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

:root {
    --earth-brown: #8B6F47;
    --earth-tan: #D4B896;
    --earth-light: #ECE6DB; 
    --earth-dark: #4A3728;
    --accent-green: #6B8E23;
    --accent-orange: #D97330;
    --text-primary: #2C2416;
    --text-secondary: #6B5D4F;
    --white: #FFFFFF;
    --gray-light: #F8F6F3;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--white);
}

/* TIER 1: HERO SPOTLIGHT */
.hero {
    position: relative;
    height: 400px;
    background: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.4)),
                url('/placeholder.svg?height=400&width=1600') center/cover;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    text-shadow: 2px 2px 8px rgba(0,0,0,0.5);
    max-width: 900px;
    padding: 0 20px;
}

.hero-divider {
    height: 6px;
    background: linear-gradient(90deg, var(--earth-brown) 0%, var(--earth-tan) 50%, var(--earth-brown) 100%);
}

/* TIER 2: FEATURED PUBLICATION */
.featured-section {
    background-color: var(--earth-light);
    padding: 80px 20px;
}

.featured-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 40% 60%;
    gap: 60px;
    align-items: start;
}

.featured-image {
    position: relative;
}

.featured-image img {
    width: 100%;
    height: auto;
    box-shadow: 0 20px 60px rgba(0,0,0,0.2);
    border-radius: 8px;
}

.exclusive-badge {
    position: absolute;
    top: -15px;
    right: -15px;
    background: var(--accent-orange);
    color: var(--white);
    padding: 10px 20px;
    border-radius: 30px;
    font-weight: 700;
    font-size: 0.85rem;
    text-transform: uppercase;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.featured-content h2 {
    font-size: 2.5rem;
    color: var(--earth-dark);
    margin-bottom: 15px;
    line-height: 1.2;
}

.featured-tagline {
    font-size: 1.2rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-bottom: 25px;
}

.featured-description {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--text-primary);
    margin-bottom: 40px;
}

.pricing-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 30px;
    background: var(--white);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.pricing-table th,
.pricing-table td {
    padding: 18px;
    text-align: center;
    border: 1px solid #E5DDD0;
    width: 33%;
}

.pricing-table th {
    background-color: var(--earth-brown);
    color: var(--white);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.9rem;
}

.pricing-table td:first-child {
    text-align: left;
    font-weight: 600;
    color: var(--earth-dark);
}

.pricing-table td {
    font-size: 1.1rem;
    color: var(--text-primary);
}

.buy-button {
    position: relative;
    display: block;
    width: 100%;
    max-width: 400px;
    box-sizing: border-box;
    background-color: white;
    color: var(--earth-dark);
    border: none;
    border-radius: 30px;
    padding: 18px 60px 18px 30px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    text-decoration: none;
    text-align: center;
}

.buy-button:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transform: none; /* Removed previous hover effect */
    background: white; /* Override previous hover effect */
}

.arrow-circle {
    position: absolute;
    right: 5px;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    background-color: #22c55e; /* green-500 */
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.arrow-circle svg {
    width: 20px;
    height: 20px;
    fill: white;
}

/* TIER 3: RESOURCE LIBRARY */
.library-section {
    padding: 80px 20px;
    background: var(--white);
}

.library-container {
    max-width: 1400px;
    margin: 0 auto;
}

.library-divider {
    text-align: center;
    margin-bottom: 40px;
}

.library-divider svg {
    width: 60px;
    height: 60px;
    fill: var(--earth-brown);
}

.library-intro {
    max-width: 900px;
    margin: 0 auto 50px;
    text-align: center;
}

.library-intro h2 {
    font-size: 2.5rem;
    color: var(--earth-dark);
    margin-bottom: 20px;
}

.library-intro p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

/* FILTER BAR */
.filter-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
    margin-bottom: 50px;
}

.filter-btn {
    padding: 12px 24px;
    background: var(--gray-light);
    border: 2px solid transparent;
    border-radius: 30px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.filter-btn:hover {
    background: var(--earth-light);
    color: var(--earth-dark);
}

.filter-btn.active {
    background: var(--earth-brown);
    color: var(--white);
    border-color: var(--earth-dark);
}

/* PUBLICATIONS GRID */
.publications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
}

.publication-card {
    background: var(--white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

.publication-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card-cover {
    position: relative;
    height: 350px;
    background: var(--gray-light);
    overflow: hidden;
}

.card-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.card-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(139, 111, 71, 0.9), rgba(74, 55, 40, 0.85));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    color: var(--white);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.card-overlay.vintage {
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.3));
}

.pdf-badge,
.vintage-badge {
    position: absolute;
    top: 15px;
    right: 15px;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    z-index: 1;
}

.pdf-badge {
    background: var(--accent-green);
    color: var(--white);
}

.vintage-badge {
    background: var(--text-secondary);
    color: var(--white);
}

.card-content {
    padding: 20px;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.category-tag {
    display: inline-block;
    padding: 5px 12px;
    background: var(--earth-light);
    color: var(--earth-brown);
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 12px;
    text-transform: uppercase;
}

.card-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--earth-dark);
    margin-bottom: 8px;
    line-height: 1.3;
}

.card-author {
    font-style: italic;
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 5px;
}

.card-year {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 10px;
}

.card-isbn {
    font-family: 'Courier New', monospace;
    font-size: 0.85rem;
    color: var(--earth-brown);
    margin-top: auto;
    padding-top: 10px;
    border-top: 1px solid var(--earth-light);
    cursor: pointer;
    transition: color 0.2s ease;
}

.card-isbn:hover {
    color: var(--accent-green);
}

.card-links {
    margin-top: 15px;
    padding-top: 10px;
    display: flex;
    gap: 1rem;
}

.card-link {
    color: #1175b5;
    text-decoration: underline;
    font-weight: 600;
    font-size: 0.9rem;
}

.card-link:hover {
    color: var(--earth-dark);
}

/* RESPONSIVE DESIGN */
@media (max-width: 1024px) {
    .featured-container {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .featured-image {
        max-width: 400px;
        margin: 0 auto;
    }

    .publications-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }

    .featured-content h2 {
        font-size: 1.8rem;
    }

    .library-intro h2 {
        font-size: 2rem;
    }

    .publications-grid {
        grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
        gap: 20px;
    }

    .filter-bar {
        gap: 8px;
    }

    .filter-btn {
        padding: 10px 18px;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .hero {
        height: 300px;
    }

    .hero h1 {
        font-size: 1.5rem;
    }

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

    .filter-btn {
        flex: 1 1 calc(50% - 8px);
        min-width: 140px;
    }
}