/* ==========================================
   DESIGN SYSTEM & CUSTOM PROPERTIES
   ========================================== */

:root {
    /* Color Palette - Light Mode Default */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-card: rgba(255, 255, 255, 0.8);
    --border-color: rgba(226, 232, 240, 0.8);
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    
    --accent-color: #3b82f6;
    --accent-hover: #1d4ed8;
    --accent-rgb: 59, 130, 246;
    
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    
    --gradient-hero: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
    --gradient-accent: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
    --gradient-text: linear-gradient(135deg, #3b82f6 0%, #2ec4b6 100%);
    --gradient-glow: rgba(59, 130, 246, 0.15);
    
    --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 -4px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.11);
    
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-full: 9999px;
    
    --font-primary: 'Outfit', 'Noto Sans KR', sans-serif;
}

/* Dark Mode Palette Variables */
[data-theme="dark"] {
    --bg-primary: #090d16;
    --bg-secondary: #111827;
    --bg-card: rgba(17, 24, 39, 0.7);
    --border-color: rgba(255, 255, 255, 0.08);
    
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --accent-color: #60a5fa;
    --accent-hover: #3b82f6;
    --accent-rgb: 96, 165, 250;
    
    --gradient-hero: linear-gradient(135deg, #1e1b4b 0%, #0f172a 100%);
    --gradient-accent: linear-gradient(135deg, #60a5fa 0%, #c084fc 100%);
    --gradient-text: linear-gradient(135deg, #60a5fa 0%, #4ade80 100%);
    --gradient-glow: rgba(96, 165, 250, 0.2);
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 24px 38px -5px rgba(0, 0, 0, 0.5), 0 8px 24px -6px rgba(0, 0, 0, 0.4);
}

/* ==========================================
   RESET & GLOBAL STYLES
   ========================================== */

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color 0.4s ease, color 0.4s ease;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Background Glow Effects */
.glow-bg-1, .glow-bg-2 {
    position: absolute;
    width: 45vw;
    height: 45vw;
    border-radius: var(--radius-full);
    filter: blur(140px);
    z-index: -1;
    opacity: 0.3;
    pointer-events: none;
    transition: all 0.4s ease;
}

.glow-bg-1 {
    top: -10vw;
    right: -10vw;
    background: radial-gradient(circle, var(--gradient-glow) 0%, transparent 70%);
}

.glow-bg-2 {
    top: 50vw;
    left: -10vw;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.15) 0%, transparent 70%);
}

/* ==========================================
   TYPOGRAPHY & UTILITIES
   ========================================== */

h1, h2, h3, h4 {
    font-weight: 700;
    line-height: 1.25;
}

.gradient-text {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.badge {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(var(--accent-rgb), 0.12);
    color: var(--accent-color);
    font-size: 0.85rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    margin-bottom: 16px;
    border: 1px solid rgba(var(--accent-rgb), 0.2);
}

.section-badge {
    display: inline-block;
    padding: 6px 16px;
    background: var(--border-color);
    color: var(--text-secondary);
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ==========================================
   BUTTONS
   ========================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    font-family: var(--font-primary);
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    text-decoration: none;
    border: 1px solid transparent;
    gap: 8px;
}

.btn-sm {
    padding: 8px 18px;
    font-size: 0.875rem;
    border-radius: var(--radius-sm);
}

.btn-lg {
    padding: 16px 32px;
    font-size: 1.125rem;
}

.btn-xl {
    padding: 20px 40px;
    font-size: 1.25rem;
    border-radius: var(--radius-md);
}

.btn-block {
    display: flex;
    width: 100%;
}

.btn-primary {
    background: var(--gradient-accent);
    color: #ffffff;
    box-shadow: 0 10px 15px -3px rgba(var(--accent-rgb), 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 20px -3px rgba(var(--accent-rgb), 0.4);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    background: var(--bg-primary);
    transform: translateY(-2px);
}

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

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

.btn-accent {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    box-shadow: 0 10px 15px -3px rgba(16, 185, 129, 0.3);
}

.btn-accent:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 20px -3px rgba(16, 185, 129, 0.4);
}

/* Animations */
@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(var(--accent-rgb), 0.4);
    }
    70% {
        box-shadow: 0 0 0 15px rgba(var(--accent-rgb), 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(var(--accent-rgb), 0);
    }
}

.pulse-animation {
    animation: pulse 2s infinite;
}

/* ==========================================
   HEADER / NAVIGATION
   ========================================== */

.main-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 80px;
    z-index: 100;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    background-color: rgba(var(--bg-primary) == #090d16 ? '9, 13, 22' : '248, 250, 252', 0.85);
    display: flex;
    align-items: center;
    transition: background-color 0.4s ease, border-color 0.4s ease;
}

/* Clean background opacity matching */
body.light-theme .main-header {
    background-color: rgba(248, 250, 252, 0.8);
}
[data-theme="dark"] .main-header {
    background-color: rgba(9, 13, 22, 0.8);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.logo-accent {
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s ease;
}

.nav-links a:hover {
    color: var(--accent-color);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.theme-toggle-btn {
    background: none;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    border: 1px solid var(--border-color);
    transition: all 0.3s;
}

.theme-toggle-btn:hover {
    background: var(--border-color);
}

/* ==========================================
   HERO SECTION
   ========================================== */

.hero-section {
    padding-top: 180px;
    padding-bottom: 100px;
    position: relative;
}

.hero-container {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 64px;
    align-items: center;
}

.hero-text-content {
    display: flex;
    flex-direction: column;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    line-height: 1.6;
}

.book-meta-inline {
    display: flex;
    flex-wrap: wrap;
    gap: 24px;
    margin-bottom: 32px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
}

.meta-item {
    font-size: 0.95rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.meta-item i {
    color: var(--accent-color);
    font-size: 1.1rem;
}

.hero-pricing {
    margin-bottom: 32px;
}

.price-box {
    display: flex;
    align-items: baseline;
    gap: 12px;
}

.original-price {
    font-size: 1.25rem;
    text-decoration: line-through;
    color: var(--text-muted);
}

.current-price {
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-primary);
}

.current-price .currency {
    font-size: 1.5rem;
    font-weight: 700;
}

.discount-badge {
    padding: 4px 10px;
    background-color: var(--danger-color);
    color: white;
    font-size: 0.85rem;
    font-weight: 700;
    border-radius: var(--radius-sm);
    transform: translateY(-8px);
}

.hero-cta-group {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* 3D BOOK COVER MOCKUP */
.hero-image-content {
    display: flex;
    justify-content: center;
    align-items: center;
    perspective: 1200px;
}

.book-mockup-wrapper {
    position: relative;
    width: 320px;
    height: 450px;
    transform-style: preserve-3d;
    transition: transform 0.5s ease;
}

.book-card-3d {
    width: 100%;
    height: 100%;
    position: relative;
    transform-style: preserve-3d;
    transform: rotateY(-18deg) rotateX(10deg);
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.book-mockup-wrapper:hover .book-card-3d {
    transform: rotateY(-5deg) rotateX(5deg) scale(1.03);
}

.book-cover-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 4px 12px 12px 4px;
    box-shadow: 10px 10px 30px rgba(0, 0, 0, 0.35);
    position: absolute;
    top: 0;
    left: 0;
    z-index: 2;
    backface-visibility: hidden;
}

.book-cover-side {
    position: absolute;
    top: 2%;
    left: -20px;
    width: 20px;
    height: 96%;
    background: #e2a014; /* Banana color spine */
    background: linear-gradient(90deg, #b87b07 0%, #f1b51e 100%);
    transform: rotateY(-90deg);
    transform-origin: right center;
    z-index: 1;
    border-radius: 4px 0 0 4px;
}

.shadow-3d {
    position: absolute;
    bottom: -30px;
    left: 5%;
    width: 90%;
    height: 25px;
    background: radial-gradient(ellipse at center, rgba(0,0,0,0.4) 0%, rgba(0,0,0,0) 80%);
    filter: blur(5px);
    z-index: 0;
    transition: all 0.5s;
}

.book-mockup-wrapper:hover .shadow-3d {
    transform: scale(1.08);
    opacity: 0.8;
}

/* ==========================================
   FEATURES SECTION
   ========================================== */

.features-section {
    padding: 100px 0;
    position: relative;
}

.section-header {
    text-align: center;
    max-width: 650px;
    margin: 0 auto 60px auto;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: 1.05rem;
    color: var(--text-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    padding: 40px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

