/* ========================================
   MathGame Admin - Premium Design System
   ======================================== */

/* ==================
   CSS Custom Properties (Design Tokens)
   ================== */
:root {
    /* Color Palette - Light Theme */
    --bg-primary: #f8f9fa;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e9ecef;

    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --text-tertiary: #718096;
    --text-inverse: #ffffff;

    --brand-primary: #6366f1;
    --brand-secondary: #8b5cf6;
    --brand-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --brand-gradient-alt: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);

    --accent-success: #10b981;
    --accent-warning: #f59e0b;
    --accent-danger: #ef4444;
    --accent-info: #3b82f6;

    --border-color: #e2e8f0;
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --border-radius-lg: 16px;

    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);

    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.18);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.15);

    --sidebar-width: 280px;
    --navbar-height: 70px;

    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;

    --font-family-base: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-family-heading: 'Outfit', 'Inter', sans-serif;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;

    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #94a3b8;
    --text-inverse: #0f172a;

    --border-color: #334155;

    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
}

/* ==================
   Base Styles
   ================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family-base);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    transition: background-color var(--transition-base);
    overflow-x: hidden;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-family-heading);
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
}

/* ==================
   Animated Background
   ================== */
.animated-bg {
    background: linear-gradient(-45deg, #667eea, #764ba2, #f093fb, #f5576c);
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
}

@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

/* ==================
   Layout
   ================== */
.wrapper {
    display: flex;
    min-height: 100vh;
}

.content {
    margin-left: var(--sidebar-width);
    flex: 1;
    min-height: 100vh;
    background: var(--bg-primary);
    transition: margin-left var(--transition-base);
}

.main-content {
    padding: 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

/* ==================
   Sidebar
   ================== */
.sidebar {
    width: var(--sidebar-width);
    height: 100vh;
    position: fixed;
    top: 0;
    left: 0;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    z-index: 1000;
    overflow-y: auto;
    transition: transform var(--transition-base);
}

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

.sidebar-title {
    color: var(--text-inverse);
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0;
    text-align: center;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.sidebar-nav {
    list-style: none;
    padding: 1rem 0;
}

.sidebar-nav .nav-item {
    margin: 0.25rem 0.75rem;
}

.sidebar-nav .nav-link {
    display: flex;
    align-items: center;
    padding: 0.875rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-base);
    font-weight: 500;
    position: relative;
    overflow: hidden;
}

.sidebar-nav .nav-link::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 4px;
    background: var(--brand-gradient);
    transform: scaleY(0);
    transition: transform var(--transition-base);
}

.sidebar-nav .nav-link:hover {
    background: var(--bg-tertiary);
    color: var(--brand-primary);
    transform: translateX(4px);
}

.sidebar-nav .nav-link:hover::before {
    transform: scaleY(1);
}

.sidebar-nav .nav-item.active .nav-link {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
    color: var(--brand-primary);
    font-weight: 600;
}

.sidebar-nav .nav-item.active .nav-link::before {
    transform: scaleY(1);
}

.sidebar-nav .nav-link i {
    margin-right: 0.75rem;
    width: 20px;
    text-align: center;
    font-size: 1.1rem;
    transition: transform var(--transition-base);
}

.sidebar-nav .nav-link:hover i {
    transform: scale(1.2);
}

.sidebar-divider {
    margin: 1rem 1.5rem;
    border: none;
    border-top: 1px solid var(--border-color);
}

/* ==================
   Navbar
   ================== */
.navbar {
    height: var(--navbar-height);
    background: var(--bg-secondary) !important;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    padding: 0 2rem !important;
}

.navbar-brand {
    font-family: var(--font-family-heading);
    font-weight: 700;
    color: var(--text-primary) !important;
    font-size: 1.25rem;
}

.navbar-nav .nav-link {
    color: var(--text-secondary) !important;
    padding: 0.5rem 1rem !important;
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
}

.navbar-nav .nav-link:hover {
    color: var(--brand-primary) !important;
    background: var(--bg-tertiary);
}

/* Theme Toggle Button */
.theme-toggle {
    background: var(--bg-tertiary);
    border: none;
    padding: 0.5rem 0.75rem;
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-base);
}

.theme-toggle:hover {
    background: var(--brand-primary);
    color: var(--text-inverse);
    transform: rotate(180deg);
}

/* ==================
   Cards
   ================== */
.card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    box-shadow: var(--glass-shadow);
    margin-bottom: 1.5rem;
    transition: all var(--transition-base);
}

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

.card-header {
    background: transparent;
    border-bottom: 1px solid var(--border-color);
    padding: 1.25rem 1.5rem;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
}

.card-title {
    color: var(--text-primary);
    font-weight: 600;
    margin: 0;
    font-size: 1.125rem;
}

