/* ============================================
   EduFlow - School Management System Styles
   Design System: Alpine Frost + Indigo Ink
   ============================================ */

/* CSS Variables - Design Tokens */
:root {
    /* Primary Colors - Alpine Frost + Indigo Ink blend */
    --primary-50: #EEF2FF;
    --primary-100: #E0E7FF;
    --primary-200: #C7D2FE;
    --primary-300: #A5B4FC;
    --primary-400: #818CF8;
    --primary-500: #6366F1;
    --primary-600: #4F46E5;
    --primary-700: #4338CA;
    --primary-800: #3730A3;
    --primary-900: #312E81;
    
    /* Neutral Colors */
    --gray-50: #F8FAFC;
    --gray-100: #F1F5F9;
    --gray-200: #E2E8F0;
    --gray-300: #CBD5E1;
    --gray-400: #94A3B8;
    --gray-500: #64748B;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1E293B;
    --gray-900: #0F172A;
    
    /* Semantic Colors */
    --success-50: #F0FDF4;
    --success-100: #DCFCE7;
    --success-500: #22C55E;
    --success-600: #16A34A;
    --warning-50: #FFFBEB;
    --warning-100: #FEF3C7;
    --warning-500: #F59E0B;
    --warning-600: #D97706;
    --error-50: #FEF2F2;
    --error-100: #FEE2E2;
    --error-500: #EF4444;
    --error-600: #DC2626;
    
    /* Typography */
    --font-display: 'DM Serif Display', serif;
    --font-body: 'Plus Jakarta Sans', sans-serif;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Sidebar */
    --sidebar-width: 280px;
    --sidebar-collapsed: 80px;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    font-size: 0.9375rem;
    line-height: 1.6;
    color: var(--gray-800);
    background: var(--gray-50);
    min-height: 100vh;
}

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

/* ============================================
   SIDEBAR
   ============================================ */
.sidebar {
    width: var(--sidebar-width);
    background: linear-gradient(180deg, var(--gray-900) 0%, #1a1f36 100%);
    color: white;
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    z-index: 100;
    transition: width var(--transition-base);
    overflow: hidden;
}

.sidebar.collapsed {
    width: var(--sidebar-collapsed);
}

.sidebar-header {
    padding: var(--space-6);
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.logo-icon {
    font-size: 1.75rem;
    filter: drop-shadow(0 2px 4px rgba(99, 102, 241, 0.4));
}

.logo-text {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 400;
    background: linear-gradient(135deg, #fff 0%, var(--primary-300) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-toggle {
    background: rgba(255, 255, 255, 0.1);
    border: none;
    color: white;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-lg);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
}

.sidebar-nav {
    flex: 1;
    padding: var(--space-4);
    overflow-y: auto;
}

.nav-section {
    margin-bottom: var(--space-6);
}

.nav-label {
    display: block;
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--gray-400);
    padding: 0 var(--space-4);
    margin-bottom: var(--space-3);
}

.nav-list {
    list-style: none;
}

.nav-item {
    margin-bottom: var(--space-1);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
    color: var(--gray-300);
    text-decoration: none;
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.nav-link:hover {
    color: white;
    background: rgba(255, 255, 255, 0.08);
}

.nav-item.active .nav-link {
    color: white;
    background: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-700) 100%);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.4);
}

.nav-icon {
    flex-shrink: 0;
}

.sidebar-footer {
    padding: var(--space-4) var(--space-6);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.user-profile {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--primary-500) 0%, var(--primary-700) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.875rem;
    color: white;
    flex-shrink: 0;
}

.user-avatar.small {
    width: 32px;
    height: 32px;
    font-size: 0.75rem;
}

.user-avatar.large {
    width: 64px;
    height: 64px;
    font-size: 1.25rem;
}

.user-info {
    display: flex;
    flex-direction: column;
}

.user-name {
    font-weight: 600;
    font-size: 0.875rem;
    color: white;
}

.user-role {
    font-size: 0.75rem;
    color: var(--gray-400);
}

/* ============================================
   MAIN CONTENT
   ============================================ */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: margin-left var(--transition-base);
}

.sidebar.collapsed + .main-content {
    margin-left: var(--sidebar-collapsed);
}

/* Top Header */
.top-header {
    background: white;
    padding: var(--space-6) var(--space-8);
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--gray-200);
    position: sticky;
    top: 0;
    z-index: 50;
}

.header-left {
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.page-title {
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 400;
    color: var(--gray-900);
    line-height: 1.2;
}

.page-subtitle {
    font-size: 0.875rem;
    color: var(--gray-500);
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.search-box {
    position: relative;
    width: 320px;
}

.search-icon {
    position: absolute;
    left: var(--space-3);
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
}

