:root {
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-secondary: #64748b;
    --color-success: #10b981;
    --color-danger: #ef4444;
    --color-warning: #f59e0b;
    --color-info: #3b82f6;

    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-text-lighter: #94a3b8;

    --color-bg: #ffffff;
    --color-bg-subtle: #f8fafc;
    --color-bg-muted: #f1f5f9;

    --color-border: #e2e8f0;
    --color-border-light: #f1f5f9;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);

    --radius-sm: 4px;
    --radius: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
}

* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    color: var(--color-text);
    background: var(--color-bg-subtle);
    margin: 0;
    padding: 0;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header & Navigation */
.header {
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing) var(--spacing-md);
    max-width: 1280px;
    margin: 0 auto;
}

.logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    text-decoration: none;
}

.nav {
    display: flex;
    gap: var(--spacing-xs);
    align-items: center;
}

.nav a {
    color: var(--color-text);
    text-decoration: none;
    padding: var(--spacing-sm) var(--spacing);
    border-radius: var(--radius);
    font-weight: 500;
    transition: all 0.15s ease;
}

.nav a:hover {
    background: var(--color-bg-muted);
    color: var(--color-primary);
}

.nav a.active {
    background: var(--color-primary);
    color: white;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing);
}

.user-menu .username {
    color: var(--color-text-light);
    font-weight: 500;
}

/* Breadcrumbs */
.breadcrumbs {
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-sm) var(--spacing-md);
}

.breadcrumbs-content {
    max-width: 1280px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
}

.breadcrumbs a {
    color: var(--color-text-light);
    text-decoration: none;
}

.breadcrumbs a:hover {
    color: var(--color-primary);
}

.breadcrumbs .separator {
    color: var(--color-text-lighter);
}

.breadcrumbs .current {
    color: var(--color-text);
    font-weight: 500;
}

/* Main Content */
.main {
    padding: var(--spacing-lg) var(--spacing-md);
    max-width: 1280px;
    margin: 0 auto;
}

/* Page Header */
.page-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
}

.page-header h1 {
    font-size: 1.875rem;
    font-weight: 700;
    margin: 0;
    color: var(--color-text);
}

/* Cards */
.card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.card-header {
    padding: var(--spacing) var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg-subtle);
}

.card-body {
    padding: var(--spacing-md);
}

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

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--color-bg);
}

thead {
    background: var(--color-bg-subtle);
    border-bottom: 2px solid var(--color-border);
}

th {
    padding: var(--spacing) var(--spacing-md);
    text-align: left;
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-light);
}

td {
    padding: var(--spacing) var(--spacing-md);
    border-bottom: 1px solid var(--color-border-light);
    color: var(--color-text);
}

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

tbody tr:last-child td {
    border-bottom: none;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.15s ease;
    text-decoration: none;
    line-height: 1.5;
}

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

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

.btn-secondary {
    background: var(--color-bg);
    color: var(--color-text);
    border-color: var(--color-border);
}

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

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

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

.btn-link {
    background: none;
    border: none;
    color: var(--color-primary);
    padding: 0;
    text-decoration: underline;
}

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

.btn-icon {
    padding: 0.5rem;
    width: 32px;
    height: 32px;
    justify-content: center;
}

/* Actions */
.actions {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

.action-link {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.875rem;
}

.action-link:hover {
    text-decoration: underline;
}

.action-delete {
    color: var(--color-danger);
    background: none;
    border: none;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.875rem;
    padding: 0;
}

.action-delete:hover {
    text-decoration: underline;
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.5rem 0.75rem;
    font-size: 0.875rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    background: var(--color-bg);
    color: var(--color-text);
    transition: border-color 0.15s ease;
}

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

.form-helptext {
    font-size: 0.75rem;
    color: var(--color-text-light);
    margin-top: var(--spacing-xs);
}

.form-error {
    color: var(--color-danger);
    font-size: 0.75rem;
    margin-top: var(--spacing-xs);
}

.errorlist {
    color: var(--color-danger);
    list-style: none;
    padding: 0;
    margin: 0;
    font-size: 0.75rem;
}

/* Filter Form */
.filter-form {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing);
    align-items: flex-end;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

.filter-form .form-group {
    margin: 0;
    min-width: 150px;
}

.filter-form .form-input,
.filter-form .form-select {
    width: auto;
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing);
    margin-top: var(--spacing-lg);
    padding: var(--spacing);
}

.pagination a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
}

.pagination a:hover {
    text-decoration: underline;
}

.pagination .current {
    color: var(--color-text-light);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--color-text-light);
}

.empty-state h3 {
    margin: 0 0 var(--spacing-sm);
    color: var(--color-text);
}

/* Messages */
.messages {
    list-style: none;
    padding: 0;
    margin: 0 0 var(--spacing-lg);
}

.messages li {
    padding: var(--spacing) var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    border-radius: var(--radius);
    border: 1px solid;
}

.messages .success {
    background: #d1fae5;
    border-color: #a7f3d0;
    color: #065f46;
}

.messages .error {
    background: #fee2e2;
    border-color: #fecaca;
    color: #991b1b;
}

.messages .warning {
    background: #fef3c7;
    border-color: #fde68a;
    color: #92400e;
}

.messages .info {
    background: #dbeafe;
    border-color: #bfdbfe;
    color: #1e40af;
}

/* Modal */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

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

.modal-dialog {
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    max-width: 480px;
    width: 90%;
    box-shadow: var(--shadow-md);
}

.modal-dialog h2 {
    margin: 0 0 var(--spacing);
    font-size: 1.25rem;
}

.modal-dialog p {
    margin: 0 0 var(--spacing-lg);
    color: var(--color-text-light);
}

.modal-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
}

/* Dashboard */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.stat-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    text-align: center;
}

.stat-card h3 {
    margin: 0 0 var(--spacing-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-card .stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
}

.stat-card a {
    display: inline-block;
    margin-top: var(--spacing);
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.875rem;
}

.stat-card a:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: var(--spacing);
    }

    .nav {
        flex-wrap: wrap;
        justify-content: center;
    }

    .page-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing);
    }

    .filter-form {
        flex-direction: column;
        align-items: stretch;
    }

    .filter-form .form-group {
        min-width: 100%;
    }

    table {
        font-size: 0.875rem;
    }

    th, td {
        padding: var(--spacing-sm);
    }
}