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

:root {
    /* Colors from book cover */
    --primary-blue: #4A90E2;
    --dark-blue: #2C5282;
    --cream: #F5F2E8;
    --off-white: #FAFAF8;
    --dark-text: #1A202C;
    --gray-text: #4A5568;
    --light-gray: #E2E8F0;
    --accent-gold: #D69E2E;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-base: 16px;
    --line-height-base: 1.6;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 3rem;
    --spacing-xl: 4rem;
    --spacing-xxl: 6rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1), 0 2px 4px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.1), 0 10px 10px rgba(0,0,0,0.04);
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--dark-text);
    background-color: var(--off-white);
    overflow-x: hidden;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-blue);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--dark-text);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--primary-blue);
}

.nav-link.cta-button {
    background: var(--primary-blue);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 6px;
    transition: all 0.3s ease;
}

.nav-link.cta-button:hover {
    background: var(--dark-blue);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

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

/* Hero Section */
.hero {
    padding: calc(var(--spacing-xxl) + 80px) 0 var(--spacing-xxl);
    background: linear-gradient(135deg, var(--off-white) 0%, var(--cream) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: var(--dark-text);
}

.hero-title .highlight {
    color: var(--primary-blue);
    position: relative;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--gray-text);
    margin-bottom: var(--spacing-lg);
}

.hero-features {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.feature-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.feature-icon {
    width: 20px;
    height: 20px;
    color: var(--primary-blue);
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: var(--primary-blue);
    color: white;
    box-shadow: var(--shadow-md);
}

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

.btn-secondary {
    background: transparent;
    color: var(--primary-blue);
    border: 2px solid var(--primary-blue);
}

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

.btn-large {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.125rem;
}

.hero-image {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.book-cover {
    width: 100%;
    max-width: 400px;
    height: auto;
    border-radius: 8px;
    box-shadow: var(--shadow-xl);
    transition: transform 0.3s ease;
}

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

.book-shadow {
    position: absolute;
    bottom: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 80%;
    height: 20px;
    background: rgba(0,0,0,0.2);
    filter: blur(20px);
    border-radius: 50%;
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    color: var(--dark-text);
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    font-size: 1.25rem;
    color: var(--gray-text);
}

/* About Book Section */
.about-book {
    padding: var(--spacing-xxl) 0;
    background: white;
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.about-card {
    text-align: center;
    padding: var(--spacing-lg);
    border-radius: 12px;
    background: var(--off-white);
    transition: all 0.3s ease;
}

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

.card-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--primary-blue);
    color: white;
    border-radius: 12px;
}

.card-icon svg {
    width: 100%;
    height: 100%;
}

.about-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--dark-text);
}

.about-card p {
    color: var(--gray-text);
    line-height: 1.8;
}

/* Chapters Section */
.chapters {
    padding: var(--spacing-xxl) 0;
    background: linear-gradient(to bottom, white, var(--cream));
}

.chapters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.chapter-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

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

.chapter-card.featured {
    background: var(--primary-blue);
    color: white;
}

.chapter-card.featured .chapter-number {
    color: white;
    opacity: 0.2;
}

.chapter-card.featured h3,
.chapter-card.featured p {
    color: white;
}

.chapter-card.featured .chapter-link {
    color: white;
    border-color: white;
}

.chapter-number {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary-blue);
    opacity: 0.1;
}

.chapter-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--dark-text);
    position: relative;
    z-index: 1;
}

.chapter-card p {
    color: var(--gray-text);
    margin-bottom: var(--spacing-md);
    position: relative;
    z-index: 1;
}

.chapter-link {
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    transition: all 0.3s ease;
    position: relative;
    z-index: 1;
}

.chapter-link:hover {
    transform: translateX(5px);
}

/* Author Section */
.author {
    padding: var(--spacing-xxl) 0;
    background: white;
}

.author-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.author-text {
    font-size: 1.125rem;
    color: var(--gray-text);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

.author-credentials {
    display: flex;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.credential {
    text-align: center;
}

.credential strong {
    display: block;
    font-size: 2rem;
    color: var(--primary-blue);
    font-weight: 800;
}

.credential span {
    font-size: 0.875rem;
    color: var(--gray-text);
}

.author-placeholder {
    width: 300px;
    height: 300px;
    background: var(--light-gray);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
}

.author-placeholder svg {
    width: 150px;
    height: 150px;
    color: var(--gray-text);
}

/* Testimonials */
.testimonials {
    padding: var(--spacing-xxl) 0;
    background: var(--cream);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.testimonial-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
}

.stars {
    color: var(--accent-gold);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.testimonial-card p {
    color: var(--gray-text);
    font-style: italic;
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

.testimonial-author strong {
    display: block;
    color: var(--dark-text);
    font-weight: 600;
}

.testimonial-author span {
    color: var(--gray-text);
    font-size: 0.875rem;
}

/* CTA Section */
.cta-section {
    padding: var(--spacing-xxl) 0;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--dark-blue) 100%);
    color: white;
    text-align: center;
}

.cta-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
}

.cta-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: var(--spacing-lg);
}

.cta-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-md);
}

.cta-section .btn-primary {
    background: white;
    color: var(--primary-blue);
}

.cta-section .btn-primary:hover {
    background: var(--off-white);
}

.cta-section .btn-secondary {
    border-color: white;
    color: white;
}

.cta-section .btn-secondary:hover {
    background: white;
    color: var(--primary-blue);
}

.cta-guarantee {
    opacity: 0.8;
    font-size: 0.875rem;
}

/* Footer */
.footer {
    padding: var(--spacing-xl) 0 var(--spacing-md);
    background: var(--dark-text);
    color: white;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-section h4 {
    margin-bottom: var(--spacing-sm);
    color: white;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: var(--spacing-xs);
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.footer-section p {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
}

/* Responsive Design */
@media (max-width: 768px) {
    .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-lg);
        padding: var(--spacing-md) 0;
    }

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

    .hamburger {
        display: flex;
    }

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

    .hero-image {
        order: -1;
        margin-bottom: var(--spacing-lg);
    }

    .book-cover {
        max-width: 300px;
    }

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

    .author-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .author-credentials {
        justify-content: center;
    }

    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 300px;
    }
}