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

.card-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    margin-bottom: 24px;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.card-desc {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.975rem;
}

/* ==========================================
   AUDIENCE SECTION
   ========================================== */

.audience-section {
    padding: 100px 0;
    background-color: var(--bg-secondary);
    transition: background-color 0.4s ease;
}

.audience-container {
    display: grid;
    grid-template-columns: 0.9fr 1.1fr;
    gap: 64px;
    align-items: center;
}

.audience-image-side {
    position: relative;
    height: 380px;
    background: var(--gradient-accent);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
}

/* Overlay high-tech mesh design on the placeholder cover area */
.audience-image-side::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: radial-gradient(circle at 80% 20%, rgba(255,255,255,0.15) 0%, transparent 60%),
                linear-gradient(210deg, rgba(59,130,246,0.3) 0%, rgba(139,92,246,0) 70%);
    z-index: 1;
}

.mascot-badge-box {
    position: absolute;
    bottom: 30px;
    left: 30px;
    right: 30px;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.25);
    padding: 24px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: 20px;
    z-index: 2;
}

.icon-avatar {
    width: 50px;
    height: 50px;
    border-radius: var(--radius-full);
    background: #fef08a; /* Yellow glow */
    color: #b45309;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    flex-shrink: 0;
    box-shadow: 0 0 15px rgba(254, 240, 138, 0.6);
}

.mascot-text h4 {
    color: #ffffff;
    font-size: 1.05rem;
    margin-bottom: 4px;
}

.mascot-text p {
    color: rgba(255, 255, 255, 0.85);
    font-size: 0.85rem;
}

.audience-text-side {
    display: flex;
    flex-direction: column;
}

.audience-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 24px;
    margin-top: 32px;
}

.audience-list li {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.audience-list li i {
    color: var(--success-color);
    font-size: 1.5rem;
    margin-top: 2px;
}

.audience-list li strong {
    display: block;
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.audience-list li p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* ==========================================
   DETAILS SECTION
   ========================================== */

.details-section {
    padding: 100px 0;
}

.details-card-wrapper {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.details-left {
    padding: 60px;
    border-right: 1px solid var(--border-color);
}

.details-left h3 {
    font-size: 1.75rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.details-left > p {
    color: var(--text-secondary);
    margin-bottom: 40px;
}

.spec-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.spec-item {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.spec-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.spec-value {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
}

.details-right {
    padding: 60px;
    background: rgba(var(--accent-rgb), 0.02);
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 32px;
}

.guarantee-box {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.guarantee-icon {
    font-size: 2rem;
    color: var(--accent-color);
}

.guarantee-box h4 {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-primary);
}

.guarantee-box p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* ==========================================
   PURCHASE CARD SECTION
   ========================================== */

.purchase-section {
    padding: 100px 0;
    position: relative;
}

.purchase-card {
    background: var(--bg-card);
    border: 1px solid var(--accent-color);
    border-radius: var(--radius-lg);
    padding: 60px;
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 60px;
    align-items: center;
    box-shadow: 0 20px 40px -10px rgba(var(--accent-rgb), 0.15);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

/* Decorative backdrop glow inside buy card */
.purchase-card::after {
    content: '';
    position: absolute;
    right: -100px;
    bottom: -100px;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(var(--accent-rgb), 0.1) 0%, transparent 70%);
    z-index: -1;
}

.discount-pill {
    display: inline-block;
    padding: 6px 14px;
    background: var(--danger-color);
    color: white;
    font-size: 0.8rem;
    font-weight: 700;
    border-radius: var(--radius-full);
    margin-bottom: 20px;
}

.purchase-title {
    font-size: 2.25rem;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.purchase-desc {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 32px;
}

.pricing-display {
    display: flex;
    gap: 40px;
}

.price-col {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.price-tag {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
}

.price-val {
    font-size: 1.5rem;
    font-weight: 700;
}

.price-val.strike {
    text-decoration: line-through;
    color: var(--text-muted);
}

.text-accent .price-val {
    font-size: 2.75rem;
    font-weight: 900;
    color: var(--accent-color);
}

.purchase-action {
    display: flex;
    flex-direction: column;
    gap: 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 40px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.guarantees-list {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 600;
    margin-bottom: 8px;
}

