/**
 * REDESIGNED STYLESHEET
 * Platform Pembelajaran Interaktif - Modern & Responsive Design
 */

/* ==============================================
   1. ROOT VARIABLES - Skema Warna Baru
   ============================================== */
:root {
    /* Primary Colors - Gradasi Biru-Ungu Modern */
    --primary-start: #6366f1;
    --primary-end: #8b5cf6;
    --primary-color: #7c3aed;
    --primary-light: #a78bfa;
    --primary-dark: #5b21b6;
    
    /* Secondary Colors */
    --secondary-color: #64748b;
    --accent-color: #f59e0b;
    --accent-light: #fbbf24;
    
    /* Status Colors */
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #06b6d4;
    
    /* Neutral Colors */
    --light-bg: #f8fafc;
    --white: #ffffff;
    --dark-color: #1e293b;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-600: #475569;
    --gray-800: #1e293b;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Oxygen', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 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 rgba(0, 0, 0, 0.05);
    --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);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==============================================
   2. GENERAL STYLES
   ============================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.main-content {
    min-height: calc(100vh - 200px);
    padding-top: var(--spacing-2xl);
    padding-bottom: var(--spacing-2xl);
}

/* ==============================================
   3. NAVBAR STYLES - Redesigned
   ============================================== */
.navbar {
    background: rgba(255, 255, 255, 0.95) !important;
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-200);
    transition: all var(--transition-base);
    padding: var(--spacing-md) 0;
}

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

.navbar-brand {
    font-size: var(--font-size-xl);
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: transform var(--transition-base);
}

.navbar-brand:hover {
    transform: scale(1.05);
}

.navbar-brand i {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-link {
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-lg) !important;
    transition: all var(--transition-base);
    position: relative;
    color: var(--gray-600) !important;
    border-radius: var(--radius-md);
    margin: 0 var(--spacing-xs);
}

.nav-link:hover {
    color: var(--primary-color) !important;
    background-color: var(--gray-100);
}

.nav-link.active {
    color: var(--primary-color) !important;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(139, 92, 246, 0.1));
}

.nav-link.active::after {
    display: none;
}

/* Search in navbar */
.navbar .input-group {
    max-width: 300px;
    transition: all var(--transition-base);
}

.navbar .input-group:focus-within {
    max-width: 350px;
}

.navbar .form-control {
    border-radius: var(--radius-full);
    border: 2px solid var(--gray-200);
    padding: var(--spacing-sm) var(--spacing-lg);
    transition: all var(--transition-base);
}

.navbar .form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(124, 58, 237, 0.1);
}

.navbar .btn-primary {
    border-radius: var(--radius-full);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    border: none;
}

@media (max-width: 991px) {
    .navbar .input-group {
        max-width: 100%;
        margin-top: var(--spacing-md);
    }
    
    .nav-link {
        margin: var(--spacing-xs) 0;
    }
}

/* ==============================================
   4. HERO SECTION - Redesigned
   ============================================== */
.hero-section {
    background: linear-gradient(135deg, var(--primary-start) 0%, var(--primary-end) 100%);
    color: white;
    padding: var(--spacing-3xl) 0;
    margin-bottom: var(--spacing-2xl);
    border-radius: 0 0 var(--radius-2xl) var(--radius-2xl);
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    opacity: 0.3;
}

.hero-section .container {
    position: relative;
    z-index: 1;
}

.hero-section h1 {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    margin-bottom: var(--spacing-lg);
    line-height: 1.2;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.hero-section p {
    font-size: var(--font-size-lg);
    opacity: 0.95;
    max-width: 600px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.7;
}

.hero-section .btn {
    padding: var(--spacing-md) var(--spacing-2xl);
    font-size: var(--font-size-lg);
    font-weight: 600;
    border-radius: var(--radius-full);
    margin: var(--spacing-sm);
    box-shadow: var(--shadow-lg);
}

.hero-section .btn-light {
    background: white;
    color: var(--primary-color);
    border: 2px solid white;
}

.hero-section .btn-light:hover {
    background: transparent;
    color: white;
    border-color: white;
}

.hero-section .btn-outline-light {
    border: 2px solid white;
    color: white;
}

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

@media (max-width: 768px) {
    .hero-section {
        padding: var(--spacing-2xl) 0;
    }
    
    .hero-section h1 {
        font-size: var(--font-size-3xl);
    }
    
    .hero-section p {
        font-size: var(--font-size-base);
    }
    
    .hero-section .btn {
        font-size: var(--font-size-base);
        padding: var(--spacing-sm) var(--spacing-xl);
        display: block;
        width: 100%;
        margin: var(--spacing-sm) 0;
    }
}

