/* 
 * CyberSomo Smart School Management System
 * Custom Design System & CSS3 Architecture (No external UI frameworks)
 * 8-Point Grid, Premium Dark Mode Default, Accessible Contrast, Fluid Layout
 * STRICTLY NO EMOJIS
 */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
    /* 8-Point Grid Spacing Units */
    --space-1: 8px;
    --space-2: 16px;
    --space-3: 24px;
    --space-4: 32px;
    --space-6: 48px;
    --space-8: 64px;

    /* Color Palette - Premium Dark Theme */
    --bg-base: #0B0F19;
    --bg-surface: #0F172A;
    --bg-card: #1E293B;
    --bg-card-hover: #243248;
    --bg-input: #0F172A;
    --bg-overlay: rgba(11, 15, 25, 0.75);

    /* Borders */
    --border-subtle: rgba(255, 255, 255, 0.08);
    --border-card: rgba(255, 255, 255, 0.12);
    --border-focus: #38BDF8;

    /* Typography Colors */
    --text-primary: #F8FAFC;
    --text-secondary: #94A3B8;
    --text-muted: #64748B;
    --text-inverse: #0F172A;

    /* Semantic Accents */
    --primary: #38BDF8;
    --primary-hover: #0EA5E9;
    --primary-light: rgba(56, 189, 248, 0.15);
    
    --success: #10B981;
    --success-hover: #059669;
    --success-bg: rgba(16, 185, 129, 0.12);
    --success-border: rgba(16, 185, 129, 0.3);

    --danger: #EF4444;
    --danger-hover: #DC2626;
    --danger-bg: rgba(239, 68, 68, 0.12);
    --danger-border: rgba(239, 68, 68, 0.3);

    --warning: #F59E0B;
    --warning-hover: #D97706;
    --warning-bg: rgba(245, 158, 11, 0.12);
    --warning-border: rgba(245, 158, 11, 0.3);

    --info: #6366F1;
    --info-bg: rgba(99, 102, 241, 0.12);

    /* Layout Metrics */
    --sidebar-width: 260px;
    --sidebar-collapsed-width: 72px;
    --header-height: 64px;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-full: 9999px;

    /* Transitions & Shadows */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 250ms ease-in-out;
    --shadow-card: 0 4px 20px -2px rgba(0, 0, 0, 0.5);
    --shadow-dropdown: 0 10px 30px -5px rgba(0, 0, 0, 0.6);
}

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

html, body {
    width: 100%;
    height: 100%;
    background-color: var(--bg-base);
    color: var(--text-primary);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

h1 { font-size: 28px; }
h2 { font-size: 22px; }
h3 { font-size: 18px; }
h4 { font-size: 16px; }

p {
    line-height: 1.6;
    color: var(--text-secondary);
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

code, pre {
    font-family: 'JetBrains Mono', monospace;
    font-size: 13px;
}

/* Focus States & Accessibility */
:focus-visible {
    outline: 2px solid var(--border-focus);
    outline-offset: 2px;
}

/* App Master Shell (Grid/Flex Fluid Viewport) */
.app-shell {
    display: flex;
    width: 100%;
    min-height: 100vh;
    background-color: var(--bg-base);
    overflow-x: hidden;
}

/* Sidebar Navigation */
.app-sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    background-color: var(--bg-surface);
    border-right: 1px solid var(--border-subtle);
    display: flex;
    flex-direction: column;
    height: 100vh;
    position: sticky;
    top: 0;
    z-index: 40;
    transition: width var(--transition-normal), min-width var(--transition-normal);
}

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

.sidebar-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-2);
    border-bottom: 1px solid var(--border-subtle);
}

.brand-logo {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-weight: 700;
    font-size: 16px;
    color: var(--text-primary);
    text-decoration: none;
    overflow: hidden;
    white-space: nowrap;
}

.brand-icon {
    width: 36px;
    height: 36px;
    min-width: 36px;
    background: linear-gradient(135deg, #38BDF8 0%, #6366F1 100%);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #FFFFFF;
    font-weight: 700;
    font-size: 18px;
}

.brand-text {
    transition: opacity var(--transition-fast);
}

.app-sidebar.collapsed .brand-text {
    display: none;
}

.sidebar-nav {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-2) var(--space-1);
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.nav-section-title {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    padding: var(--space-2) var(--space-2) var(--space-1) var(--space-2);
    white-space: nowrap;
    overflow: hidden;
}

.app-sidebar.collapsed .nav-section-title {
    display: none;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: 10px var(--space-2);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 13.5px;
    min-height: 44px;
    transition: all var(--transition-fast);
    white-space: nowrap;
    position: relative;
}

