:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;
    --bg-color: #f8fafc;
    --bg-secondary: #ffffff;
    --text-color: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --sidebar-width: 250px;
    --header-height: 64px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* Layout */
.app-container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    overflow-y: auto;
    transition: transform 0.3s ease;
    z-index: 1000;
}

.sidebar-header {
    padding: 1.5rem 1rem;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
}

.sidebar-nav {
    padding: 1rem 0;
}

.nav-item {
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-color);
    text-decoration: none;
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.nav-item:hover {
    background-color: var(--bg-color);
    border-left-color: var(--primary-color);
}

.nav-item.active {
    background-color: #eff6ff;
    border-left-color: var(--primary-color);
    color: var(--primary-color);
    font-weight: 500;
}

.nav-item i {
    width: 20px;
    text-align: center;
}

/* Main Content */
.main-content {
    margin-left: var(--sidebar-width);
    flex: 1;
    min-height: 100vh;
}

.header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-actions {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    background: var(--bg-color);
}

.content-wrapper {
    padding: 2rem;
}

/* Cards */
.card {
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    margin-bottom: 1.5rem;
}

.card-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.card-body {
    padding: 1.5rem;
}

.card-footer {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
    background: var(--bg-color);
}

/* Buttons */
.btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 0.375rem;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-hover);
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-success:hover {
    background: #059669;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background: #dc2626;
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background: #475569;
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-color);
}

.btn-outline:hover {
    background: var(--bg-color);
}

.btn-sm {
    padding: 0.375rem 0.75rem;
    font-size: 0.8125rem;
}

.btn-group {
    display: flex;
    gap: 0.5rem;
}

/* Forms */
.form-group {
    margin-bottom: 1.25rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.875rem;
}

.form-control {
    width: 100%;
    padding: 0.625rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.375rem;
    font-size: 0.875rem;
    transition: all 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23334155' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    padding-right: 2.5rem;
}

textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

.form-error {
    color: var(--danger-color);
    font-size: 0.8125rem;
    margin-top: 0.25rem;
}

.form-success {
    color: var(--success-color);
    font-size: 0.8125rem;
    margin-top: 0.25rem;
}

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

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

th {
    background: var(--bg-color);
    padding: 0.75rem 1rem;
    text-align: left;
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.875rem;
}

tr:hover {
    background: var(--bg-color);
}

/* Stats Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-color);
}

.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.stat-icon.primary {
    background: #eff6ff;
    color: var(--primary-color);
}

.stat-icon.success {
    background: #f0fdf4;
    color: var(--success-color);
}

.stat-icon.warning {
    background: #fffbeb;
    color: var(--warning-color);
}

.stat-icon.danger {
    background: #fef2f2;
    color: var(--danger-color);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 2000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 0.25rem;
}

.modal-close:hover {
    background: var(--bg-color);
}

.modal-body {
    padding: 1.5rem;
}

.modal-footer {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 0.75rem;
    justify-content: flex-end;
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 0.375rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
}

.alert-success {
    background: #f0fdf4;
    color: #15803d;
    border: 1px solid #bbf7d0;
}

.alert-danger {
    background: #fef2f2;
    color: #b91c1c;
    border: 1px solid #fecaca;
}

.alert-warning {
    background: #fffbeb;
    color: #b45309;
    border: 1px solid #fde68a;
}

.alert-info {
    background: #eff6ff;
    color: #1e40af;
    border: 1px solid #bfdbfe;
}

/* Badge */
.badge {
    display: inline-block;
    padding: 0.25rem 0.625rem;
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: 9999px;
}

.badge-primary {
    background: #eff6ff;
    color: var(--primary-color);
}

.badge-success {
    background: #f0fdf4;
    color: var(--success-color);
}

.badge-danger {
    background: #fef2f2;
    color: var(--danger-color);
}

.badge-warning {
    background: #fffbeb;
    color: var(--warning-color);
}

/* Pagination */
.pagination {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    margin-top: 1.5rem;
}

.page-link {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.375rem;
    color: var(--text-color);
    text-decoration: none;
    transition: all 0.2s;
}

.page-link:hover {
    background: var(--bg-color);
}

.page-link.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
    }

    .menu-toggle {
        display: block;
    }

    .content-wrapper {
        padding: 1rem;
    }

    .header {
        padding: 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .modal-content {
        width: 95%;
        margin: 1rem;
    }

    .table-wrapper {
        overflow-x: scroll;
    }

    table {
        min-width: 600px;
    }
}

@media (max-width: 480px) {
    .stat-value {
        font-size: 1.5rem;
    }

    .card-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .btn-group {
        flex-direction: column;
        width: 100%;
    }

    .btn-group .btn {
        width: 100%;
        justify-content: center;
    }
}

/* Loading Spinner */
.spinner {
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.9);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 3000;
}

.loading-overlay.active {
    display: flex;
}

/* Utilities */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-muted { color: var(--text-secondary); }
.text-primary { color: var(--primary-color); }
.text-success { color: var(--success-color); }
.text-danger { color: var(--danger-color); }
.text-warning { color: var(--warning-color); }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

.d-flex { display: flex; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }

.w-full { width: 100%; }
.hidden { display: none; }