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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #10b981;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #111827;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header & Navigation */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--primary-color);
}

.nav-brand i {
    font-size: 1.5rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

.nav-cta {
    background: var(--primary-color) !important;
    color: white !important;
    padding: 10px 20px;
    border-radius: 6px;
    transition: all 0.3s ease;
}

.nav-cta:hover {
    background: var(--primary-dark) !important;
    transform: translateY(-1px);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger .bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    overflow: hidden;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

.hero-title .highlight {
    background: linear-gradient(45deg, #fbbf24, #f59e0b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.7;
}

.hero-stats {
    display: flex;
    gap: 2rem;
    margin-bottom: 2.5rem;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: #fbbf24;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.8;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn-primary, .btn-secondary {
    padding: 16px 32px;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

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

.btn-primary:hover {
    background: #059669;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

/* Book Mockup */
.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.book-mockup {
    perspective: 1000px;
}

.book-cover {
    width: 300px;
    height: 400px;
    background: linear-gradient(145deg, #1f2937, #374151);
    border-radius: 12px;
    padding: 40px 30px;
    box-shadow: var(--shadow-xl);
    transform: rotateY(-15deg) rotateX(5deg);
    transition: transform 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    color: white;
    position: relative;
    overflow: hidden;
}

.book-cover::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, rgba(37, 99, 235, 0.1), rgba(16, 185, 129, 0.1));
    z-index: 1;
}

.book-cover > * {
    position: relative;
    z-index: 2;
}

.book-cover:hover {
    transform: rotateY(-10deg) rotateX(2deg) scale(1.05);
}

.book-title {
    font-size: 2.5rem;
    font-weight: 900;
    line-height: 1;
    text-align: center;
}

.book-title span {
    color: #fbbf24;
    font-size: 1.5rem;
}

.book-subtitle {
    font-size: 1rem;
    text-align: center;
    color: #9ca3af;
    margin: 20px 0;
}

.book-author {
    font-size: 0.9rem;
    text-align: center;
    color: #6b7280;
}

/* Features Section */
.features {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.section-header p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2rem;
    color: white;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Contents Section */
.contents {
    padding: 100px 0;
}

.contents-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    max-width: 1000px;
    margin: 0 auto;
}

.chapter {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
}

.chapter:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(5px);
}

.chapter-number {
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
}

.chapter-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

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

/* Testimonials Section */
.testimonials {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.testimonial-card {
    background: white;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

.testimonial-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.stars {
    display: flex;
    gap: 4px;
    margin-bottom: 1.5rem;
    color: #fbbf24;
}

.testimonial-content p {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-style: italic;
}

.author-info h4 {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.author-info span {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Pricing Section */
.pricing {
    padding: 100px 0;
    background: var(--bg-primary);
}

.pricing-card {
    max-width: 500px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    text-align: center;
}

.price-tag {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 3rem 2rem;
}

.price {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.currency {
    font-size: 2rem;
    font-weight: 600;
}

.amount {
    font-size: 4rem;
    font-weight: 900;
}

.price-description {
    font-size: 1.1rem;
    opacity: 0.9;
}

.included-items {
    padding: 2.5rem;
    text-align: left;
}

.included-items h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--text-primary);
}

.included-items ul {
    list-style: none;
    margin-bottom: 2rem;
}

.included-items li {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.included-items li i {
    color: var(--secondary-color);
    font-size: 1.2rem;
}

.purchase-section {
    padding: 0 2.5rem 2.5rem;
}

.btn-purchase {
    width: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 20px;
    border-radius: 10px;
    font-size: 1.25rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 1.5rem;
}

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

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

.payment-info p {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

/* FAQ Section */
.faq {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.faq-grid {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: white;
    border-radius: 12px;
    margin-bottom: 1rem;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.faq-question {
    padding: 1.5rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
}

.faq-question:hover {
    background: var(--bg-secondary);
}

.faq-question h4 {
    font-weight: 600;
    color: var(--text-primary);
}

.faq-question i {
    color: var(--text-light);
    transition: transform 0.3s ease;
}

.faq-answer {
    padding: 0 1.5rem 1.5rem;
    color: var(--text-secondary);
    line-height: 1.7;
    display: none;
}

.faq-item.active .faq-answer {
    display: block;
}

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

/* Footer */
.footer {
    background: var(--bg-dark);
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.25rem;
}

.footer-brand i {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #374151;
    color: #9ca3af;
}

/* Responsive Design */
@media (max-width: 968px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-md);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .hamburger {
        display: flex;
    }

    .hero-content {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-stats {
        justify-content: center;
    }

    .contents-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .footer-content {
        flex-direction: column;
        gap: 2rem;
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .hero {
        padding: 100px 0 60px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-description {
        font-size: 1.1rem;
    }

    .hero-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .hero-cta {
        flex-direction: column;
    }

    .book-cover {
        width: 250px;
        height: 320px;
        padding: 30px 20px;
    }

    .book-title {
        font-size: 2rem;
    }

    .features-grid,
    .testimonials-grid {
        grid-template-columns: 1fr;
    }

    .feature-card,
    .testimonial-card {
        padding: 2rem;
    }

    .section-header h2 {
        font-size: 2rem;
    }

    .section-header p {
        font-size: 1.1rem;
    }

    .chapter {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }

    .chapter-number {
        align-self: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero {
        padding: 90px 0 50px;
    }

    .hero-title {
        font-size: 1.75rem;
    }

    .btn-primary,
    .btn-secondary {
        padding: 14px 24px;
        font-size: 1rem;
    }

    .book-cover {
        width: 200px;
        height: 280px;
        padding: 25px 15px;
    }

    .book-title {
        font-size: 1.5rem;
    }

    .features,
    .contents,
    .testimonials,
    .pricing,
    .faq {
        padding: 60px 0;
    }

    .feature-card,
    .testimonial-card {
        padding: 1.5rem;
    }

    .pricing-card {
        margin: 0 15px;
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Loading animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feature-card,
.testimonial-card,
.chapter {
    animation: fadeInUp 0.6s ease-out;
}

/* Utility classes */
.text-center {
    text-align: center;
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }