body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f4f4f4;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1, h2 {
    color: #0056b3;
}

.filters-card, .user-list-section, .send-email-card {
    background-color: #e9f5ff;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    border: 1px solid #cce5ff;
}

.filters-card h2, .user-list-section h2, .send-email-card h2 {
    margin-top: 0;
    color: #0056b3;
}

.filter-group {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 10px;
    align-items: center;
}

.filter-group input[type="text"],
.filter-group input[type="number"],
.filter-group select {
    flex: 1;
    min-width: 120px;
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 4px;
}

.filter-group label {
    font-weight: bold;
    margin-right: 5px;
}

button {
    padding: 10px 15px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    margin-right: 10px;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #0056b3;
}

button:disabled {
    background-color: #cccccc;
    cursor: not-allowed;
}

.user-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

.user-table th, .user-table td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}

.user-table th {
    background-color: #f2f2f2;
    color: #333;
}

.user-table tbody tr:nth-child(even) {
    background-color: #f9f9f9;
}

.pagination {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 20px;
}

.pagination button {
    background-color: #6c757d;
}

.pagination button:hover {
    background-color: #5a6268;
}

#pageInfo {
    font-weight: bold;
}

#loadingMessage, #noUsersMessage {
    text-align: center;
    padding: 20px;
    font-style: italic;
    color: #666;
}

#emailStatusMessage {
    padding: 10px;
    border-radius: 5px;
    text-align: center;
    font-weight: bold;
}

#emailStatusMessage.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

#emailStatusMessage.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.6);
    padding-top: 60px;
}

.modal-content {
    background-color: #fefefe;
    margin: 5% auto;
    padding: 30px;
    border: 1px solid #888;
    width: 90%;
    max-width: 600px;
    border-radius: 8px;
    position: relative;
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2), 0 6px 20px 0 rgba(0,0,0,0.19);
    animation-name: animatetop;
    animation-duration: 0.4s
}

@keyframes animatetop {
    from {top: -300px; opacity: 0}
    to {top: 5%; opacity: 1}
}

.close-button {
    color: #aaa;
    position: absolute;
    top: 10px;
    right: 20px;
    font-size: 35px;
    font-weight: bold;
    cursor: pointer;
}

.close-button:hover,
.close-button:focus {
    color: #333;
    text-decoration: none;
}

.open-modal-btn {
    margin-top: 15px;
    margin-bottom: 20px;
    padding: 12px 20px;
    background-color: #28a745;
    font-size: 1.1em;
    font-weight: bold;
    border-radius: 8px;
    transition: background-color 0.3s ease;
}

.open-modal-btn:hover {
    background-color: #218838;
}

.send-email-btn {
    padding: 12px 20px;
    background-color: #007bff;
    font-size: 1.1em;
    font-weight: bold;
    border-radius: 8px;
    margin-top: 15px;
    width: auto;
}

.send-email-btn:hover {
    background-color: #0056b3;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    box-sizing: border-box;
}

@media (max-width: 768px) {
    .modal-content {
        width: 95%;
        margin: 10% auto;
    }
    .filter-group {
        flex-direction: column;
        align-items: stretch;
    }
    .filter-group input,
    .filter-group select,
    .filter-group label {
        width: 100%;
    }
    button {
        width: 100%;
        margin-right: 0;
        margin-bottom: 10px;
    }
}