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

:root {
    --primary-color: #E8D5B7;
    --secondary-color: #2C2C2C;
    --accent-color: #1a1a1a;
    --text-color: #333;
    --light-bg: #f5f5f5;
    --white: #ffffff;
    --border-color: #e0e0e0;
    --sidebar-width: 32px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--light-bg);
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--light-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: #d4c4a3;
}

* {
    scrollbar-width: thin;
    scrollbar-color: var(--primary-color) var(--light-bg);
}

/* Advertorial Notice */
.advertorial-notice {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: #ff6b6b;
    color: var(--white);
    text-align: center;
    padding: 12px;
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 2px;
    z-index: 999;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

/* Sidebar */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background-color: var(--primary-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 60px 0 20px;
    gap: 20px;
    z-index: 1000;
}

.sidebar button {
    background: none;
    border: none;
    font-size: 18px;
    cursor: pointer;
    color: var(--secondary-color);
    padding: 8px;
    transition: transform 0.3s ease;
}

.sidebar button:hover {
    transform: scale(1.1);
}

/* Main Content */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 40px 40px;
}

/* Hero Section */
.hero {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    margin-bottom: 100px;
    padding: 40px 0;
}

.site-title {
    font-size: 48px;
    font-weight: 300;
    color: var(--secondary-color);
    margin-bottom: 10px;
    line-height: 1.2;
}

.subtitle {
    display: block;
    font-size: 14px;
    font-weight: 400;
    color: #666;
    margin-top: 10px;
    letter-spacing: 2px;
}

.hero-text {
    margin-top: 30px;
}

.hero-text p {
    font-size: 16px;
    line-height: 1.8;
    color: #555;
    margin-bottom: 30px;
}

.cta-buttons {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 30px;
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    border-radius: 4px;
    transition: all 0.3s ease;
    display: inline-block;
    text-align: center;
    letter-spacing: 0.5px;
}

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

.btn-primary:hover {
    background-color: transparent;
    color: var(--accent-color);
}

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

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

.btn-small {
    padding: 8px 20px;
    font-size: 12px;
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
    perspective: 1000px;
}

.hero-image img {
    max-width: 100%;
    height: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
    border-radius: 8px;
    transform: rotateY(-5deg) rotateX(2deg);
    transition: transform 0.5s ease;
}

.hero-image img:hover {
    transform: rotateY(0deg) rotateX(0deg) scale(1.02);
}

/* About Book Section */
.about-book {
    margin-bottom: 100px;
}

.about-book h2 {
    font-size: 36px;
    font-weight: 300;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.intro-text {
    font-size: 16px;
    line-height: 1.8;
    color: #555;
    margin-bottom: 50px;
    max-width: 800px;
}

/* Feature Grid */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
}

.feature-image {
    width: 100%;
    height: 250px;
    overflow: hidden;
}

.feature-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.feature-card:hover .feature-image img {
    transform: scale(1.1);
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin: 20px 20px 10px;
    color: var(--secondary-color);
}

.feature-card p {
    font-size: 14px;
    line-height: 1.6;
    color: #666;
    margin: 0 20px 20px;
}

.read-more {
    display: inline-block;
    margin: 0 20px 20px;
    color: var(--accent-color);
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    transition: color 0.3s ease;
}

.read-more:hover {
    color: #555;
}

/* Author Section */
.author-section {
    margin-bottom: 100px;
    background: var(--white);
    padding: 60px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.author-section h2 {
    font-size: 36px;
    font-weight: 300;
    margin-bottom: 40px;
    color: var(--secondary-color);
}

.author-content {
    display: grid;
    grid-template-columns: 400px 1fr;
    gap: 60px;
    align-items: start;
}

.author-image {
    width: 100%;
    height: 500px;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

.author-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: grayscale(20%);
}

.author-info h3 {
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 2px;
    color: var(--secondary-color);
    margin-bottom: 20px;
}

