/* =============================================
   Basics of AI - PREMIUM LIGHT THEME EDITION
   Author: Rajesh Pandhare, Kanaka Software
   Ultra-Premium Design with Light/White Theme
   Beautiful gradient animations on clean white
   ============================================= */

/* Import Google Fonts for premium typography */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Playfair+Display:wght@700;900&display=swap');

/* CSS Variables - Premium Light Color Palette */
:root {
    /* Vibrant Primary Colors */
    --primary-color: #6366f1;
    --primary-light: #818cf8;
    --primary-dark: #4338ca;
    --primary-glow: #a5b4fc;
    
    /* Accent Colors - Rich and Bold */
    --accent-cyan: #06b6d4;
    --accent-pink: #ec4899;
    --accent-purple: #a855f7;
    --accent-orange: #f59e0b;
    --accent-green: #10b981;
    
    /* Neon Glow Colors */
    --neon-blue: #00d4ff;
    --neon-purple: #b74dff;
    --neon-pink: #ff006e;
    --neon-cyan: #00fff5;
    
    /* Light Theme Backgrounds */
    --bg-white: #ffffff;
    --bg-light: #f8fafc;
    --bg-lighter: #f1f5f9;
    --card-bg: #ffffff;
    --card-glass: rgba(255, 255, 255, 0.95);
    
    /* Dark Text Colors */
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #64748b;
    --text-light: #94a3b8;
    
    /* Layout */
    --sidebar-width: 280px;
    --border-radius: 24px;
    --border-radius-lg: 32px;
    --transition-fast: 0.2s;
    --transition-normal: 0.4s;
    --transition-slow: 0.8s;
    
    /* Shadows - Colorful and Soft */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.15);
    --shadow-neon: 0 0 40px rgba(99, 102, 241, 0.3), 0 0 80px rgba(99, 102, 241, 0.15);
    --shadow-neon-hover: 0 0 60px rgba(99, 102, 241, 0.4), 0 0 120px rgba(99, 102, 241, 0.2);
}

/* Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

/* BODY - Light Animated Gradient Background */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: linear-gradient(135deg, 
        #ffffff 0%, 
        #f0f9ff 15%,
        #fef3c7 30%,
        #fce7f3 45%,
        #f3e8ff 60%,
        #dbeafe 75%,
        #ffffff 100%);
    background-size: 400% 400%;
    animation: gradientMesh 20s ease infinite;
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    font-size: 18px;
    position: relative;
    overflow-x: hidden;
}

@keyframes gradientMesh {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

/* Soft Particle Overlay */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 20%),
        radial-gradient(circle at 90% 80%, rgba(236, 72, 153, 0.08) 0%, transparent 25%),
        radial-gradient(circle at 50% 50%, rgba(6, 182, 212, 0.06) 0%, transparent 30%),
        radial-gradient(circle at 30% 70%, rgba(168, 85, 247, 0.06) 0%, transparent 20%);
    animation: particleFloat 25s ease-in-out infinite;
    pointer-events: none;
    z-index: 1;
}

@keyframes particleFloat {
    0%, 100% { transform: translate(0, 0) scale(1); opacity: 1; }
    50% { transform: translate(20px, -20px) scale(1.05); opacity: 0.9; }
}

/* Subtle Floating Orbs */
body::after {
    content: '';
    position: fixed;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.04) 0%, transparent 70%);
    animation: orbRotate 40s linear infinite;
    pointer-events: none;
    z-index: 0;
}

@keyframes orbRotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* App Container */
.app-container {
    display: flex;
    min-height: 100vh;
    position: relative;
    z-index: 2;
}

/* =============================================
   SIDEBAR - Premium Light Glass Design
   ============================================= */

.sidebar {
    width: var(--sidebar-width);
    background: linear-gradient(180deg, 
        rgba(255, 255, 255, 0.98) 0%, 
        rgba(248, 250, 252, 0.98) 100%);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-right: 2px solid rgba(99, 102, 241, 0.15);
    color: var(--text-primary);
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg), 4px 0 24px rgba(99, 102, 241, 0.1);
    z-index: 100;
}