.nav-item:hover {
    background-color: rgba(255, 255, 255, 0.04);
    color: var(--text-primary);
}

.nav-item.active {
    background-color: var(--primary-light);
    color: var(--primary);
    font-weight: 600;
}

.nav-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 8px;
    bottom: 8px;
    width: 3px;
    background-color: var(--primary);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.nav-icon {
    width: 20px;
    height: 20px;
    min-width: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-icon svg {
    width: 18px;
    height: 18px;
    stroke-width: 2;
}

.app-sidebar.collapsed .nav-item {
    justify-content: center;
    padding: 10px 0;
}

.app-sidebar.collapsed .nav-label {
    display: none;
}

.sidebar-footer {
    padding: var(--space-2);
    border-top: 1px solid var(--border-subtle);
}

/* Main Content Area */
.app-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    width: 100%;
}

/* Top App Header */
.app-header {
    height: var(--header-height);
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-subtle);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-3);
    position: sticky;
    top: 0;
    z-index: 30;
}

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

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

.btn-icon {
    width: 44px;
    height: 44px;
    min-width: 44px;
    border-radius: var(--radius-sm);
    background-color: transparent;
    border: 1px solid transparent;
    color: var(--text-secondary);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-icon:hover {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border-color: var(--border-subtle);
}

.user-profile-badge {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: 6px var(--space-2);
    background-color: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    cursor: pointer;
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background-color: var(--primary);
    color: var(--text-inverse);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 13px;
}

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

.user-meta-name {
    font-weight: 600;
    font-size: 13px;
    color: var(--text-primary);
    line-height: 1.2;
}

.user-meta-role {
    font-size: 11px;
    color: var(--text-muted);
}

/* Dynamic Page Container */
.page-container {
    flex: 1;
    padding: var(--space-4);
    width: 100%;
}

.page-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-3);
    flex-wrap: wrap;
    gap: var(--space-2);
}

.page-title-wrap {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.page-subtitle {
    font-size: 13.5px;
    color: var(--text-muted);
}

/* Grid System */
.grid-1 { display: grid; grid-template-columns: 1fr; gap: var(--space-3); }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-3); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-3); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-3); }

/* Stats Card Component */
.stat-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    padding: var(--space-3);
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
    box-shadow: var(--shadow-card);
    transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.stat-card:hover {
    transform: translateY(-2px);
    border-color: rgba(255, 255, 255, 0.2);
}

.stat-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: var(--text-muted);
    font-size: 12.5px;
    font-weight: 500;
}

.stat-icon {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-value {
    font-size: 26px;
    font-weight: 700;
    color: var(--text-primary);
    margin-top: 4px;
}

.stat-footer {
    font-size: 12px;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 6px;
}

/* Card Component */
.card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-card);
    overflow: hidden;
    margin-bottom: var(--space-3);
}

.card-header {
    padding: var(--space-3);
    border-bottom: 1px solid var(--border-subtle);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-2);
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.card-body {
    padding: var(--space-3);
}

.card-footer {
    padding: var(--space-2) var(--space-3);
    border-top: 1px solid var(--border-subtle);
    background-color: rgba(0, 0, 0, 0.15);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* Modern Data Table */
.table-responsive {
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
    font-size: 13.5px;
}

.table th {
    background-color: rgba(15, 23, 42, 0.6);
    color: var(--text-secondary);
    font-weight: 600;
    padding: 12px var(--space-2);
    border-bottom: 1px solid var(--border-subtle);
    white-space: nowrap;
    text-transform: uppercase;
    font-size: 11px;
    letter-spacing: 0.05em;
}

.table td {
    padding: 14px var(--space-2);
    border-bottom: 1px solid var(--border-subtle);
    color: var(--text-primary);
    vertical-align: middle;
}

.table tbody tr {
    transition: background-color var(--transition-fast);
}

.table tbody tr:hover {
    background-color: rgba(255, 255, 255, 0.025);
}

/* Badges & Status Pills */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 10px;
    border-radius: var(--radius-full);
    font-size: 11.5px;
    font-weight: 600;
    line-height: 1;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.badge-success {
    background-color: var(--success-bg);
    color: var(--success);
    border: 1px solid var(--success-border);
}

.badge-danger {
    background-color: var(--danger-bg);
    color: var(--danger);
    border: 1px solid var(--danger-border);
}

.badge-warning {
    background-color: var(--warning-bg);
    color: var(--warning);
    border: 1px solid var(--warning-border);
}

.badge-info {
    background-color: var(--info-bg);
    color: var(--primary);
    border: 1px solid rgba(56, 189, 248, 0.3);
}

