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

:root {
    --primary-color: #0066cc;
    --secondary-color: #1e40af;
    --accent-color: #00bcd4;
    --success-color: #10b981;
    --warning-color: #ff9800;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.2);
}

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

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

/* Navigation */
header {
    background-color: var(--bg-white);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    padding: 1rem 0;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-dark);
    transition: color 0.3s;
}

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

.cta-link {
    background-color: var(--primary-color);
    color: white !important;
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
}

/* Announcement Banner */
.announcement-banner {
    background: linear-gradient(135deg, #1e40af 0%, #7c3aed 100%);
    color: white;
    text-align: center;
    padding: 12px 20px;
    font-size: 15px;
    letter-spacing: 0.3px;
}

.banner-strikethrough {
    text-decoration: line-through;
    opacity: 0.7;
    margin: 0 4px;
}

.banner-bonus {
    color: #fde68a;
    font-weight: 600;
}

.banner-cta {
    display: inline-block;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    text-decoration: none;
    padding: 4px 16px;
    border-radius: 20px;
    margin-left: 12px;
    font-weight: 600;
    transition: background 0.3s;
}

.banner-cta:hover {
    background: rgba(255, 255, 255, 0.35);
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: var(--bg-gradient);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,%3Csvg width="60" height="60" viewBox="0 0 60 60" xmlns="http://www.w3.org/2000/svg"%3E%3Cg fill="none" fill-rule="evenodd"%3E%3Cg fill="%23ffffff" fill-opacity="0.05"%3E%3Cpath d="M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z"/%3E%3C/g%3E%3C/g%3E%3C/svg%3E');
    opacity: 0.3;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 2.75rem;
    margin-bottom: 0.5rem;
    line-height: 1.2;
    font-weight: 700;
}

.subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.95;
    font-weight: 600;
    color: var(--accent-color);
}

.description {
    font-size: 1.125rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.6;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}

.tech-badges {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.badge {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 600;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn {
    padding: 0.75rem 2rem;
    border-radius: 0.375rem;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    display: inline-block;
    border: none;
    cursor: pointer;
    text-align: center;
}

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

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

.btn-secondary {
    background-color: transparent;
    color: white;
    border: 2px solid white;
}

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

.btn-code {
    background-color: #24292e;
    color: white;
    border: 2px solid #fff;
}

.btn-code:hover {
    background-color: #2ea44f;
    transform: translateY(-2px);
}

.btn-contact {
    background-color: var(--primary-color);
    color: white;
    width: 100%;
    margin-top: 1rem;
}

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

.hero-image img {
    max-width: 100%;
    height: auto;
    border-radius: 0.5rem;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* About Section */
.about {
    padding: 4rem 0;
    background-color: var(--bg-white);
}

.about h2 {
    text-align: center;
    font-size: 2.25rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.about .intro {
    text-align: center;
    max-width: 900px;
    margin: 0 auto 3rem;
    font-size: 1.25rem;
    color: var(--text-light);
    line-height: 1.8;
}

.framework-highlight {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
    margin: 3rem 0;
    padding: 2rem;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    border-radius: 1rem;
}

.framework-text h3 {
    color: var(--primary-color);
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.framework-text ul {
    list-style: none;
    padding: 0;
    margin: 1.5rem 0;
}

.framework-text li {
    padding: 0.75rem 0;
    font-size: 1.05rem;
    line-height: 1.6;
}

.framework-result {
    font-size: 1.25rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-top: 1.5rem;
    padding: 1rem;
    background: white;
    border-radius: 0.5rem;
    text-align: center;
}

.framework-image img {
    max-width: 100%;
    height: auto;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-lg);
}

.stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    text-align: center;
    margin-top: 3rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    background: white;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
}

.stat-number {
    font-size: 3rem;
    font-weight: bold;
    color: var(--primary-color);
    line-height: 1;
}

.stat-label {
    font-size: 0.95rem;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.5rem;
}