/* ==============================================
   5. CARDS - Redesigned
   ============================================== */
.card {
    border: none;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    height: 100%;
    background: white;
    overflow: hidden;
    position: relative;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-start), var(--primary-end));
    transform: scaleX(0);
    transition: transform var(--transition-base);
}

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

.card:hover::before {
    transform: scaleX(1);
}

.card-img-top {
    border-radius: 0;
    height: 200px;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.card:hover .card-img-top {
    transform: scale(1.05);
}

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

.card-title {
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-lg);
    line-height: 1.4;
}

.card-text {
    color: var(--gray-600);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    margin-bottom: var(--spacing-lg);
}

/* Card badges */
.card-badge {
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: 700;
    z-index: 10;
    backdrop-filter: blur(10px);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-materi {
    background: rgba(6, 182, 212, 0.9);
    color: white;
}

.badge-latihan {
    background: rgba(245, 158, 11, 0.9);
    color: white;
}

/* ==============================================
   6. CONTENT GRID - Responsive
   ============================================== */
.content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

@media (max-width: 1200px) {
    .content-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    }
}

@media (max-width: 768px) {
    .content-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
}

/* ==============================================
   7. FILTER SECTION - Redesigned
   ============================================== */
.filter-section {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-2xl);
    border: 1px solid var(--gray-200);
}

.filter-section .form-select,
.filter-section .form-control {
    border-radius: var(--radius-lg);
    border: 2px solid var(--gray-200);
    padding: var(--spacing-md) var(--spacing-lg);
    transition: all var(--transition-base);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.filter-section .form-select:focus,
.filter-section .form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(124, 58, 237, 0.1);
    outline: none;
}

.filter-section .form-label {
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: var(--spacing-sm);
    font-size: var(--font-size-sm);
}

/* ==============================================
   8. STATS SECTION - Redesigned
   ============================================== */
.stats-card {
    background: linear-gradient(135deg, white, var(--gray-100));
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: all var(--transition-base);
    border: 1px solid var(--gray-200);
    position: relative;
    overflow: hidden;
}

.stats-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 100%;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.05), rgba(139, 92, 246, 0.05));
    transform: translateY(100%);
    transition: transform var(--transition-base);
}

.stats-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-light);
}

.stats-card:hover::before {
    transform: translateY(0);
}

.stats-card .stats-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    position: relative;
    z-index: 1;
}

.stats-card .stats-number {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-xs);
    position: relative;
    z-index: 1;
}

.stats-card .stats-label {
    color: var(--gray-600);
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    position: relative;
    z-index: 1;
}

/* Stats always visible */
.stats-visible,
.stats-row-visible .stats-card {
    opacity: 1 !important;
    visibility: visible !important;
}

/* ==============================================
   9. CATEGORY BADGES - Redesigned
   ============================================== */
.category-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin: var(--spacing-xs);
    transition: all var(--transition-base);
    text-decoration: none;
    border: 2px solid transparent;
}

.category-badge:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    text-decoration: none;
}

/* Jenjang colors - More vibrant */
.badge-sd { 
    background: linear-gradient(135deg, #fbbf24, #f59e0b); 
    color: white;
    border-color: #f59e0b;
}

.badge-sd:hover {
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

.badge-smp { 
    background: linear-gradient(135deg, #06b6d4, #0891b2); 
    color: white;
    border-color: #0891b2;
}

.badge-smp:hover {
    box-shadow: 0 4px 12px rgba(6, 182, 212, 0.4);
}

.badge-sma { 
    background: linear-gradient(135deg, #8b5cf6, #7c3aed); 
    color: white;
    border-color: #7c3aed;
}

.badge-sma:hover {
    box-shadow: 0 4px 12px rgba(139, 92, 246, 0.4);
}

.badge-umum { 
    background: linear-gradient(135deg, #ec4899, #db2777); 
    color: white;
    border-color: #db2777;
}

.badge-umum:hover {
    box-shadow: 0 4px 12px rgba(236, 72, 153, 0.4);
}

/* ==============================================
   10. BUTTONS - Redesigned
   ============================================== */
.btn {
    border-radius: var(--radius-lg);
    padding: var(--spacing-md) var(--spacing-xl);
    font-weight: 600;
    transition: all var(--transition-base);
    border: 2px solid transparent;
    font-size: var(--font-size-sm);
    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-primary {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    border-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(124, 58, 237, 0.3);
    background: linear-gradient(135deg, var(--primary-end), var(--primary-start));
}