.search-box input {
    width: 100%;
    padding: var(--space-3) var(--space-4) var(--space-3) var(--space-10);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    font-size: 0.875rem;
    background: var(--gray-50);
    transition: all var(--transition-fast);
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-300);
    background: white;
    box-shadow: 0 0 0 3px var(--primary-100);
}

.notification-btn {
    position: relative;
    width: 44px;
    height: 44px;
    border: none;
    background: var(--gray-50);
    border-radius: var(--radius-lg);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--gray-600);
    transition: all var(--transition-fast);
}

.notification-btn:hover {
    background: var(--gray-100);
    color: var(--gray-800);
}

.notification-badge {
    position: absolute;
    top: 6px;
    right: 6px;
    width: 18px;
    height: 18px;
    background: var(--error-500);
    color: white;
    font-size: 0.625rem;
    font-weight: 700;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--gray-50);
}

/* Page Content */
.page-content {
    flex: 1;
    padding: var(--space-8);
    overflow-y: auto;
}

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

.page.active {
    display: block;
}

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

/* ============================================
   DASHBOARD
   ============================================ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-6);
    margin-bottom: var(--space-8);
}

.stat-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    display: flex;
    align-items: flex-start;
    gap: var(--space-4);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    transition: all var(--transition-base);
}

.stat-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.stat-icon.students {
    background: var(--primary-50);
}

.stat-icon.teachers {
    background: var(--success-50);
}

.stat-icon.classes {
    background: var(--warning-50);
}

.stat-icon.attendance {
    background: #FDF2F8;
}

.stat-info {
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--gray-900);
    line-height: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--gray-500);
    font-weight: 500;
}

.stat-change {
    font-size: 0.75rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.stat-change.positive {
    color: var(--success-600);
}

.stat-change.negative {
    color: var(--error-600);
}

.stat-change.neutral {
    color: var(--gray-400);
}

.dashboard-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-6);
    margin-bottom: var(--space-6);
}

.dashboard-card {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    overflow: hidden;
}

.dashboard-card.full-width {
    grid-column: 1 / -1;
}

.card-header {
    padding: var(--space-5) var(--space-6);
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--gray-100);
}

.card-header h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-800);
}

.btn-text {
    background: none;
    border: none;
    color: var(--primary-600);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: color var(--transition-fast);
}

.btn-text:hover {
    color: var(--primary-700);
}

.activity-list {
    padding: var(--space-4);
}

.activity-item {
    display: flex;
    align-items: flex-start;
    gap: var(--space-4);
    padding: var(--space-4);
    border-radius: var(--radius-lg);
    transition: background var(--transition-fast);
}

.activity-item:hover {
    background: var(--gray-50);
}

.activity-avatar {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--primary-400) 0%, var(--primary-600) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: white;
    flex-shrink: 0;
}

.activity-content {
    flex: 1;
}

.activity-content p {
    font-size: 0.875rem;
    color: var(--gray-700);
    line-height: 1.5;
}

.activity-content strong {
    color: var(--gray-900);
    font-weight: 600;
}

.activity-time {
    font-size: 0.75rem;
    color: var(--gray-400);
    margin-top: var(--space-1);
    display: block;
}

.event-list {
    padding: var(--space-4);
}

.event-item {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-4);
    border-radius: var(--radius-lg);
    transition: background var(--transition-fast);
}

.event-item:hover {
    background: var(--gray-50);
}

.event-date {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--primary-500) 0%, var(--primary-700) 100%);
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: white;
    flex-shrink: 0;
}

.event-day {
    font-size: 1.25rem;
    font-weight: 700;
    line-height: 1;
}

.event-month {
    font-size: 0.625rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.event-content h4 {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: var(--space-1);
}

.event-content p {
    font-size: 0.8125rem;
    color: var(--gray-500);
}

.quick-actions {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: var(--space-4);
    padding: var(--space-6);
}

.action-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-6) var(--space-4);
    background: var(--gray-50);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.action-btn:hover {
    background: white;
    border-color: var(--primary-300);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.action-icon {
    font-size: 1.5rem;
}

.action-btn span:last-child {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--gray-700);
}

/* ============================================
   PAGE ACTIONS & FILTERS
   ============================================ */
.page-actions {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-6);
}

.filters {
    display: flex;
    gap: var(--space-3);
}

.filter-select {
    padding: var(--space-3) var(--space-4);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    color: var(--gray-700);
    background: white;
    cursor: pointer;
    min-width: 160px;
    transition: all var(--transition-fast);
}

.filter-select:focus {
    outline: none;
    border-color: var(--primary-300);
    box-shadow: 0 0 0 3px var(--primary-100);
}

