/* ========================
   Global Styles & Reset
======================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Primary Colors */
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #3b82f6;
    
    /* Status Colors */
    --success: #10b981;
    --success-dark: #059669;
    --warning: #f59e0b;
    --warning-dark: #d97706;
    --danger: #ef4444;
    --danger-dark: #dc2626;
    --info: #3b82f6;
    
    /* Neutral Colors */
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* Additional Colors */
    --purple: #8b5cf6;
    --orange: #f97316;
    --blue: #2563eb;
    --green: #10b981;
    
    /* Backgrounds */
    --bg-main: #f5f7fa;
    --bg-white: #ffffff;
    --bg-dark: #1f2937;
    
    /* Shadows */
    --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);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition: all 0.3s ease;
    
    /* Layout */
    --navbar-height: 60px;
    --sidebar-width: 250px;
}

body {
    font-family: 'Sarabun', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-main);
    color: var(--gray-800);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ========================
   Navigation Bar
======================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    background: var(--bg-white);
    box-shadow: var(--shadow-md);
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
    padding: 0 2rem;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
}

.nav-brand i {
    font-size: 1.5rem;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--gray-600);
}

.nav-info i {
    font-size: 1.5rem;
}

/* ========================
   App Container & Layout
======================== */
.app-container {
    display: flex;
    margin-top: var(--navbar-height);
    min-height: calc(100vh - var(--navbar-height));
}

/* ========================
   Sidebar
======================== */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-white);
    box-shadow: var(--shadow-md);
    position: fixed;
    left: 0;
    top: var(--navbar-height);
    bottom: 0;
    overflow-y: auto;
    transition: var(--transition);
}

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

.menu-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.875rem 1.5rem;
    color: var(--gray-700);
    text-decoration: none;
    transition: var(--transition);
    border-left: 3px solid transparent;
}

.menu-item:hover {
    background: var(--gray-50);
    color: var(--primary);
}

.menu-item.active {
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    border-left-color: var(--primary);
    font-weight: 600;
}

.menu-item i {
    font-size: 1.25rem;
    width: 24px;
    text-align: center;
}

/* ========================
   Main Content
======================== */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 2rem;
    transition: var(--transition);
}

.page {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

.page.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================
   Page Header
======================== */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.page-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--gray-900);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.page-header p {
    color: var(--gray-600);
    margin-top: 0.25rem;
}

/* ========================
   Cards
======================== */
.card {
    background: var(--bg-white);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.card-header h3 {
    margin-bottom: 0;
}

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

.stat-card {
    background: var(--bg-white);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
}

.stat-card.blue .stat-icon {
    background: rgba(37, 99, 235, 0.1);
    color: var(--blue);
}

.stat-card.green .stat-icon {
    background: rgba(16, 185, 129, 0.1);
    color: var(--green);
}

.stat-card.orange .stat-icon {
    background: rgba(249, 115, 22, 0.1);
    color: var(--orange);
}

.stat-card.purple .stat-icon {
    background: rgba(139, 92, 246, 0.1);
    color: var(--purple);
}

.stat-content {
    flex: 1;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--gray-900);
}

.stat-label {
    color: var(--gray-600);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

/* ========================
   Charts
======================== */
.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.chart-card {
    background: var(--bg-white);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 1.5rem;
}

.chart-container {
    position: relative;
    width: 100%;
}

/* ========================
   Forms
======================== */
.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-weight: 500;
    color: var(--gray-700);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 1px solid var(--gray-300);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
}

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

.form-group textarea {
    resize: vertical;
}

/* ========================
   Buttons
======================== */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition);
    text-decoration: none;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

.btn-success:hover:not(:disabled) {
    background: var(--success-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

.btn-danger:hover:not(:disabled) {
    background: var(--danger-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

.btn-warning:hover:not(:disabled) {
    background: var(--warning-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--gray-200);
    color: var(--gray-700);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--gray-300);
}

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

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

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

.data-table thead {
    background: var(--gray-50);
}

.data-table th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: var(--gray-700);
    border-bottom: 2px solid var(--gray-200);
}

.data-table td {
    padding: 1rem;
    border-bottom: 1px solid var(--gray-200);
}

.data-table tbody tr {
    transition: var(--transition);
}

.data-table tbody tr:hover {
    background: var(--gray-50);
}

.table-actions {
    display: flex;
    gap: 0.5rem;
}

/* ========================
   Attendance List
======================== */
.attendance-list {
    display: grid;
    gap: 1rem;
}

.attendance-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background: var(--gray-50);
    border-radius: 8px;
    gap: 1rem;
}

.student-photo {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    object-fit: cover;
    background: var(--gray-300);
}