.sidebar::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="30" height="30" patternUnits="userSpaceOnUse"><circle cx="15" cy="15" r="1" fill="rgba(99,102,241,0.08)"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
    pointer-events: none;
}

.nav-header {
    padding: 40px 28px;
    border-bottom: 2px solid rgba(99, 102, 241, 0.12);
    position: relative;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.05) 0%, rgba(236, 72, 153, 0.05) 100%);
}

.nav-header h2 {
    font-family: 'Playfair Display', serif;
    font-size: 2.2rem;
    font-weight: 900;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, #6366f1 0%, #ec4899 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: titlePulse 3s ease-in-out infinite;
    filter: drop-shadow(0 2px 8px rgba(99, 102, 241, 0.2));
}

@keyframes titlePulse {
    0%, 100% { transform: scale(1); filter: brightness(1); }
    50% { transform: scale(1.02); filter: brightness(1.1); }
}

.nav-menu {
    list-style: none;
    padding: 24px 20px;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 18px 22px;
    margin-bottom: 12px;
    border-radius: 16px;
    cursor: pointer;
    transition: all var(--transition-normal) cubic-bezier(0.68, -0.55, 0.265, 1.55);
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-secondary);
    position: relative;
    overflow: hidden;
    border: 2px solid transparent;
}

.nav-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 5px;
    height: 100%;
    background: linear-gradient(180deg, #6366f1 0%, #ec4899 100%);
    transform: scaleY(0);
    transition: transform var(--transition-normal);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.6);
}

.nav-item::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, rgba(99, 102, 241, 0.08) 0%, transparent 100%);
    transform: translateX(-100%);
    transition: transform var(--transition-normal);
}

.nav-item:hover {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.12) 0%, rgba(236, 72, 153, 0.08) 100%);
    transform: translateX(8px) scale(1.02);
    box-shadow: var(--shadow-md), 0 0 20px rgba(99, 102, 241, 0.15);
    border-color: rgba(99, 102, 241, 0.2);
    color: var(--text-primary);
}

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

.nav-item:hover::after {
    transform: translateX(0);
}

.nav-item.active {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(236, 72, 153, 0.1) 100%);
    font-weight: 700;
    color: var(--primary-color);
    box-shadow: var(--shadow-md), 0 0 24px rgba(99, 102, 241, 0.2);
    border-color: rgba(99, 102, 241, 0.3);
}

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

.nav-icon {
    font-size: 1.8rem;
    transition: transform var(--transition-normal);
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.nav-item:hover .nav-icon {
    transform: scale(1.3) rotate(15deg);
    filter: drop-shadow(0 4px 8px rgba(99, 102, 241, 0.3));
}

.nav-item.active .nav-icon {
    animation: iconBounce 0.8s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

@keyframes iconBounce {
    0%, 100% { transform: scale(1) rotate(0deg); }
    25% { transform: scale(1.3) rotate(-10deg); }
    75% { transform: scale(1.3) rotate(10deg); }
}

/* =============================================
   MAIN CONTENT AREA
   ============================================= */

.content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 48px 64px;
    max-width: 1600px;
    position: relative;
    z-index: 2;
}

/* Tab Content */
.tab-content {
    display: none;
    animation: contentReveal 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.tab-content.active {
    display: block;
}

@keyframes contentReveal {
    from {
        opacity: 0;
        transform: translateY(40px) scale(0.98);
        filter: blur(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
        filter: blur(0);
    }
}

/* =============================================
   TYPOGRAPHY - Premium with Dark Text
   ============================================= */

h1 {
    font-family: 'Playfair Display', serif;
    font-size: 4.5rem;
    font-weight: 900;
    background: linear-gradient(135deg, #6366f1 0%, #ec4899 50%, #f59e0b 100%);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 24px;
    letter-spacing: -0.03em;
    line-height: 1.1;
    animation: titleGradient 8s ease infinite;
    filter: drop-shadow(0 4px 12px rgba(99, 102, 241, 0.2));
}