/* Buttons */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    background: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-700) 100%);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(79, 70, 229, 0.4);
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-4);
    background: white;
    color: var(--gray-700);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-secondary:hover {
    background: var(--gray-50);
    border-color: var(--gray-300);
}

.btn-icon {
    width: 36px;
    height: 36px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.btn-icon:hover {
    background: var(--gray-100);
}

/* ============================================
   DATA TABLES
   ============================================ */
.data-table-container {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    overflow: hidden;
}

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

.data-table th {
    background: var(--gray-50);
    padding: var(--space-4) var(--space-5);
    text-align: left;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--gray-500);
    border-bottom: 1px solid var(--gray-200);
}

.data-table td {
    padding: var(--space-4) var(--space-5);
    border-bottom: 1px solid var(--gray-100);
    font-size: 0.875rem;
    color: var(--gray-700);
}

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

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

.user-cell {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.status-badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
}

.status-badge.active {
    background: var(--success-50);
    color: var(--success-600);
}

.status-badge.inactive {
    background: var(--gray-100);
    color: var(--gray-500);
}

/* Pagination */
.pagination {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-4);
    margin-top: var(--space-6);
}

.btn-page {
    padding: var(--space-3) var(--space-4);
    background: white;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--gray-700);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-page:hover:not(:disabled) {
    background: var(--gray-50);
    border-color: var(--gray-300);
}

.btn-page:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.page-numbers {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.page-num {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: white;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--gray-700);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.page-num:hover:not(.active) {
    background: var(--gray-50);
}

.page-num.active {
    background: var(--primary-600);
    border-color: var(--primary-600);
    color: white;
}

/* ============================================
   TEACHER CARDS
   ============================================ */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-6);
}

.teacher-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    transition: all var(--transition-base);
}

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

.teacher-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--space-4);
}

.teacher-status {
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.teacher-status.active {
    background: var(--success-50);
    color: var(--success-600);
}

.teacher-status.on-leave {
    background: var(--warning-50);
    color: var(--warning-600);
}

.teacher-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: var(--space-1);
}

.teacher-subject {
    font-size: 0.875rem;
    color: var(--gray-500);
    margin-bottom: var(--space-5);
}

.teacher-stats {
    display: flex;
    gap: var(--space-8);
    padding: var(--space-4) 0;
    border-top: 1px solid var(--gray-100);
    border-bottom: 1px solid var(--gray-100);
    margin-bottom: var(--space-5);
}

.teacher-stats > div {
    display: flex;
    flex-direction: column;
}

.stat-num {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--gray-800);
}

.teacher-actions {
    display: flex;
    gap: var(--space-3);
}

/* ============================================
   CLASS CARDS
   ============================================ */
.classes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--space-6);
}

.class-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    transition: all var(--transition-base);
}

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

.class-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-4);
}

.class-grade {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--primary-600);
    background: var(--primary-50);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
}

.class-code {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--gray-400);
    font-family: monospace;
}

.class-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: var(--space-2);
}

.class-teacher {
    font-size: 0.875rem;
    color: var(--gray-500);
    margin-bottom: var(--space-4);
}

.class-meta {
    display: flex;
    gap: var(--space-4);
    margin-bottom: var(--space-5);
}

.class-meta span {
    font-size: 0.8125rem;
    color: var(--gray-500);
}

.class-progress {
    margin-bottom: var(--space-5);
}

.progress-header {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--gray-500);
    margin-bottom: var(--space-2);
}

.progress-bar {
    height: 6px;
    background: var(--gray-100);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-500) 0%, var(--primary-600) 100%);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
}

.progress-fill.full {
    background: var(--error-500);
}

.class-actions {
    display: flex;
    gap: var(--space-3);
}

/* ============================================
   ATTENDANCE
   ============================================ */
.attendance-container {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    overflow: hidden;
}

.attendance-summary {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
    border-bottom: 1px solid var(--gray-100);
}

.summary-item {
    padding: var(--space-6);
    text-align: center;
    border-right: 1px solid var(--gray-100);
}

.summary-item:last-child {
    border-right: none;
}

.summary-value {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--gray-800);
    line-height: 1;
    margin-bottom: var(--space-2);
}

.summary-label {
    font-size: 0.875rem;
    color: var(--gray-500);
    font-weight: 500;
}

.attendance-toggle {
    display: flex;
    gap: var(--space-2);
}

.att-btn {
    width: 36px;
    height: 36px;
    border: 2px solid var(--gray-200);
    background: white;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 700;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.att-btn:hover {
    border-color: var(--gray-300);
}

.att-btn.present {
    color: var(--success-600);
}

.att-btn.present.active {
    background: var(--success-500);
    border-color: var(--success-500);
    color: white;
}