/* Volumes Section */
.volumes {
    padding: 4rem 0;
    background-color: var(--bg-light);
}

.volumes h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--text-dark);
}

.volumes-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

.volume-card {
    background: white;
    border-radius: 0.75rem;
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

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

.volume-card.complete {
    grid-column: span 3;
    background: linear-gradient(135deg, #fff9f0 0%, #ffe5cc 100%);
    border: 2px solid var(--warning-color);
    position: relative;
}

.badge-best {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--warning-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-weight: 700;
    font-size: 0.85rem;
    text-transform: uppercase;
}

.volume-cover {
    width: 120px;
    height: auto;
    margin-bottom: 1rem;
    flex-shrink: 0;
}

.volume-card.complete .volume-cover {
    width: 180px;
}

.volume-cover img {
    width: 100%;
    height: auto;
    border-radius: 0.5rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.volume-cover.placeholder {
    width: 120px;
    height: 160px;
    background: linear-gradient(135deg, #e2e8f0 0%, #cbd5e1 100%);
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.volume-cover.placeholder span {
    font-size: 3rem;
    font-weight: bold;
    color: #94a3b8;
}

.volume-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
}

.volume-info h3 {
    font-size: 1.1rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.vol-title {
    font-size: 0.95rem;
    color: var(--text-dark);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.volume-info .chapters {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 0.75rem;
}

.status-badge {
    display: inline-block;
    padding: 0.35rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 1rem;
}

.status-badge.available {
    background-color: #10b981;
    color: white;
}

.status-badge.coming-soon {
    background-color: #64748b;
    color: white;
}

.price-options {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    width: 100%;
    margin-top: auto;
}

.btn-buy {
    padding: 0.6rem 1rem;
    font-size: 0.85rem;
    border: none;
    border-radius: 0.375rem;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
    background-color: var(--primary-color);
    color: white;
}

.btn-buy:hover {
    background-color: var(--secondary-color);
    transform: scale(1.02);
}

.btn-buy.btn-featured {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
}

.btn-buy.btn-featured:hover {
    background: linear-gradient(135deg, #059669 0%, #047857 100%);
}

.volume-card.complete .price {
    margin: 1rem 0;
}

.volume-card.complete .new-price {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

/* Responsive Volumes Grid */
@media (max-width: 1024px) {
    .volumes-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .volume-card.complete {
        grid-column: span 2;
    }
}

@media (max-width: 640px) {
    .volumes-grid {
        grid-template-columns: 1fr;
    }

    .volume-card.complete {
        grid-column: span 1;
    }

    .volume-cover {
        width: 100px;
    }

    .volume-card.complete .volume-cover {
        width: 140px;
    }
}

/* Features Section */
.features {
    padding: 4rem 0;
    background-color: var(--bg-light);
}

.features h2 {
    text-align: center;
    font-size: 2.25rem;
    margin-bottom: 3rem;
    color: var(--text-dark);
}

.parts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.part-card {
    background-color: var(--bg-white);
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s;
    border-left: 4px solid var(--primary-color);
    position: relative;
}

.part-card.highlighted {
    background: linear-gradient(135deg, #fff5e1 0%, #ffe5b4 100%);
    border-left-color: var(--warning-color);
}

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

.part-number {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 0.75rem;
}

.part-card.highlighted .part-number {
    background: var(--warning-color);
}

.part-card h3 {
    color: var(--text-dark);
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.part-card p {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.chapters {
    display: inline-block;
    font-size: 0.875rem;
    color: var(--primary-color);
    font-weight: 600;
    background: rgba(0, 102, 204, 0.1);
    padding: 0.25rem 0.75rem;
    border-radius: 0.25rem;
}

.tech-highlight {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--warning-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.75rem;
    font-weight: 700;
    box-shadow: var(--shadow-sm);
}

.code-showcase {
    background: white;
    padding: 3rem;
    border-radius: 1rem;
    margin-top: 3rem;
    box-shadow: var(--shadow-md);
}