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

.btn-outline-primary:hover {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    border-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.btn-warning {
    background: linear-gradient(135deg, var(--warning-color), var(--accent-light));
    border-color: var(--warning-color);
    color: white;
}

.btn-warning:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(245, 158, 11, 0.3);
}

.btn-floating {
    position: fixed;
    bottom: var(--spacing-2xl);
    right: var(--spacing-2xl);
    width: 56px;
    height: 56px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-xl);
    z-index: 1000;
    transition: all var(--transition-base);
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    border: none;
    color: white;
}

.btn-floating:hover {
    transform: scale(1.1) rotate(10deg);
    box-shadow: var(--shadow-2xl);
}

/* ==============================================
   11. SEARCH RESULTS - Redesigned
   ============================================== */
.search-result {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-lg);
    transition: all var(--transition-base);
    border: 1px solid var(--gray-200);
    border-left: 4px solid var(--primary-color);
}

.search-result:hover {
    box-shadow: var(--shadow-lg);
    transform: translateX(4px);
    border-left-width: 6px;
}

.search-result h5 {
    margin-bottom: var(--spacing-sm);
    color: var(--dark-color);
    font-weight: 700;
}

.search-result .meta {
    color: var(--gray-600);
    font-size: var(--font-size-xs);
    margin-bottom: var(--spacing-sm);
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.search-highlight {
    background: linear-gradient(135deg, rgba(245, 158, 11, 0.2), rgba(251, 191, 36, 0.2));
    padding: 2px var(--spacing-xs);
    border-radius: var(--radius-sm);
    font-weight: 600;
}

/* ==============================================
   12. FOOTER - Redesigned & Balanced
   ============================================== */
.footer {
    margin-top: auto;
    background: linear-gradient(135deg, #1e293b 0%, #334155 100%);
    color: white;
    padding: var(--spacing-2xl) 0 var(--spacing-md);
    position: relative;
    overflow: hidden;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
}

.footer h5 {
    font-size: var(--font-size-lg);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: white;
}

.footer p {
    font-size: var(--font-size-sm);
    line-height: 1.6;
    margin-bottom: var(--spacing-sm);
}

.footer ul {
    padding-left: 0;
}

.footer ul li {
    margin-bottom: var(--spacing-sm);
}

.footer a {
    color: var(--gray-300);
    transition: all var(--transition-base);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
}

.footer a:hover {
    color: var(--primary-light) !important;
    transform: translateX(4px);
}

.footer a i {
    font-size: 1rem;
}

.footer .text-muted {
    color: var(--gray-400) !important;
}

.footer .border-secondary {
    border-color: rgba(255, 255, 255, 0.1) !important;
    margin: var(--spacing-xl) 0;
}

.footer .small {
    font-size: var(--font-size-xs);
}

/* Social Links - More Compact */
.social-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-md);
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: var(--radius-md);
    background: rgba(255, 255, 255, 0.08);
    transition: all var(--transition-base);
    border: 1px solid rgba(255, 255, 255, 0.1);
    font-size: var(--font-size-sm);
}

.social-links a:hover {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(124, 58, 237, 0.4);
    border-color: var(--primary-color);
}

/* Footer Copyright Section */
.footer .row:last-child {
    margin-top: var(--spacing-lg);
}

.footer .row:last-child p {
    margin-bottom: 0;
    opacity: 0.8;
}

/* Responsive Footer */
@media (max-width: 768px) {
    .footer {
        padding: var(--spacing-xl) 0 var(--spacing-md);
    }
    
    .footer .col-md-4 {
        margin-bottom: var(--spacing-lg);
    }
    
    .footer h5 {
        font-size: var(--font-size-base);
    }
    
    .footer p,
    .footer a {
        font-size: var(--font-size-xs);
    }
    
    .social-links {
        justify-content: center;
    }
    
    .footer .text-md-start,
    .footer .text-md-end {
        text-align: center !important;
    }
}

/* ==============================================
   13. PAGINATION - Redesigned
   ============================================== */
.pagination {
    margin-top: var(--spacing-2xl);
    gap: var(--spacing-xs);
}

.page-link {
    color: var(--primary-color);
    border-radius: var(--radius-md);
    border: 2px solid var(--gray-200);
    margin: 0 var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    transition: all var(--transition-base);
    font-weight: 600;
}

.page-link:hover {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    color: white;
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.page-item.active .page-link {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

