:root {
    --color-primary: #0ea5e9;
    --color-secondary: #2dd4bf;
    --color-accent: #06b6d4;
    --color-dark: #0f172a;
    --color-darker: #020617;
    --color-gray: #1e293b;
    --color-light-gray: #475569;
    --color-text: #e2e8f0;
    --color-text-muted: #94a3b8;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    --max-width: 1200px;
    --transition: all 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--color-darker) 0%, var(--color-dark) 100%);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid rgba(14, 165, 233, 0.2);
}

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

.nav-brand a {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-decoration: none;
    color: var(--color-primary);
    text-shadow: 0 0 20px rgba(14, 165, 233, 0.5);
}

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

.nav-menu a {
    text-decoration: none;
    color: var(--color-text);
    transition: var(--transition);
    padding: 0.5rem 1rem;
}

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

.btn-signup {
    background: var(--color-primary);
    color: white;
    border-radius: 4px;
}

.btn-signup:hover {
    background: var(--color-accent);
    color: white;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--color-primary);
    transition: var(--transition);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding-top: 80px;
    background: 
        radial-gradient(ellipse at top, rgba(14, 165, 233, 0.15), transparent 50%),
        radial-gradient(ellipse at bottom, rgba(45, 212, 191, 0.1), transparent 50%);
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 1.2rem;
    text-transform: uppercase;
    letter-spacing: 4px;
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
}

.hero-subtitle {
    font-size: 5rem;
    font-weight: 900;
    letter-spacing: 8px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
    text-shadow: 0 0 40px rgba(14, 165, 233, 0.3);
}

.hero-tagline {
    font-size: 1.2rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
    letter-spacing: 2px;
}

.hero-description {
    font-size: 1.3rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
    line-height: 1.8;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
}

/* Buttons */
.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
}

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

.btn-primary:hover {
    background: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(14, 165, 233, 0.3);
}

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

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

.btn-text {
    background: none;
    color: var(--color-primary);
    padding: 0.5rem 0;
    font-weight: 600;
}

.btn-text:hover {
    color: var(--color-secondary);
}

/* Newsletter Section */
.newsletter {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.1), rgba(45, 212, 191, 0.05));
    border-top: 1px solid rgba(14, 165, 233, 0.2);
    border-bottom: 1px solid rgba(14, 165, 233, 0.2);
}

.newsletter-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.newsletter h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.newsletter p {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

.signup-form {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.signup-form input {
    flex: 1;
    padding: 1rem;
    border: 2px solid var(--color-gray);
    border-radius: 4px;
    background: var(--color-dark);
    color: var(--color-text);
    font-size: 1rem;
}

.signup-form input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.privacy-note {
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

/* Free Content Section */
.free-content {
    padding: var(--spacing-xl) 0;
}

.free-content h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary);
}

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

.content-card {
    background: var(--color-gray);
    padding: var(--spacing-md);
    border-radius: 8px;
    border: 1px solid rgba(14, 165, 233, 0.2);
    transition: var(--transition);
    text-align: center;
}

.content-card:hover {
    transform: translateY(-5px);
    border-color: var(--color-primary);
    box-shadow: 0 10px 40px rgba(14, 165, 233, 0.2);
}

.content-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

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

.content-card p {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

/* Series Section */
.series {
    padding: var(--spacing-xl) 0;
    background: rgba(15, 23, 42, 0.5);
}

.section-title {
    text-align: center;
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-lg);
}

.books-grid {
    display: grid;
    gap: var(--spacing-lg);
}

.book-card {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--spacing-md);
    background: var(--color-gray);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid rgba(14, 165, 233, 0.2);
    transition: var(--transition);
}

.book-card:hover {
    border-color: var(--color-primary);
    box-shadow: 0 10px 40px rgba(14, 165, 233, 0.2);
}

.book-cover {
    position: relative;
    overflow: hidden;
    background: var(--color-dark);
}

.book-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.book-card:hover .book-cover img {
    transform: scale(1.05);
}

.book-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition);
}

.book-card:hover .book-overlay {
    opacity: 1;
}

.book-info {
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.book-info h3 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}

.book-number {
    font-size: 1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.book-tagline {
    font-size: 1.3rem;
    font-style: italic;
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
}

.book-description {
    color: var(--color-text-muted);
    line-height: 1.8;
    margin-bottom: var(--spacing-sm);
}

.placeholder-cover {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-gray), var(--color-dark));
    font-size: 1.5rem;
    color: var(--color-text-muted);
    min-height: 450px;
}

.coming-soon {
    opacity: 0.9;
}

/* About Section */
.about {
    padding: var(--spacing-xl) 0;
}

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

.about-text h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

.about-text p {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-text-muted);
    line-height: 1.8;
}

.placeholder-image {
    aspect-ratio: 3/4;
    background: var(--color-gray);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    font-size: 1.2rem;
    border: 1px solid rgba(14, 165, 233, 0.2);
}

/* Footer */
.footer {
    background: var(--color-darker);
    padding: var(--spacing-lg) 0 var(--spacing-md);
    border-top: 1px solid rgba(14, 165, 233, 0.2);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.footer-brand h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    letter-spacing: 2px;
}

.footer-brand p {
    color: var(--color-text-muted);
}

.footer-links h4,
.footer-legal h4 {
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
}

.footer-links ul,
.footer-legal ul {
    list-style: none;
}

.footer-links a,
.footer-legal a {
    color: var(--color-text-muted);
    text-decoration: none;
    transition: var(--transition);
}

.footer-links a:hover,
.footer-legal a:hover {
    color: var(--color-primary);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(14, 165, 233, 0.1);
    color: var(--color-text-muted);
}

/* Responsive */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--color-dark);
        width: 100%;
        text-align: center;
        transition: var(--transition);
        padding: var(--spacing-md);
    }

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

    .hero-subtitle {
        font-size: 3rem;
    }

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

    .signup-form {
        flex-direction: column;
    }

    .book-card {
        grid-template-columns: 1fr;
    }

    .book-cover {
        min-height: 400px;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-subtitle {
        font-size: 2rem;
        letter-spacing: 4px;
    }

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

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