.badge-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background-color: currentColor;
}

/* Buttons System (44px Minimum Touch Target) */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-1);
    min-height: 44px;
    padding: 0 var(--space-3);
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 13.5px;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all var(--transition-fast);
    white-space: nowrap;
    text-decoration: none;
}

.btn-primary {
    background-color: var(--primary);
    color: var(--text-inverse);
    font-weight: 600;
}

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

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.06);
    color: var(--text-primary);
    border-color: var(--border-card);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.12);
}

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

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

.btn-sm {
    min-height: 36px;
    padding: 0 var(--space-2);
    font-size: 12.5px;
}

/* Form Controls & Inputs */
.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: var(--space-2);
}

.form-label {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-control {
    width: 100%;
    min-height: 44px;
    padding: 0 var(--space-2);
    background-color: var(--bg-input);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 14px;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control:focus {
    border-color: var(--primary);
    outline: none;
    box-shadow: 0 0 0 2px var(--primary-light);
}

textarea.form-control {
    padding: var(--space-1) var(--space-2);
    min-height: 96px;
}

select.form-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2394A3B8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

.form-error-text {
    font-size: 12px;
    color: var(--danger);
}

/* Alert Notification Boxes */
.alert {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    font-size: 13.5px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-2);
    margin-bottom: var(--space-3);
}

.alert-success {
    background-color: var(--success-bg);
    border: 1px solid var(--success-border);
    color: #34D399;
}

.alert-danger {
    background-color: var(--danger-bg);
    border: 1px solid var(--danger-border);
    color: #F87171;
}

.alert-warning {
    background-color: var(--warning-bg);
    border: 1px solid var(--warning-border);
    color: #FBBF24;
}

/* Modal Window System */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: var(--bg-overlay);
    backdrop-filter: blur(4px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 100;
    padding: var(--space-2);
}

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

.modal-dialog {
    background-color: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-md);
    width: 100%;
    max-width: 580px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-dropdown);
    animation: modalSlideIn 150ms ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-16px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.modal-header {
    padding: var(--space-3);
    border-bottom: 1px solid var(--border-subtle);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-body {
    padding: var(--space-3);
}

.modal-footer {
    padding: var(--space-2) var(--space-3);
    border-top: 1px solid var(--border-subtle);
    display: flex;
    justify-content: flex-end;
    gap: var(--space-2);
}

/* Skeleton Loader State */
.skeleton {
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.04) 25%, rgba(255, 255, 255, 0.08) 50%, rgba(255, 255, 255, 0.04) 75%);
    background-size: 200% 100%;
    animation: skeletonLoading 1.5s infinite;
    border-radius: var(--radius-sm);
}

@keyframes skeletonLoading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* Empty State Card */
.empty-state {
    padding: var(--space-6) var(--space-3);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    gap: var(--space-2);
}

.empty-state-icon {
    width: 64px;
    height: 64px;
    border-radius: var(--radius-full);
    background-color: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-subtle);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
}

/* Toast Container */
.toast-container {
    position: fixed;
    bottom: var(--space-3);
    right: var(--space-3);
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
    z-index: 200;
}

.toast {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-sm);
    padding: 12px var(--space-2);
    min-width: 280px;
    max-width: 400px;
    box-shadow: var(--shadow-dropdown);
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: var(--space-2);
    animation: toastSlideIn 200ms ease-out;
}

@keyframes toastSlideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

/* Mobile Drawer Overlay Backdrop */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: var(--bg-overlay);
    z-index: 35;
}

/* Pagination Bar */
.pagination {
    display: flex;
    align-items: center;
    gap: 6px;
    list-style: none;
}

.page-item {
    display: inline-block;
}

.page-link {
    min-width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 10px;
    background-color: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 12.5px;
    font-weight: 500;
}

.page-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

.page-item.active .page-link {
    background-color: var(--primary);
    color: var(--text-inverse);
    font-weight: 700;
    border-color: var(--primary);
}

.page-item.disabled .page-link {
    opacity: 0.4;
    pointer-events: none;
}

/* Responsive Breakpoints & Mobile Drawer */
@media (max-width: 1024px) {
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .app-sidebar {
        position: fixed;
        left: -100%;
        top: 0;
        bottom: 0;
        z-index: 50;
        width: 280px;
        min-width: 280px;
        transition: left var(--transition-normal);
    }

    .app-sidebar.mobile-open {
        left: 0;
    }

    .sidebar-overlay.active {
        display: block;
    }

    .grid-4, .grid-3, .grid-2 {
        grid-template-columns: 1fr;
    }

    .page-container {
        padding: var(--space-2);
    }
}