color: #666;
}
.invoice-total {
    text-align: right;
    font-size: 1.3em;
    font-weight: bold;
    color: #d9534f;
    padding-top: 10px;
    border-top: 2px solid #eee;
}
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    justify-content: center;
    align-items: center;
}
.modal-content {
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    text-align: center;
    max-width: 400px;
    width: 90%;
}
.modal-content h2 {
    margin-top: 0;
    color: #333;
}
.modal-content p {
    color: #555;
}
.modal-actions {
    margin-top: 20px;
    display: flex;
    justify-content: center;
    gap: 10px;
}
.button {
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}
.cancel {
    background-color: #ccc;
    color: #333;
}
.delete {
    background-color: #dc3545;
    color: white;
}
.close-button {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 2em;
    font-weight: bold;
    cursor: pointer;
    color: #aaa;
}
.close-button:hover {
    color: #000;
}