/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 2rem 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

header h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

header .subtitle {
    font-size: 1rem;
    opacity: 0.9;
}

/* Navigation */
nav {
    background: white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-menu {
    list-style: none;
    display: flex;
    gap: 0;
}

.nav-link {
    display: block;
    padding: 1rem 1.5rem;
    text-decoration: none;
    color: #666;
    font-weight: 500;
    transition: all 0.3s ease;
    border-bottom: 3px solid transparent;
}

.nav-link:hover {
    color: #667eea;
    background-color: #f8f9fa;
}

.nav-link.active {
    color: #667eea;
    border-bottom-color: #667eea;
}

/* Main Content */
main {
    padding: 2rem 20px;
}

.section {
    display: none;
}

.section.active {
    display: block;
}

.section h2 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    color: #333;
}

/* Cards */
.card {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.card h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: #444;
}

.stats-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.stats-card h3 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
    opacity: 0.9;
    color: white;
}

.stat-value {
    font-size: 3rem;
    font-weight: bold;
}

/* Tables */
.table-container {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

thead {
    background-color: #f8f9fa;
}

th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: #555;
    border-bottom: 2px solid #dee2e6;
}

th.sortable {
    cursor: pointer;
    user-select: none;
}

th.sortable:hover {
    background-color: #e9ecef;
}

.sort-icon {
    font-size: 0.8rem;
    margin-left: 0.25rem;
    color: #999;
}

td {
    padding: 1rem;
    border-bottom: 1px solid #dee2e6;
}

tbody tr:hover {
    background-color: #f8f9fa;
}

.no-data {
    text-align: center;
    color: #999;
    font-style: italic;
    padding: 2rem !important;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #555;
}

input[type="text"],
input[type="url"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

input[type="text"]:focus,
input[type="url"]:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

input.error {
    border-color: #dc3545;
}

.error-message {
    display: block;
    color: #dc3545;
    font-size: 0.875rem;
    margin-top: 0.25rem;
    min-height: 1.25rem;
}

/* Filters */
.filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.filter-input {
    flex: 1;
    min-width: 200px;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

.btn-secondary {
    background-color: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background-color: #5a6268;
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-edit {
    background-color: #28a745;
    color: white;
    margin-right: 0.5rem;
}

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

.btn-delete {
    background-color: #dc3545;
    color: white;
}

.btn-delete:hover {
    background-color: #c82333;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    animation: fadeIn 0.3s ease;
}

.modal.show {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: white;
    padding: 2rem;
    border-radius: 8px;
    max-width: 500px;
    width: 90%;
    position: relative;
    animation: slideIn 0.3s ease;
}

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 1.5rem;
    font-weight: bold;
    color: #999;
    cursor: pointer;
    transition: color 0.3s ease;
}

.close:hover {
    color: #333;
}

.modal-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.modal-actions .btn {
    flex: 1;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    padding: 1rem 1.5rem;
    background-color: #333;
    color: white;
    border-radius: 4px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    opacity: 0;
    transform: translateY(100px);
    transition: all 0.3s ease;
    z-index: 2000;
    max-width: 400px;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

.toast.success {
    background-color: #28a745;
}

.toast.error {
    background-color: #dc3545;
}

.toast.warning {
    background-color: #ffc107;
    color: #333;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from {
        transform: translateY(-50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.5rem;
    }

    .nav-menu {
        flex-direction: column;
    }

    .nav-link {
        border-bottom: none;
        border-left: 3px solid transparent;
    }

    .nav-link.active {
        border-left-color: #667eea;
        border-bottom-color: transparent;
    }

    .filters {
        flex-direction: column;
    }

    .filter-input {
        width: 100%;
    }

    table {
        font-size: 0.875rem;
    }

    th, td {
        padding: 0.75rem 0.5rem;
    }

    .stat-value {
        font-size: 2rem;
    }

    .toast {
        right: 1rem;
        left: 1rem;
        bottom: 1rem;
    }

    .modal-content {
        width: 95%;
        padding: 1.5rem;
    }

    .modal-actions {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    main {
        padding: 1rem 15px;
    }

    .card {
        padding: 1rem;
    }

    .stats-card {
        padding: 1.5rem;
    }
}