/* ==============================================
   14. VIEWER STYLES - Redesigned
   ============================================== */
.viewer-container {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
    border: 1px solid var(--gray-200);
}

.viewer-header {
    border-bottom: 2px solid var(--gray-200);
    padding-bottom: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.viewer-content {
    min-height: 500px;
}

.slide-frame {
    width: 100%;
    min-height: 600px;
    border: none;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

/* ==============================================
   15. ALERTS - Redesigned
   ============================================== */
.alert {
    border-radius: var(--radius-lg);
    border: none;
    box-shadow: var(--shadow-md);
    padding: var(--spacing-lg);
    border-left: 4px solid;
}

.alert-success {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(16, 185, 129, 0.05));
    border-left-color: var(--success-color);
    color: var(--success-color);
}

.alert-warning {
    background: linear-gradient(135deg, rgba(245, 158, 11, 0.1), rgba(245, 158, 11, 0.05));
    border-left-color: var(--warning-color);
    color: #92400e;
}

.alert-danger {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.1), rgba(239, 68, 68, 0.05));
    border-left-color: var(--danger-color);
    color: #991b1b;
}

.alert-info {
    background: linear-gradient(135deg, rgba(6, 182, 212, 0.1), rgba(6, 182, 212, 0.05));
    border-left-color: var(--info-color);
    color: #155e75;
}

/* ==============================================
   16. ANIMATIONS - Enhanced
   ============================================== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideInUp {
    from {
        transform: translateY(100px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.slide-in-up {
    animation: slideInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideInLeft {
    from {
        transform: translateX(-50px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.slide-in-left {
    animation: slideInLeft 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

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

@keyframes shimmer {
    0% {
        background-position: -1000px 0;
    }
    100% {
        background-position: 1000px 0;
    }
}

.shimmer {
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.5), transparent);
    background-size: 1000px 100%;
    animation: shimmer 2s infinite;
}

/* ==============================================
   17. UTILITIES - Extended
   ============================================== */
.text-truncate-2 {
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.text-truncate-3 {
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Meta info */
.meta-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    font-size: var(--font-size-sm);
    color: var(--gray-600);
}

.meta-info i {
    margin-right: var(--spacing-xs);
    color: var(--primary-color);
}

.meta-info > div {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

/* Views counter */
.views-count {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--gray-600);
    font-size: var(--font-size-sm);
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--gray-100);
    border-radius: var(--radius-full);
}

/* Loading spinner */
.loading-spinner {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 300px;
}

.spinner-border {
    width: 3rem;
    height: 3rem;
    border-width: 0.3rem;
    border-color: var(--primary-color);
    border-right-color: transparent;
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-lg);
}

.empty-state i {
    font-size: 5rem;
    color: var(--gray-400);
    margin-bottom: var(--spacing-xl);
    opacity: 0.5;
}

.empty-state h4 {
    color: var(--gray-600);
    margin-bottom: var(--spacing-md);
    font-weight: 700;
}

.empty-state p {
    color: var(--gray-600);
    max-width: 500px;
    margin: 0 auto;
}

/* ==============================================
   18. RESPONSIVE DESIGN - Mobile First
   ============================================== */
@media (max-width: 576px) {
    :root {
        --font-size-4xl: 1.875rem;
        --font-size-3xl: 1.5rem;
        --font-size-2xl: 1.25rem;
        --spacing-3xl: 2.5rem;
        --spacing-2xl: 2rem;
    }
    
    .container {
        padding-left: var(--spacing-md);
        padding-right: var(--spacing-md);
    }
    
    .btn {
        font-size: var(--font-size-sm);
        padding: var(--spacing-sm) var(--spacing-lg);
    }
    
    .card-body {
        padding: var(--spacing-lg);
    }
    
    .filter-section {
        padding: var(--spacing-lg);
    }
    
    .btn-floating {
        bottom: var(--spacing-lg);
        right: var(--spacing-lg);
        width: 48px;
        height: 48px;
    }
    
    .stats-card {
        padding: var(--spacing-lg);
    }
    
    .stats-card .stats-icon {
        font-size: 2.5rem;
    }
    
    .stats-card .stats-number {
        font-size: var(--font-size-3xl);
    }
}

@media (max-width: 768px) {
    .hero-section {
        text-align: center;
    }
    