.att-btn.absent {
    color: var(--error-600);
}

.att-btn.absent.active {
    background: var(--error-500);
    border-color: var(--error-500);
    color: white;
}

.att-btn.late {
    color: var(--warning-600);
}

.att-btn.late.active {
    background: var(--warning-500);
    border-color: var(--warning-500);
    color: white;
}

.remark-input {
    width: 100%;
    padding: var(--space-2) var(--space-3);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

.remark-input:focus {
    outline: none;
    border-color: var(--primary-300);
}

/* ============================================
   GRADES
   ============================================ */
.grades-overview {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-6);
    margin-bottom: var(--space-6);
}

.grade-stat-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    text-align: center;
}

.grade-stat-card h4 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--gray-500);
    margin-bottom: var(--space-3);
}

.grade-value {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--gray-800);
    line-height: 1;
    margin-bottom: var(--space-2);
}

.grade-trend {
    font-size: 0.875rem;
    font-weight: 600;
}

.grade-trend.positive {
    color: var(--success-600);
}

.grade-student {
    font-size: 0.8125rem;
    color: var(--gray-500);
}

.rank-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
}

.rank-badge.gold {
    background: linear-gradient(135deg, #FFD700 0%, #FFA500 100%);
    color: white;
}

.rank-badge.silver {
    background: linear-gradient(135deg, #C0C0C0 0%, #A0A0A0 100%);
    color: white;
}

.rank-badge.bronze {
    background: linear-gradient(135deg, #CD7F32 0%, #B87333 100%);
    color: white;
}

.grade-badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
}

.grade-badge.a {
    background: var(--success-50);
    color: var(--success-600);
}

.grade-badge.b {
    background: var(--primary-50);
    color: var(--primary-600);
}

.grade-badge.c {
    background: var(--warning-50);
    color: var(--warning-600);
}

.grade-badge.d {
    background: var(--error-50);
    color: var(--error-600);
}

/* ============================================
   MODAL
   ============================================ */
.modal {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.5);
    z-index: 200;
    align-items: center;
    justify-content: center;
    padding: var(--space-6);
    backdrop-filter: blur(4px);
}

.modal.active {
    display: flex;
}

.modal-content {
    background: white;
    border-radius: var(--radius-2xl);
    width: 100%;
    max-width: 560px;
    max-height: calc(100vh - var(--space-12));
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-6);
    border-bottom: 1px solid var(--gray-100);
}

.modal-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--gray-800);
}

.modal-close {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gray-100);
    border: none;
    border-radius: var(--radius-lg);
    font-size: 1.5rem;
    color: var(--gray-500);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--gray-200);
    color: var(--gray-700);
}

.modal-form {
    padding: var(--space-6);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--gray-700);
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: var(--space-3) var(--space-4);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    color: var(--gray-800);
    transition: all var(--transition-fast);
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-300);
    box-shadow: 0 0 0 3px var(--primary-100);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
    margin-top: var(--space-6);
    padding-top: var(--space-6);
    border-top: 1px solid var(--gray-100);
}

/* ============================================
   PLACEHOLDER PAGES
   ============================================ */
.placeholder-page {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-16);
    text-align: center;
}

.placeholder-icon {
    font-size: 4rem;
    margin-bottom: var(--space-6);
    opacity: 0.5;
}

.placeholder-page h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--gray-700);
    margin-bottom: var(--space-3);
}

.placeholder-page p {
    color: var(--gray-500);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 1280px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .quick-actions {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .grades-overview {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .sidebar.collapsed + .main-content {
        margin-left: 0;
    }
    
    .search-box {
        width: 240px;
    }
}

@media (max-width: 768px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .quick-actions {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grades-overview {
        grid-template-columns: 1fr;
    }
    
    .attendance-summary {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .summary-item:nth-child(2) {
        border-right: none;
    }
    
    .summary-item:nth-child(1),
    .summary-item:nth-child(2) {
        border-bottom: 1px solid var(--gray-100);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .top-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-4);
    }
    
    .header-right {
        width: 100%;
    }
    
    .search-box {
        flex: 1;
    }
}

@media (max-width: 640px) {
    .page-content {
        padding: var(--space-4);
    }
    
    .quick-actions {
        grid-template-columns: 1fr;
    }
    
    .data-table-container {
        overflow-x: auto;
    }
    
    .data-table {
        min-width: 800px;
    }
}

/* ============================================
   ANIMATIONS & UTILITIES
   ============================================ */
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.animate-pulse {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--gray-100);
}

::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--gray-400);
}

/* Selection */
::selection {
    background: var(--primary-200);
    color: var(--primary-900);
}