.code-showcase h3 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-dark);
}

.code-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.code-feature {
    text-align: center;
}

.code-feature .icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 1rem;
}

.code-feature h4 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
}

.code-feature p {
    color: var(--text-light);
    line-height: 1.6;
}

/* Author Section */
.author {
    padding: 4rem 0;
    background-color: var(--bg-white);
}

.author h2 {
    text-align: center;
    font-size: 2.25rem;
    margin-bottom: 3rem;
}

.author-bio {
    display: flex;
    gap: 3rem;
    align-items: flex-start;
    max-width: 900px;
    margin: 0 auto;
}

.author-image {
    flex-shrink: 0;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: var(--shadow-lg);
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    pointer-events: none;
}

.author-placeholder {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: var(--bg-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 4rem;
    font-weight: bold;
    color: white;
    box-shadow: var(--shadow-lg);
}

.bio-text h3 {
    margin-bottom: 0.5rem;
    color: var(--primary-color);
    font-size: 1.75rem;
}

.bio-text .title {
    color: var(--text-light);
    font-size: 1.125rem;
    margin-bottom: 1.5rem;
    font-style: italic;
}

.bio-text p {
    margin-bottom: 1rem;
    line-height: 1.8;
    color: var(--text-dark);
}

/* Buy Section */
.buy {
    padding: 4rem 0;
    background-color: var(--bg-light);
}

.buy h2 {
    text-align: center;
    font-size: 2.25rem;
    margin-bottom: 1rem;
}

.buy-subtitle {
    text-align: center;
    font-size: 1.125rem;
    color: var(--text-light);
    margin-bottom: 3rem;
}

/* Complete Book Banner */
.complete-book-banner {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 1rem;
    padding: 3rem;
    margin-bottom: 4rem;
    color: white;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.banner-content h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: white;
}

.banner-tag {
    display: inline-block;
    background: var(--warning-color);
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: 2rem;
    font-weight: 700;
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

.banner-price {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
    flex-wrap: wrap;
}

.old-price {
    font-size: 1.5rem;
    text-decoration: line-through;
    opacity: 0.7;
}

.new-price {
    font-size: 3.5rem;
    font-weight: bold;
}

.savings {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 600;
}

/* Section Titles */
.section-title {
    text-align: center;
    font-size: 1.75rem;
    margin: 3rem 0 0.5rem;
    color: var(--text-dark);
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 2rem;
}

/* Pricing Grid */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.price-card.compact {
    background-color: var(--bg-white);
    padding: 1.5rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-sm);
    border: 2px solid transparent;
    transition: all 0.3s;
    position: relative;
}

.price-card.compact.highlighted {
    border-color: var(--warning-color);
    background: linear-gradient(135deg, #fff9f0 0%, #ffe5cc 100%);
}

.price-card.compact:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.part-label {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}

.price-card.compact h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.chapters-info {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

.hot-badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--warning-color);
    color: white;
    padding: 0.35rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.7rem;
    font-weight: 700;
}

/* Part Pricing Options */
.part-pricing {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.format-option {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem;
    background: var(--bg-light);
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

.format-option.featured-format {
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    border-color: var(--primary-color);
}

.format-option .format {
    font-weight: 600;
    color: var(--text-dark);
    font-size: 0.9rem;
}

.format-option .amount {
    font-weight: 700;
    color: var(--primary-color);
    font-size: 1.1rem;
}

.buy-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1.25rem;
    border-radius: 0.375rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 0.875rem;
}

.buy-btn:hover {
    background: var(--secondary-color);
    transform: translateX(3px);
}

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

.buy-btn.primary:hover {
    background: #059669;
}

/* Purchase Modal */
.purchase-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    padding: 1rem;
}

.modal-content {
    background: white;
    padding: 2.5rem;
    border-radius: 1rem;
    max-width: 500px;
    width: 100%;
    position: relative;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.modal-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-light);
    line-height: 1;
}