.author-info p {
    font-size: 16px;
    line-height: 1.8;
    color: #555;
    margin-bottom: 30px;
}

.author-info h4 {
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 2px;
    color: var(--secondary-color);
    margin: 40px 0 20px;
}

.other-books {
    display: flex;
    gap: 20px;
}

.book-item {
    text-align: center;
}

.book-item img {
    width: 150px;
    height: auto;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    border-radius: 4px;
    margin-bottom: 10px;
}

.book-item p {
    font-size: 12px;
    color: #666;
    margin-bottom: 10px;
}

/* Testimonials */
.testimonials {
    margin-bottom: 100px;
}

.testimonials h2 {
    font-size: 36px;
    font-weight: 300;
    margin-bottom: 40px;
    color: var(--secondary-color);
}

.testimonial-card {
    background: var(--white);
    padding: 50px;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    max-width: 900px;
    position: relative;
}

.quote-icon {
    font-size: 80px;
    color: var(--primary-color);
    line-height: 1;
    margin-bottom: 20px;
}

.testimonial-text {
    font-size: 18px;
    line-height: 1.8;
    color: #555;
    font-style: italic;
    margin-bottom: 20px;
}

.testimonial-author {
    font-size: 14px;
    color: #999;
    text-align: right;
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, var(--primary-color) 0%, #d4c4a3 100%);
    padding: 80px 60px;
    border-radius: 12px;
    text-align: center;
    margin-bottom: 100px;
}

.cta-section h2 {
    font-size: 42px;
    font-weight: 300;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.cta-section p {
    font-size: 18px;
    line-height: 1.8;
    color: #555;
    margin-bottom: 40px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.cta-section .cta-buttons {
    justify-content: center;
}

/* Footer */
.footer {
    background-color: var(--secondary-color);
    color: var(--white);
    padding: 60px 40px 30px;
    width: 100%;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-links,
.footer-research {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
}

.footer-links > *,
.footer-research > * {
    width: 100%;
    max-width: fit-content;
}

.footer h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.footer ul {
    list-style: none;
    text-align: left;
}

.footer ul li {
    margin-bottom: 10px;
}

.footer a {
    color: #ccc;
    text-decoration: none;
    font-size: 14px;
    transition: color 0.3s ease;
}

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

.footer-disclosures {
    max-width: 1000px;
    margin: 0 auto 40px;
    text-align: center;
}

.footer-disclosures h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 30px;
    color: var(--primary-color);
}

.disclosure {
    margin-bottom: 30px;
    text-align: center;
    display: inline-block;
    width: 100%;
}

.disclosure h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.disclosure p {
    font-size: 12px;
    line-height: 1.6;
    color: #aaa;
}

.footer-bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding-top: 30px;
    border-top: 1px solid #444;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.copyright {
    font-size: 12px;
    color: #888;
    text-align: center;
    margin: 0 auto;
}

/* Scroll to Top Button */
.scroll-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--accent-color);
    color: var(--white);
    border: none;
    border-radius: 50%;
    font-size: 24px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 999;
}

.scroll-top.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-top:hover {
    background-color: var(--primary-color);
    color: var(--secondary-color);
    transform: translateY(-5px);
}

/* Responsive Design */
@media (max-width: 968px) {
    .hero {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .author-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .author-image {
        height: 400px;
    }

    .site-title {
        font-size: 36px;
    }

    .main-content {
        padding: 80px 20px 40px;
    }

    .cta-section {
        padding: 60px 30px;
    }

    .author-section {
        padding: 40px 30px;
    }
}

@media (max-width: 640px) {
    .site-title {
        font-size: 28px;
    }

    .about-book h2,
    .author-section h2,
    .testimonials h2,
    .cta-section h2 {
        font-size: 28px;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

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

    .btn {
        width: 100%;
    }

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

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .advertorial-notice {
        font-size: 12px;
        padding: 10px;
    }
}