@keyframes titleGradient {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

h2 {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 20px;
    letter-spacing: -0.02em;
}

h3 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.section-intro {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 48px;
    max-width: 900px;
    line-height: 1.8;
    font-weight: 500;
}

/* =============================================
   HOME TAB - Ultra Premium Light Theme
   ============================================= */

.home-hero {
    text-align: center;
    padding: 80px 0;
    position: relative;
}

.main-title {
    font-size: 5.5rem;
    background: linear-gradient(135deg, #6366f1 0%, #ec4899 25%, #f59e0b 50%, #06b6d4 75%, #a855f7 100%);
    background-size: 300% 300%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 16px;
    animation: epicGradient 10s ease infinite;
    letter-spacing: -0.04em;
    font-weight: 900;
    filter: drop-shadow(0 4px 16px rgba(99, 102, 241, 0.25));
}

@keyframes epicGradient {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.author-line {
    font-size: 1.4rem;
    color: var(--text-secondary);
    margin-bottom: 56px;
    font-weight: 600;
}

.welcome-box {
    background: linear-gradient(135deg, 
        rgba(99, 102, 241, 0.95) 0%, 
        rgba(168, 85, 247, 0.95) 50%,
        rgba(236, 72, 153, 0.95) 100%);
    backdrop-filter: blur(30px) saturate(180%);
    -webkit-backdrop-filter: blur(30px) saturate(180%);
    color: white;
    padding: 56px 64px;
    border-radius: var(--border-radius-lg);
    max-width: 850px;
    margin: 0 auto 72px;
    box-shadow: var(--shadow-xl), var(--shadow-neon);
    position: relative;
    overflow: hidden;
    border: 3px solid rgba(255, 255, 255, 0.4);
    transform-style: preserve-3d;
    transition: transform var(--transition-normal);
}

.welcome-box:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-xl), var(--shadow-neon-hover);
}

.welcome-box::before {
    content: '';
    position: absolute;
    top: -100%;
    left: -100%;
    width: 300%;
    height: 300%;
    background: conic-gradient(from 0deg, transparent, rgba(255, 255, 255, 0.4), transparent 30%);
    animation: conicRotate 6s linear infinite;
}

@keyframes conicRotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.welcome-box::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.15) 0%, transparent 70%);
    animation: pulseGlow 4s ease-in-out infinite;
}

@keyframes pulseGlow {
    0%, 100% { opacity: 0.5; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.05); }
}

.welcome-box h2 {
    color: white;
    margin-bottom: 24px;
    position: relative;
    z-index: 1;
    font-size: 2.8rem;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.welcome-box p {
    margin-bottom: 16px;
    font-size: 1.25rem;
    position: relative;
    z-index: 1;
    line-height: 1.8;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.quick-start {
    max-width: 1200px;
    margin: 0 auto;
}

.quick-start h3 {
    margin-bottom: 40px;
    color: var(--text-primary);
    font-size: 2.2rem;
}

.start-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.start-card {
    background: white;
    backdrop-filter: blur(20px);
    padding: 48px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    transition: all var(--transition-normal) cubic-bezier(0.4, 0, 0.2, 1);
    border: 3px solid rgba(99, 102, 241, 0.15);
    position: relative;
    overflow: hidden;
}

.start-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(236, 72, 153, 0.08) 100%);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.start-card:hover::before {
    opacity: 1;
}

.start-card:hover {
    transform: translateY(-16px) scale(1.05);
    box-shadow: var(--shadow-xl), var(--shadow-neon);
    border-color: var(--primary-color);
}

.card-icon {
    font-size: 5rem;
    display: block;
    margin-bottom: 28px;
    transition: transform var(--transition-normal);
    position: relative;
    z-index: 1;
    filter: drop-shadow(0 8px 16px rgba(0, 0, 0, 0.15));
}

