/* 
 * Modern UI Enhancements inspired by MkSaaS
 * Adding gradient effects, animations, and modern styling
 */

/* Dark Mode Variables */
:root {
    --bg-light: #ffffff;
    --bg-dark: #0f0f0f;
    --text-light: #333333;
    --text-dark: #e0e0e0;
    --card-bg-light: rgba(255, 255, 255, 0.95);
    --card-bg-dark: rgba(20, 20, 20, 0.95);
    --border-light: rgba(0, 0, 0, 0.1);
    --border-dark: rgba(255, 255, 255, 0.1);
    --shadow-light: rgba(0, 0, 0, 0.1);
    --shadow-dark: rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
    --bg-primary: var(--bg-light);
    --text-primary: var(--text-light);
    --card-bg: var(--card-bg-light);
    --border-color: var(--border-light);
    --shadow-color: var(--shadow-light);
}

[data-theme="dark"] {
    --bg-primary: var(--bg-dark);
    --text-primary: var(--text-dark);
    --card-bg: var(--card-bg-dark);
    --border-color: var(--border-dark);
    --shadow-color: var(--shadow-dark);
}

/* Apply theme colors */
body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Dark mode toggle button */
.theme-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    box-shadow: 0 4px 12px var(--shadow-color);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 1000;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 20px var(--shadow-color);
}

.theme-toggle svg {
    width: 24px;
    height: 24px;
    fill: var(--text-primary);
    transition: transform 0.3s ease;
}

.theme-toggle:hover svg {
    transform: rotate(180deg);
}

/* Reading Progress Bar */
.reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: rgba(0, 0, 0, 0.1);
    z-index: 9999;
    transition: opacity 0.3s ease;
}

[data-theme="dark"] .reading-progress {
    background: rgba(255, 255, 255, 0.1);
}

.reading-progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #3B82F6 0%, #8B5CF6 50%, #06B6D4 100%);
    width: 0%;
    transition: width 0.1s ease;
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.5);
}

/* Article Table of Contents */
.article-toc {
    position: sticky;
    top: 100px;
    padding: 1.5rem;
    background: var(--card-bg);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    max-height: calc(100vh - 120px);
    overflow-y: auto;
}

.article-toc h3 {
    margin: 0 0 1rem 0;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-primary);
    opacity: 0.8;
}

.article-toc ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.article-toc li {
    margin-bottom: 0.5rem;
}

.article-toc a {
    color: var(--text-primary);
    text-decoration: none;
    opacity: 0.7;
    transition: all 0.3s ease;
    display: block;
    padding: 0.25rem 0.5rem;
    border-left: 2px solid transparent;
}

.article-toc a:hover {
    opacity: 1;
    padding-left: 1rem;
    border-left-color: #3B82F6;
}

.article-toc a.active {
    opacity: 1;
    color: #3B82F6;
    border-left-color: #3B82F6;
    background: linear-gradient(90deg, rgba(59, 130, 246, 0.1) 0%, transparent 100%);
}

/* Scrollbar styling for TOC */
.article-toc::-webkit-scrollbar {
    width: 6px;
}

.article-toc::-webkit-scrollbar-track {
    background: transparent;
}

.article-toc::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.article-toc::-webkit-scrollbar-thumb:hover {
    background: #3B82F6;
}

/* Learning Tracker Styles */
.learning-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: var(--card-bg);
    border-radius: 12px;
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

.progress-actions {
    display: flex;
    gap: 1rem;
}

.btn-progress {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-progress:hover {
    background: rgba(59, 130, 246, 0.1);
    border-color: #3B82F6;
    transform: translateY(-2px);
}

.btn-progress.active {
    background: #3B82F6;
    color: white;
    border-color: #3B82F6;
}

.reading-stats {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-primary);
    opacity: 0.8;
}

/* Progress Badges */
.progress-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    font-size: 12px;
    margin-left: 0.5rem;
}

.progress-badge.completed {
    background: #10B981;
    color: white;
}

.progress-badge.in-progress {
    background: #F59E0B;
    color: white;
}

/* Notes Modal */
.notes-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 10000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.notes-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
}