    .hero-section p {
        margin-left: auto;
        margin-right: auto;
    }
    
    .viewer-container {
        padding: var(--spacing-lg);
    }
    
    .slide-frame {
        min-height: 400px;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .content-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1025px) {
    .content-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ==============================================
   19. DARK MODE SUPPORT (Optional)
   ============================================== */
@media (prefers-color-scheme: dark) {
    :root {
        --light-bg: #0f172a;
        --white: #1e293b;
        --dark-color: #f1f5f9;
        --gray-100: #1e293b;
        --gray-200: #334155;
        --gray-300: #475569;
        --gray-600: #cbd5e1;
        --gray-800: #f1f5f9;
    }
}

/* ==============================================
   20. ACCESSIBILITY IMPROVEMENTS
   ============================================== */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

*:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ==============================================
   21. PRINT STYLES
   ============================================== */
@media print {
    .navbar,
    .footer,
    .btn-floating,
    .filter-section,
    .btn,
    .social-links {
        display: none !important;
    }
    
    .main-content {
        padding: 0;
    }
    
    .card,
    .viewer-container {
        box-shadow: none !important;
        border: 1px solid #000;
    }
    
    body {
        background: white;
    }
}

/* ==============================================
   22. CUSTOM SCROLLBAR
   ============================================== */
::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

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

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    border-radius: var(--radius-full);
    border: 2px solid var(--gray-100);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, var(--primary-end), var(--primary-start));
}

/* ==============================================
   23. READING PROGRESS BAR
   ============================================== */
.reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-start), var(--primary-end));
    width: 0%;
    z-index: 9999;
    transition: width 0.1s ease;
    box-shadow: 0 0 10px rgba(124, 58, 237, 0.5);
}

/* ==============================================
   24. BACKDROP BLUR EFFECTS
   ============================================== */
.backdrop-blur {
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.glass-effect {
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* ==============================================
   25. SKELETON LOADING
   ============================================== */
.skeleton {
    background: linear-gradient(90deg, var(--gray-200) 25%, var(--gray-300) 50%, var(--gray-200) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

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

.skeleton-text {
    height: 1rem;
    margin-bottom: var(--spacing-sm);
}

.skeleton-title {
    height: 1.5rem;
    width: 60%;
    margin-bottom: var(--spacing-md);
}

.skeleton-image {
    height: 200px;
    width: 100%;
}

/* ==============================================
   26. HOVER EFFECTS FOR INTERACTIVE ELEMENTS
   ============================================== */
.hover-lift {
    transition: transform var(--transition-base);
}

.hover-lift:hover {
    transform: translateY(-4px);
}

.hover-scale {
    transition: transform var(--transition-base);
}

.hover-scale:hover {
    transform: scale(1.05);
}

.hover-glow {
    transition: box-shadow var(--transition-base);
}

.hover-glow:hover {
    box-shadow: 0 0 20px rgba(124, 58, 237, 0.4);
}

/* ==============================================
   27. BADGE STYLES
   ============================================== */
.badge {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: 700;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.badge-primary {
    background: linear-gradient(135deg, var(--primary-start), var(--primary-end));
    color: white;
}

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

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

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

/* ==============================================
   28. TOOLTIP CUSTOM STYLES
   ============================================== */
.tooltip {
    font-size: var(--font-size-sm);
}

.tooltip-inner {
    background: var(--dark-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm) var(--spacing-md);
    box-shadow: var(--shadow-lg);
}

/* ==============================================
   29. FORM IMPROVEMENTS
   ============================================== */
.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(124, 58, 237, 0.1);
}

.form-label {
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: var(--spacing-sm);
}

.input-group-text {
    background: var(--gray-100);
    border: 2px solid var(--gray-200);
    color: var(--gray-600);
}

/* ==============================================
   30. SECTION DIVIDERS & UTILITIES
   ============================================== */
.section-divider {
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
    margin: var(--spacing-2xl) 0;
}

.section-title {
    position: relative;
    padding-bottom: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-start), var(--primary-end));
    border-radius: var(--radius-full);
}

/* Compact spacing for footer */
.g-4 {
    --bs-gutter-y: 1.5rem;
    --bs-gutter-x: 1.5rem;
}

/* Better link hover in footer */
.footer a:not(.social-links a) {
    position: relative;
}

.footer a:not(.social-links a)::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--primary-light);
    transition: width var(--transition-base);
}

.footer a:not(.social-links a):hover::after {
    width: 100%;
}

/* Footer mobile improvements */
@media (max-width: 576px) {
    .footer .col-lg-4,
    .footer .col-lg-3,
    .footer .col-lg-5 {
        text-align: center;
    }
    
    .footer ul {
        display: inline-block;
        text-align: left;
    }
    
    .footer .social-links {
        justify-content: center;
    }
}