.start-card:hover .card-icon {
    transform: scale(1.3) rotate(20deg);
    filter: drop-shadow(0 12px 24px rgba(99, 102, 241, 0.3));
}

.start-card h4 {
    font-size: 1.8rem;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-pink) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    position: relative;
    z-index: 1;
}

.start-card p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.7;
    position: relative;
    z-index: 1;
}

/* =============================================
   CONCEPT CARDS - Premium Light Design
   ============================================= */

.diagram-container {
    background: white;
    backdrop-filter: blur(20px);
    padding: 56px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    margin-bottom: 56px;
    border: 3px solid rgba(99, 102, 241, 0.15);
    transition: all var(--transition-normal);
}

.diagram-container:hover {
    box-shadow: var(--shadow-xl), var(--shadow-neon);
    transform: translateY(-4px);
    border-color: var(--primary-color);
}

.diagram-container h3 {
    text-align: center;
    margin-bottom: 40px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-cyan) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 2.2rem;
}

.flow-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 28px;
    flex-wrap: wrap;
}

.flow-box {
    background: white;
    padding: 36px 40px;
    border-radius: var(--border-radius);
    text-align: center;
    min-width: 200px;
    border: 4px solid #e2e8f0;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.flow-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.9), transparent);
    transition: left 0.6s;
}

.flow-box:hover::before {
    left: 100%;
}

.flow-box:hover {
    transform: translateY(-12px) scale(1.08);
    box-shadow: var(--shadow-xl), 0 0 40px rgba(99, 102, 241, 0.2);
}

.flow-box.input-box {
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    border-color: #3b82f6;
}

.flow-box.process-box {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    border-color: #f59e0b;
}

.flow-box.output-box {
    background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
    border-color: #10b981;
}

.flow-icon {
    font-size: 3.5rem;
    display: block;
    margin-bottom: 16px;
    animation: iconFloat 4s ease-in-out infinite;
    filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.15));
}

@keyframes iconFloat {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(5deg); }
}

.flow-box strong {
    display: block;
    font-size: 1.3rem;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-weight: 700;
}

.flow-box p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.flow-arrow {
    font-size: 3.5rem;
    color: var(--primary-color);
    font-weight: bold;
    animation: arrowPulse 2s ease-in-out infinite;
    filter: drop-shadow(0 0 20px rgba(99, 102, 241, 0.4));
}

@keyframes arrowPulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.7; transform: scale(1.3); }
}

.concept-grid {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.concept-card {
    background: white;
    backdrop-filter: blur(20px);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
    border: 3px solid rgba(99, 102, 241, 0.15);
}

.concept-card:hover {
    box-shadow: var(--shadow-xl), var(--shadow-neon);
    transform: translateY(-8px) scale(1.01);
    border-color: var(--primary-color);
}

.concept-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-pink) 100%);
    color: white;
    padding: 32px 36px;
    display: flex;
    align-items: center;
    gap: 24px;
    position: relative;
    overflow: hidden;
}

.concept-header::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 100%;
    height: 200%;
    background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transform: rotate(45deg);
    animation: headerShine 4s infinite;
}

@keyframes headerShine {
    0% { transform: translateX(-200%) rotate(45deg); }
    100% { transform: translateX(200%) rotate(45deg); }
}

.concept-icon {
    font-size: 3.5rem;
    filter: drop-shadow(0 4px 12px rgba(0, 0, 0, 0.3));
    animation: iconBreathe 3s ease-in-out infinite;
}

@keyframes iconBreathe {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.concept-header h2 {
    color: white;
    margin: 0;
    font-size: 1.8rem;
    position: relative;
    z-index: 1;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.concept-body {
    padding: 40px;
}

.concept-body h3 {
    color: var(--text-primary);
    margin-bottom: 16px;
}

.concept-body p {
    margin-bottom: 20px;
    line-height: 1.8;
    font-size: 1.05rem;
    color: var(--text-secondary);
}