.notes-content {
    position: relative;
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    width: 90%;
    max-width: 500px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.notes-textarea {
    width: 100%;
    min-height: 200px;
    padding: 1rem;
    background: var(--bg-primary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    resize: vertical;
    font-family: inherit;
    margin: 1rem 0;
}

.notes-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
}

.btn-cancel, .btn-save {
    padding: 0.5rem 1.5rem;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-cancel {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}

.btn-save {
    background: #3B82F6;
    color: white;
}

/* Achievement Notification */
.achievement-notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1rem 1.5rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    display: flex;
    align-items: center;
    gap: 1rem;
    transform: translateX(400px);
    transition: transform 0.3s ease;
    z-index: 10001;
}

.achievement-notification.show {
    transform: translateX(0);
}

.achievement-icon {
    font-size: 2rem;
}

.achievement-content h4 {
    margin: 0 0 0.25rem 0;
    color: var(--text-primary);
}

.achievement-content p {
    margin: 0;
    color: #3B82F6;
    font-weight: 600;
}

.achievement-content small {
    color: var(--text-primary);
    opacity: 0.8;
}


/* Gradient Text Effects */
.text-gradient {
    background: linear-gradient(135deg, #3B82F6 0%, #8B5CF6 50%, #06B6D4 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.text-gradient-primary {
    background: linear-gradient(135deg, #3B82F6 0%, #1D4ED8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Modern Card Effects */
.card-modern {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    transition: all 0.3s ease;
}

.card-modern:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    border-color: rgba(59, 130, 246, 0.3);
}

/* Animated Gradient Borders */
.border-gradient {
    position: relative;
    background: var(--light-color);
    border-radius: 16px;
    padding: 2px;
    display: inline-block;
}

.border-gradient .btn {
    display: block;
    width: 100%;
    margin: 0;
    border-radius: 14px;
}

.border-gradient::before {
    content: '';
    position: absolute;
    inset: 0;
    padding: 2px;
    background: linear-gradient(135deg, #3B82F6, #8B5CF6, #06B6D4);
    border-radius: inherit;
    mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    mask-composite: exclude;
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
}

/* Floating Animation */
@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.float-animation {
    animation: float 3s ease-in-out infinite;
}

.float-animation:nth-child(2) {
    animation-delay: 0.5s;
}

.float-animation:nth-child(3) {
    animation-delay: 1s;
}

/* Modern Button Styles */
.btn-modern {
    position: relative;
    background: linear-gradient(135deg, #3B82F6 0%, #1D4ED8 100%);
    border: none;
    border-radius: 12px;
    color: white;
    padding: 12px 24px;
    font-weight: 600;
    transition: all 0.3s ease;
    overflow: hidden;
}

.btn-modern::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn-modern:hover::before {
    left: 100%;
}

.btn-modern:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(59, 130, 246, 0.3);
}

/* Glassmorphism Effects */
.glass {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 16px;
}

.glass-dark {
    background: rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
}

/* Animated Background Patterns */
.animated-bg {
    background: linear-gradient(-45deg, #3B82F6, #8B5CF6, #06B6D4, #10B981);
    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%; }
}

/* Pulse Effect */
.pulse-ring {
    position: relative;
}

.pulse-ring::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 100%;
    height: 100%;
    background: rgba(59, 130, 246, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%) scale(1);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(1.5);
        opacity: 0;
    }
}

/* Modern Input Styles */
.input-modern {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: 16px;
    color: var(--text-color);
    transition: all 0.3s ease;
}

.input-modern:focus {
    outline: none;
    border-color: #3B82F6;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
    background: rgba(255, 255, 255, 0.1);
}

/* Enhanced Hero Section */
.hero-modern {
    position: relative;
    overflow: hidden;
    background: radial-gradient(ellipse 80% 50% at 50% -20%, rgba(59, 130, 246, 0.15), transparent);
    color: var(--text-color);
}

