/* ===========================
   CSS Reset & Base Styles
   =========================== */

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

:root {
    /* Color Palette */
    --color-bg-primary: #0a0a0a;
    --color-bg-secondary: #1a1a1a;
    --color-bg-tertiary: #2a2a2a;
    --color-text-primary: #ffffff;
    --color-text-secondary: #b0b0b0;
    --color-accent: #6366f1;
    --color-accent-hover: #4f46e5;
    --color-accent-glow: rgba(99, 102, 241, 0.3);

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
    color: var(--color-text-primary);
    line-height: 1.6;
    font-size: 16px;
    min-height: 100vh;
}

/* ===========================
   Typography
   =========================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: clamp(2.5rem, 5vw, 4rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }
h4 { font-size: 1.25rem; }

p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

/* ===========================
   Layout Containers
   =========================== */

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

section {
    padding: var(--spacing-xl) 0;
    position: relative;
}

/* ===========================
   Header & Navigation
   =========================== */

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 10, 10, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-sm) var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text-primary);
    letter-spacing: 0.1em;
}

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

.nav-link {
    color: var(--color-text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background: var(--color-text-primary);
    transition: var(--transition-normal);
}

/* ===========================
   Buttons
   =========================== */

.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-normal);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: var(--color-accent);
    color: var(--color-text-primary);
    box-shadow: 0 4px 15px var(--color-accent-glow);
}

.btn-primary:hover {
    background: var(--color-accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--color-accent-glow);
}

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

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

/* ===========================
   Hero Section
   =========================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: var(--spacing-xl);
    background:
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 50%, rgba(99, 102, 241, 0.05) 0%, transparent 50%);
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.hero-title {
    background: linear-gradient(135deg, var(--color-text-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-accent);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

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

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

.book-cover {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    box-shadow:
        0 20px 60px rgba(0, 0, 0, 0.5),
        0 0 40px var(--color-accent-glow);
    transition: transform var(--transition-slow);
}

.book-cover:hover {
    transform: scale(1.05) rotateY(5deg);
}

/* ===========================
   Section Headers
   =========================== */

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.section-title {
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    color: var(--color-text-secondary);
    font-size: 1.125rem;
}

/* ===========================
   Book Section
   =========================== */

.book-section {
    background: var(--color-bg-secondary);
}

.genre-tags {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-sm);
}

.tag {
    padding: 0.5rem 1rem;
    background: var(--color-bg-tertiary);
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--color-accent);
    border: 1px solid var(--color-accent);
}

.book-content {
    max-width: 800px;
    margin: 0 auto;
}

.book-description p {
    font-size: 1.125rem;
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.book-hook {
    font-weight: 600;
    color: var(--color-text-primary);
    font-style: italic;
}

.book-tagline {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-accent);
    text-align: center;
    margin-top: var(--spacing-lg);
}

/* ===========================
   Buy Links Section
   =========================== */

.buy-section {
    background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
}

.buy-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    max-width: 900px;
    margin: 0 auto var(--spacing-md);
}

.buy-button {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: var(--color-bg-tertiary);
    border: 2px solid transparent;
    border-radius: 12px;
    transition: all var(--transition-normal);
    color: var(--color-text-primary);
}

.buy-button:hover {
    border-color: var(--color-accent);
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.buy-icon {
    font-size: 2.5rem;
}

.buy-text {
    font-weight: 600;
    font-size: 1.125rem;
}

.buy-note {
    text-align: center;
    color: var(--color-text-secondary);
    font-style: italic;
}

/* ===========================
   Author Section
   =========================== */

.author-section {
    background: var(--color-bg-secondary);
}

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

.author-bio p {
    font-size: 1.125rem;
    line-height: 1.8;
}

/* ===========================
   Newsletter Section
   =========================== */

.newsletter-section {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-hover) 100%);
    color: var(--color-text-primary);
}

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

.newsletter-title {
    margin-bottom: var(--spacing-sm);
}

.newsletter-description {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
    color: rgba(255, 255, 255, 0.9);
}

.newsletter-form {
    margin-top: var(--spacing-md);
}

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

.form-input {
    flex: 1;
    padding: 1rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    background: rgba(255, 255, 255, 0.95);
    color: var(--color-bg-primary);
}

.form-input:focus {
    outline: 3px solid rgba(255, 255, 255, 0.5);
}

.form-note {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.8);
    margin-top: var(--spacing-xs);
}

.form-message {
    margin-top: var(--spacing-sm);
    padding: var(--spacing-sm);
    border-radius: 8px;
    display: none;
}

.form-message.success {
    display: block;
    background: rgba(34, 197, 94, 0.2);
    border: 1px solid rgba(34, 197, 94, 0.5);
}

.form-message.error {
    display: block;
    background: rgba(239, 68, 68, 0.2);
    border: 1px solid rgba(239, 68, 68, 0.5);
}

.integration-note {
    margin-top: var(--spacing-md);
    font-size: 0.75rem;
    opacity: 0;
}

/* ===========================
   Footer
   =========================== */

.footer {
    background: var(--color-bg-primary);
    padding: var(--spacing-lg) 0 var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-title {
    color: var(--color-accent);
    margin-bottom: var(--spacing-sm);
}

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

.footer-heading {
    margin-bottom: var(--spacing-sm);
    font-size: 1rem;
}

.social-links {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.social-link {
    color: var(--color-text-secondary);
    transition: color var(--transition-fast);
}

.social-link:hover {
    color: var(--color-accent);
}

.footer-links {
    list-style: none;
}

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

.footer-links a {
    color: var(--color-text-secondary);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--color-text-secondary);
    font-size: 0.875rem;
}

/* ===========================
   Animations
   =========================== */

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===========================
   Responsive Design
   =========================== */

@media (max-width: 968px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

    .book-cover {
        max-width: 400px;
    }
}

@media (max-width: 768px) {
    :root {
        --spacing-xl: 4rem;
        --spacing-lg: 3rem;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: rgba(10, 10, 10, 0.98);
        flex-direction: column;
        padding: var(--spacing-md);
        transform: translateX(-100%);
        transition: transform var(--transition-normal);
    }

    .nav-menu.active {
        transform: translateX(0);
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }

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

    .buy-links {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-cta {
        flex-direction: column;
        width: 100%;
    }

    .btn {
        width: 100%;
    }

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