.card-body {
    padding: 1.5rem;
}

/* Stat Cards with 3D Effect */
.stat-card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--brand-gradient);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-8px) rotateX(5deg);
    box-shadow: var(--shadow-xl);
}

.stat-card:hover::before {
    opacity: 0.05;
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    margin-bottom: 1rem;
    position: relative;
    z-index: 1;
}

.stat-icon.icon-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.stat-icon.icon-success {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
}

.stat-icon.icon-warning {
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    color: white;
}

.stat-icon.icon-info {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    color: white;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0.5rem 0;
    position: relative;
    z-index: 1;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    position: relative;
    z-index: 1;
}

/* ==================
   Buttons
   ================== */
.btn {
    padding: 0.625rem 1.25rem;
    border-radius: var(--border-radius-sm);
    font-weight: 600;
    font-size: 0.9375rem;
    transition: all var(--transition-base);
    border: none;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn:active {
    transform: translateY(0);
}

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

.btn-success {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
}

.btn-warning {
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
    color: white;
}

.btn-outline-primary {
    background: transparent;
    border: 2px solid var(--brand-primary);
    color: var(--brand-primary);
}

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

.btn-sm {
    padding: 0.375rem 0.75rem;
    font-size: 0.875rem;
}

.btn-lg {
    padding: 0.875rem 1.75rem;
    font-size: 1.0625rem;
}

/* ==================
   Forms
   ================== */
.form-control {
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 0.9375rem;
    transition: all var(--transition-base);
    width: 100%;
}

.form-control:focus {
    outline: none;
    border-color: var(--brand-primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
    transform: translateY(-2px);
}

.form-label {
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
    display: block;
}

.form-group {
    margin-bottom: 1.5rem;
}

/* ==================
   Tables
   ================== */
.table-responsive {
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.table {
    width: 100%;
    margin-bottom: 0;
    background: var(--bg-secondary);
}

.table thead th {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-weight: 600;
    padding: 1rem;
    border: none;
    text-transform: uppercase;
    font-size: 0.8125rem;
    letter-spacing: 0.5px;
}

.table tbody td {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
    vertical-align: middle;
}

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

.table tbody tr:hover {
    background: var(--bg-tertiary);
    transform: scale(1.01);
}

/* ==================
   Badges
   ================== */
.badge {
    padding: 0.375rem 0.75rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 600;
    display: inline-block;
}

.badge.bg-primary {
    background: var(--brand-primary);
    color: white;
}

.badge.bg-success {
    background: var(--accent-success);
    color: white;
}

.badge.bg-warning {
    background: var(--accent-warning);
    color: white;
}

.badge.bg-danger {
    background: var(--accent-danger);
    color: white;
}

.badge.bg-info {
    background: var(--accent-info);
    color: white;
}

/* ==================
   Animations
   ================== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

.fade-in {
    animation: fadeIn 0.6s ease forwards;
}

.slide-in-left {
    animation: slideInLeft 0.6s ease forwards;
}

.stagger-1 {
    animation-delay: 0.1s;
    opacity: 0;
}

.stagger-2 {
    animation-delay: 0.2s;
    opacity: 0;
}

.stagger-3 {
    animation-delay: 0.3s;
    opacity: 0;
}

.stagger-4 {
    animation-delay: 0.4s;
    opacity: 0;
}

.stagger-5 {
    animation-delay: 0.5s;
    opacity: 0;
}

.stagger-6 {
    animation-delay: 0.6s;
    opacity: 0;
}

/* ==================
   Loading States
   ================== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.loading-overlay.active {
    opacity: 1;
    visibility: visible;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

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

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

    .content {
        margin-left: 0;
    }

    .main-content {
        padding: 1rem;
    }

    .stat-card {
        margin-bottom: 1rem;
    }
}

/* ==================
   Utility Classes
   ================== */
.text-gradient {
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
}

.shadow-sm {
    box-shadow: var(--shadow-sm);
}

.shadow-md {
    box-shadow: var(--shadow-md);
}

.shadow-lg {
    box-shadow: var(--shadow-lg);
}

.shadow-xl {
    box-shadow: var(--shadow-xl);
}

.mt-1 {
    margin-top: 0.5rem;
}

.mt-2 {
    margin-top: 1rem;
}

.mt-3 {
    margin-top: 1.5rem;
}

.mt-4 {
    margin-top: 2rem;
}

.mb-1 {
    margin-bottom: 0.5rem;
}

.mb-2 {
    margin-bottom: 1rem;
}

.mb-3 {
    margin-bottom: 1.5rem;
}

.mb-4 {
    margin-bottom: 2rem;
}

.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
}

::-webkit-scrollbar-thumb {
    background: var(--brand-primary);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--brand-secondary);
}