.student-info {
    flex: 1;
}

.student-name {
    font-weight: 600;
    color: var(--gray-800);
}

.student-code {
    color: var(--gray-600);
    font-size: 0.875rem;
}

.attendance-status {
    display: flex;
    gap: 0.5rem;
}

.status-btn {
    padding: 0.5rem 1rem;
    border: 2px solid var(--gray-300);
    background: white;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.status-btn.active.present {
    background: var(--success);
    border-color: var(--success);
    color: white;
}

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

.status-btn.active.late {
    background: var(--warning);
    border-color: var(--warning);
    color: white;
}

.status-btn.active.leave {
    background: var(--info);
    border-color: var(--info);
    color: white;
}

/* ========================
   Report Content
======================== */
.report-content {
    overflow-x: auto;
}

.report-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.summary-item {
    padding: 1rem;
    background: var(--gray-50);
    border-radius: 8px;
    text-align: center;
}

.summary-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--gray-900);
}

.summary-label {
    color: var(--gray-600);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.report-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.report-table th,
.report-table td {
    padding: 0.75rem;
    text-align: left;
    border: 1px solid var(--gray-200);
}

.report-table th {
    background: var(--gray-100);
    font-weight: 600;
}

.report-table .pass {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-dark);
    font-weight: 600;
}

.report-table .fail {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-dark);
    font-weight: 600;
}

/* ========================
   Low Attendance List
======================== */
.low-attendance-list {
    display: grid;
    gap: 1rem;
}

.low-attendance-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background: rgba(239, 68, 68, 0.05);
    border-left: 4px solid var(--danger);
    border-radius: 8px;
    gap: 1rem;
}

.low-attendance-item .student-photo {
    width: 50px;
    height: 50px;
}

.low-attendance-info {
    flex: 1;
}

.low-attendance-percentage {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--danger);
}

/* ========================
   Modal
======================== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 2000;
    animation: fadeIn 0.3s ease;
}

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

.modal-content {
    background: var(--bg-white);
    border-radius: 12px;
    box-shadow: var(--shadow-xl);
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--gray-200);
}

.modal-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.modal-close {
    font-size: 2rem;
    background: none;
    border: none;
    color: var(--gray-500);
    cursor: pointer;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    transition: var(--transition);
}

.modal-close:hover {
    background: var(--gray-100);
    color: var(--gray-700);
}

.modal-body {
    padding: 1.5rem;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    padding: 1.5rem;
    border-top: 1px solid var(--gray-200);
}

/* ========================
   Toast Notification
======================== */
.toast {
    position: fixed;
    top: calc(var(--navbar-height) + 1rem);
    right: 1rem;
    background: var(--gray-900);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow-lg);
    z-index: 3000;
    transform: translateX(400px);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    min-width: 300px;
}

.toast.show {
    transform: translateX(0);
}

.toast.success {
    background: var(--success);
}

.toast.error {
    background: var(--danger);
}

.toast.warning {
    background: var(--warning);
}

.toast.info {
    background: var(--info);
}

/* ========================
   Badges
======================== */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.875rem;
    font-weight: 500;
}

.badge.success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-dark);
}

.badge.danger {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-dark);
}

.badge.warning {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-dark);
}

.badge.info {
    background: rgba(59, 130, 246, 0.1);
    color: var(--info);
}

/* ========================
   Loading State
======================== */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    color: var(--gray-500);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--gray-200);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* ========================
   Empty State
======================== */
.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--gray-500);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    color: var(--gray-400);
}

.empty-state h3 {
    font-size: 1.25rem;
    color: var(--gray-700);
    margin-bottom: 0.5rem;
}

/* ========================
   Responsive Design
======================== */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .sidebar.active {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-container {
        padding: 0 1rem;
    }
    
    .main-content {
        padding: 1rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .page-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .attendance-item {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .attendance-status {
        width: 100%;
        flex-wrap: wrap;
    }
    
    .status-btn {
        flex: 1;
    }
    
    .modal-content {
        width: 95%;
    }
}

@media (max-width: 480px) {
    .nav-brand span {
        display: none;
    }
    
    .nav-info span {
        display: none;
    }
    
    .btn {
        padding: 0.625rem 1rem;
        font-size: 0.875rem;
    }
    
    .stat-card {
        flex-direction: column;
        text-align: center;
    }
}

/* ========================
   Print Styles
======================== */
@media print {
    .navbar,
    .sidebar,
    .page-header button,
    .card-header button,
    .table-actions,
    .modal,
    .toast {
        display: none !important;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid var(--gray-300);
        page-break-inside: avoid;
    }
}