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

.modal-content h2 {
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.purchase-details {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: 0.5rem;
    margin-bottom: 1.5rem;
}

.book-details {
    line-height: 1.8;
    margin: 0;
}

.purchase-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

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

.form-group label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.form-group input {
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 0.375rem;
    font-size: 1rem;
    transition: border-color 0.3s;
}

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

.form-group small {
    margin-top: 0.25rem;
    color: var(--text-light);
    font-size: 0.875rem;
}

.form-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.btn-cancel {
    flex: 1;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    background: white;
    border-radius: 0.375rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-cancel:hover {
    background: var(--bg-light);
}

.btn-continue {
    flex: 2;
    padding: 0.75rem;
    border: none;
    background: var(--primary-color);
    color: white;
    border-radius: 0.375rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

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

/* Guarantee Section */
.guarantee {
    background: white;
    padding: 2rem;
    border-radius: 0.75rem;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
    box-shadow: var(--shadow-sm);
}

.guarantee h3 {
    color: var(--success-color);
    margin-bottom: 0.5rem;
}

.guarantee p {
    margin: 0.5rem 0;
}

.guarantee small {
    color: var(--text-light);
}

/* Footer */
footer {
    background-color: var(--text-dark);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

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

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s;
}

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

/* Responsive Design */
@media (max-width: 968px) {
    .hero .container,
    .framework-highlight {
        grid-template-columns: 1fr;
    }
    
    .hero h1 {
        font-size: 2.25rem;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .hero-cta .btn {
        width: 100%;
    }
    
    .stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .parts-grid,
    .pricing-grid {
        grid-template-columns: 1fr;
    }
    
    .author-bio {
        flex-direction: column;
        text-align: center;
    }
    
    .nav-links {
        flex-direction: column;
        gap: 1rem;
    }
    
    footer .container {
        flex-direction: column;
        gap: 1rem;
    }
    
    .complete-book-banner {
        padding: 2rem 1.5rem;
    }
    
    .banner-price {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .new-price {
        font-size: 2.5rem;
    }
}

@media (max-width: 640px) {
    .stats {
        grid-template-columns: 1fr;
    }
    
    .hero h1 {
        font-size: 1.75rem;
    }
    
    .subtitle {
        font-size: 1.25rem;
    }
    
    .modal-content {
        padding: 1.5rem;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .format-option {
        flex-direction: column;
        gap: 0.5rem;
        text-align: center;
    }
}

/* Status Badges */
.status-badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-top: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.status-badge.available {
    background-color: #10b981;
    color: white;
}

.status-badge.coming-soon {
    background-color: #6b7280;
    color: white;
}

/* Platform Integration Section */
.platform-integration {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.platform-integration h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.platform-callout {
    max-width: 800px;
    margin: 0 auto;
}

.platform-link a {
    color: white;
    text-decoration: none;
    border-bottom: 2px solid white;
    transition: all 0.3s ease;
}

.platform-link a:hover {
    opacity: 0.8;
    border-bottom-color: rgba(255, 255, 255, 0.5);
}

/* Use Cases Section */
.use-cases {
    padding: 4rem 0;
    background-color: var(--bg-white);
}

.use-cases h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--text-dark);
}

.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.use-case {
    text-align: center;
    padding: 2rem;
    background: var(--bg-light);
    border-radius: 12px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.use-case:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.use-case .icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 1rem;
}

.use-case p {
    font-size: 1rem;
    color: var(--text-dark);
    line-height: 1.6;
}

/* ==================================
   SHOPPING CART STYLES
   ================================== */

/* Cart Button in Navigation */
.cart-btn {
    position: relative;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    color: var(--text-dark);
    transition: color 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.cart-btn:hover {
    color: var(--primary-color);
}