.hero-modern .hero-title {
    color: var(--dark-color);
}

.hero-modern .hero-subtitle {
    color: var(--text-color);
    opacity: 0.8;
}

.hero-modern .stat-number {
    color: var(--dark-color);
}

.hero-modern .stat-label {
    color: var(--text-color);
    opacity: 0.7;
}

/* Button overrides for modern hero */
.hero-modern .btn-secondary.glass {
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
    border: 1px solid rgba(59, 130, 246, 0.3);
}

.hero-modern .btn-secondary.glass:hover {
    background: var(--primary-color);
    color: white;
}

.hero-modern::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 80%, rgba(139, 92, 246, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(6, 182, 212, 0.15) 0%, transparent 50%);
    pointer-events: none;
}

/* Modern Card Grid */
.grid-modern {
    display: grid;
    gap: 24px;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-modern .card,
.grid-modern .category-card {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.8) 0%, rgba(255, 255, 255, 0.9) 100%);
    border: 1px solid rgba(59, 130, 246, 0.1);
    border-radius: 20px;
    padding: 32px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.grid-modern .card::before,
.grid-modern .category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, #3B82F6, #8B5CF6, #06B6D4);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.grid-modern .card:hover::before,
.grid-modern .category-card:hover::before {
    transform: scaleX(1);
}

.grid-modern .card:hover,
.grid-modern .category-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.15);
}

/* Category card specific styles */
.category-card h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.category-card p {
    color: var(--text-color);
    opacity: 0.8;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.category-icon {
    font-size: 2rem;
    margin-bottom: 1rem;
    display: block;
}

.category-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

/* Scroll-triggered Animations */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.fade-in-up.animate {
    opacity: 1;
    transform: translateY(0);
}

/* Progress Indicators */
.progress-modern {
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
}

.progress-modern .progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #3B82F6, #8B5CF6);
    border-radius: 4px;
    transition: width 0.3s ease;
}

/* Interactive Elements */
.interactive-glow {
    position: relative;
    transition: all 0.3s ease;
}

.interactive-glow:hover {
    box-shadow: 0 0 30px rgba(59, 130, 246, 0.3);
}

/* Particle Effect Background */
.particles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    pointer-events: none;
    z-index: 1;
}

.particle {
    position: absolute;
    width: 4px;
    height: 4px;
    background: rgba(59, 130, 246, 0.5);
    border-radius: 50%;
    animation: floatParticle 6s linear infinite;
    pointer-events: none;
}

@keyframes floatParticle {
    0% {
        transform: translateY(100vh) rotate(0deg);
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        transform: translateY(-100px) rotate(360deg);
        opacity: 0;
    }
}

/* Dark Mode Adaptations */
@media (prefers-color-scheme: dark) {
    .card-modern {
        background: rgba(0, 0, 0, 0.3);
        border-color: rgba(255, 255, 255, 0.1);
    }
    
    .glass {
        background: rgba(0, 0, 0, 0.2);
        border-color: rgba(255, 255, 255, 0.1);
    }
    
    .input-modern {
        background: rgba(0, 0, 0, 0.3);
        border-color: rgba(255, 255, 255, 0.1);
    }
}

/* Lazy Loading Styles */
.lazy-image {
    opacity: 0;
    transition: opacity 0.3s ease;
}

.lazy-image.loaded {
    opacity: 1;
}

img[data-src],
img[data-srcset] {
    filter: blur(5px);
    transition: filter 0.3s ease;
}

img.loaded {
    filter: blur(0);
}

/* Image loading placeholder */
.image-placeholder {
    background: linear-gradient(90deg, #f3f4f6 0%, #e5e7eb 50%, #f3f4f6 100%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}

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

/* Responsive Enhancements */
@media (max-width: 768px) {
    .grid-modern {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .hero-modern {
        padding: 60px 0;
    }
    
    .card-modern {
        padding: 24px;
    }
    
    .learning-controls {
        flex-direction: column;
        gap: 1rem;
    }
    
    .progress-actions {
        width: 100%;
        justify-content: space-between;
    }
    
    .article-toc {
        display: none;
    }
}