.guarantees-list span {
    display: flex;
    align-items: center;
    gap: 6px;
}

.guarantees-list i {
    color: var(--accent-color);
}

.action-note {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-align: center;
}

/* ==========================================
   FAQ ACCORDION SECTION
   ========================================== */

.faq-section {
    padding: 100px 0;
}

.faq-accordion {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color 0.3s;
}

.faq-item.active {
    border-color: var(--accent-color);
}

.faq-question {
    width: 100%;
    padding: 24px;
    background: none;
    border: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-align: left;
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    gap: 20px;
}

.faq-question i {
    color: var(--text-muted);
    transition: transform 0.3s;
    font-size: 1rem;
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
    color: var(--accent-color);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    background: rgba(var(--accent-rgb), 0.01);
}

.faq-answer p {
    padding: 0 24px 24px 24px;
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.975rem;
}

/* ==========================================
   FOOTER
   ========================================== */

.main-footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 80px 0 40px 0;
    transition: background-color 0.4s ease;
}

.footer-container {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
}

.footer-brand .logo {
    display: inline-block;
    margin-bottom: 16px;
}

.footer-brand p {
    color: var(--text-secondary);
    max-width: 400px;
    font-size: 0.95rem;
}

.footer-contacts h4 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.footer-contacts p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-contacts i {
    color: var(--accent-color);
}

.footer-bottom {
    grid-column: span 2;
    margin-top: 48px;
    padding-top: 32px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ==========================================
   MODAL DIALOG (PAYMENT SIMULATION)
   ========================================== */

.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(9, 13, 22, 0.6);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal-backdrop.show {
    opacity: 1;
    pointer-events: auto;
}

.modal-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 480px;
    box-shadow: var(--shadow-xl);
    position: relative;
    overflow: hidden;
    transform: translateY(30px);
    transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.modal-backdrop.show .modal-card {
    transform: translateY(0);
}

.modal-close-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: color 0.2s;
    z-index: 10;
}

.modal-close-btn:hover {
    color: var(--text-primary);
}

.modal-header {
    padding: 40px 40px 20px 40px;
    text-align: center;
}

.modal-icon-badge {
    width: 64px;
    height: 64px;
    border-radius: var(--radius-full);
    background: rgba(var(--accent-rgb), 0.1);
    color: var(--accent-color);
    font-size: 1.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px auto;
}

.modal-header h3 {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.modal-header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.modal-body {
    padding: 0 40px 40px 40px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 24px;
}

.form-group label {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-primary);
}

.form-group input {
    width: 100%;
    padding: 14px 18px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(var(--accent-rgb), 0.15);
}

.form-helper {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.modal-pricing-box {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-primary);
    padding: 18px;
    border-radius: var(--radius-md);
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
}

.m-price-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.m-price-value {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--accent-color);
}

.info-alert {
    background: rgba(var(--accent-rgb), 0.05);
    border: 1px solid rgba(var(--accent-rgb), 0.15);
    color: var(--text-secondary);
    padding: 14px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    display: flex;
    gap: 10px;
    align-items: flex-start;
    margin-bottom: 24px;
    line-height: 1.5;
}

.info-alert i {
    color: var(--accent-color);
    font-size: 1.1rem;
    margin-top: 2px;
    flex-shrink: 0;
}

/* ==========================================
   RESPONSIVE DESIGN (MEDIA QUERIES)
   ========================================== */

@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 48px;
        text-align: center;
    }
    
    .hero-text-content {
        align-items: center;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .book-meta-inline {
        justify-content: center;
    }
    
    .hero-pricing {
        justify-content: center;
        display: flex;
    }
    
    .hero-cta-group {
        justify-content: center;
    }
    
    .audience-container {
        grid-template-columns: 1fr;
        gap: 48px;
    }
    
    .audience-image-side {
        height: 300px;
    }
    
    .details-card-wrapper {
        grid-template-columns: 1fr;
    }
    
    .details-left {
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    .purchase-card {
        grid-template-columns: 1fr;
        gap: 40px;
        padding: 40px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none; /* Hide nav links on mobile for clean look, keep CTA and theme */
    }
    
    .hero-title {
        font-size: 2.25rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .spec-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .footer-container {
        grid-template-columns: 1fr;
    }
    
    .footer-bottom {
        grid-column: span 1;
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }
}