.cart-badge {
    position: absolute;
    top: 0;
    right: 0;
    background-color: #ef4444;
    color: white;
    font-size: 0.75rem;
    font-weight: bold;
    border-radius: 50%;
    width: 20px;
    height: 20px;
    display: none;
    align-items: center;
    justify-content: center;
}

/* Cart Overlay */
.cart-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 9998;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}

.cart-overlay.active {
    opacity: 1;
    visibility: visible;
}

/* Cart Panel */
.cart-panel {
    position: fixed;
    top: 0;
    right: -400px;
    width: 400px;
    max-width: 100%;
    height: 100vh;
    background-color: white;
    box-shadow: -2px 0 20px rgba(0, 0, 0, 0.1);
    z-index: 9999;
    display: flex;
    flex-direction: column;
    transition: right 0.3s ease-in-out;
}

.cart-panel.open {
    right: 0;
}

/* Cart Header */
.cart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.cart-header h2 {
    font-size: 1.5rem;
    color: var(--text-dark);
}

.close-cart {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    color: var(--text-dark);
    transition: color 0.3s;
}

.close-cart:hover {
    color: var(--primary-color);
}

/* Cart Body */
.cart-body {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
}

.empty-cart {
    text-align: center;
    color: var(--text-light);
    padding: 2rem;
}

/* Cart Item */
.cart-item {
    display: flex;
    gap: 1rem;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.2s;
}

.cart-item:hover {
    background-color: var(--bg-light);
}

.cart-item-info {
    flex: 1;
}

.cart-item-info h4 {
    font-size: 0.9rem;
    color: var(--text-dark);
    margin-bottom: 0.25rem;
}

.cart-item-format {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-bottom: 0.25rem;
}

.cart-item-chapters {
    font-size: 0.75rem;
    color: var(--text-light);
}

.cart-item-price {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.5rem;
}

.cart-item-price .price {
    font-weight: bold;
    color: var(--primary-color);
    font-size: 1rem;
}

.remove-btn {
    background: none;
    border: none;
    cursor: pointer;  
    color: #ef4444;
    padding: 0.25rem;
    transition: opacity 0.2s;
}

.remove-btn:hover {
    opacity: 0.7;
}

/* Cart Footer */
.cart-footer {
    padding: 1.5rem;
    border-top: 2px solid var(--border-color);
    background-color: var(--bg-light);
}

.cart-total-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    font-size: 1.25rem;
    font-weight: bold;
}

.cart-total {
    color: var(--primary-color);
}

.checkout-btn {
    width: 100%;
    margin-bottom: 0.5rem;
}

.checkout-btn:disabled {
    background-color: var(--text-light);
    cursor: not-allowed;
    opacity: 0.5;
}

.btn-secondary {
    width: 100%;
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

/* Cart Notifications */
.cart-notification {
    position: fixed;
    top: 80px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-lg);
    z-index: 10000;
    transform: translateX(400px);
    transition: transform 0.3s ease;
    font-weight: 500;
}

.cart-notification.show {
    transform: translateX(0);
}

.cart-notification.success {
    background-color: #10b981;
    color: white;
}

.cart-notification.error {
    background-color: #ef4444;
    color: white;
}

.cart-notification.info {
    background-color: #3b82f6;
    color: white;
}

/* Checkout Modal */
.checkout-items-list {
    list-style: none;
    padding: 0;
    margin: 1rem 0;
}

.checkout-items-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.checkout-total {
    display: flex;
    justify-content: space-between;
    font-size: 1.25rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 2px solid var(--border-color);
}

.total-amount {
    color: var(--primary-color);
    font-weight: bold;
}

/* Responsive Cart */
@media (max-width: 768px) {
    .cart-panel {
        width: 100%;
        right: -100%;
    }

    .cart-notification {
        right: 10px;
        left: 10px;
        transform: translateY(-100px);
    }

    .cart-notification.show {
        transform: translateY(0);
    }

    nav .container {
        gap: 1rem;
    }

    .nav-links {
        gap: 1rem;
        font-size: 0.9rem;
    }
}