.concept-body strong {
    color: var(--text-primary);
    font-weight: 700;
}

.examples-box {
    background: linear-gradient(135deg, #ede9fe 0%, #ddd6fe 100%);
    padding: 32px;
    border-radius: 16px;
    margin-top: 24px;
    border-left: 6px solid var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.examples-box h4 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.4rem;
}

.examples-box ul {
    list-style: none;
}

.examples-box li {
    padding: 16px 12px;
    border-bottom: 2px solid rgba(99, 102, 241, 0.15);
    transition: all var(--transition-fast);
    padding-left: 12px;
    font-size: 1.05rem;
    color: var(--text-secondary);
}

.examples-box li:hover {
    background: rgba(99, 102, 241, 0.1);
    padding-left: 24px;
    border-radius: 8px;
    transform: translateX(8px);
    color: var(--text-primary);
}

.examples-box li:last-child {
    border-bottom: none;
}

.did-you-know {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    padding: 32px;
    border-radius: 16px;
    margin-top: 24px;
    border-left: 6px solid var(--accent-orange);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.did-you-know::before {
    content: '💡';
    position: absolute;
    top: 16px;
    right: 16px;
    font-size: 4rem;
    opacity: 0.3;
    animation: bulbGlow 2s ease-in-out infinite;
}

@keyframes bulbGlow {
    0%, 100% { opacity: 0.3; transform: scale(1); }
    50% { opacity: 0.6; transform: scale(1.1); }
}

.did-you-know strong {
    color: #92400e;
    font-size: 1.2rem;
}

.did-you-know p {
    color: #78350f;
}

/* =============================================
   BUTTONS - Premium 3D
   ============================================= */

button, .btn {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-pink) 100%);
    color: white;
    border: none;
    padding: 18px 40px;
    border-radius: 16px;
    font-size: 1.15rem;
    font-weight: 700;
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

button::before, .btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.4);
    transform: translate(-50%, -50%);
    transition: width 0.8s, height 0.8s;
}

button:hover::before, .btn:hover::before {
    width: 400px;
    height: 400px;
}

button:hover, .btn:hover {
    transform: translateY(-4px) scale(1.05);
    box-shadow: var(--shadow-xl), var(--shadow-neon);
}

button:active, .btn:active {
    transform: translateY(-2px) scale(1.02);
}

button:disabled, .btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* =============================================
   RESPONSIVE DESIGN
   ============================================= */

@media (max-width: 1024px) {
    .content {
        padding: 40px 48px;
    }
    
    .main-title {
        font-size: 4rem;
    }
    
    h1 {
        font-size: 3.5rem;
    }
}

@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
        border-right: none;
        border-bottom: 2px solid rgba(99, 102, 241, 0.15);
    }
    
    .content {
        margin-left: 0;
        padding: 32px 24px;
    }
    
    .nav-menu {
        display: flex;
        flex-wrap: wrap;
        gap: 12px;
    }
    
    .nav-item {
        flex: 1;
        min-width: 140px;
        justify-content: center;
    }
    
    .main-title {
        font-size: 3rem;
    }
    
    h1 {
        font-size: 2.5rem;
    }
    
    .welcome-box {
        padding: 40px 32px;
    }
    
    .start-cards {
        grid-template-columns: 1fr;
    }
    
    .flow-diagram {
        flex-direction: column;
    }
    
    .flow-arrow {
        transform: rotate(90deg);
    }
}

/* =============================================
   SCROLLBAR - Premium
   ============================================= */

::-webkit-scrollbar {
    width: 14px;
    height: 14px;
}

::-webkit-scrollbar-track {
    background: rgba(241, 245, 249, 0.8);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-pink) 100%);
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(99, 102, 241, 0.3);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--accent-purple) 100%);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.5);
}

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

/* =============================================
   UTILITY CLASSES
   ============================================= */

.hidden {
    display: none !important;
}

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