.white-papers-hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
    padding: 6rem 0;
    margin-bottom: 3rem;
}

.white-papers-hero h1 {
    color: white;
    margin-bottom: 1rem;
    font-size: 3rem;
}

.white-papers-hero p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.3rem;
    max-width: 600px;
    margin: 0 auto;
}

.papers-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.papers-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
    justify-content: center;
}

.filter-btn {
    padding: 0.75rem 1.5rem;
    border: 2px solid var(--border-color);
    background: var(--surface-color);
    color: var(--text-secondary);
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.filter-btn:hover,
.filter-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.paper-card {
    background: var(--surface-color);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
}

.paper-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
}

.paper-cover {
    height: 250px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.paper-cover::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
}

.paper-icon {
    font-size: 4rem;
    color: white;
    z-index: 1;
    position: relative;
}

.paper-badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
    backdrop-filter: blur(10px);
}

.paper-content {
    padding: 1.5rem;
}

.paper-category {
    color: var(--primary-color);
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.5rem;
}

.paper-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    line-height: 1.4;
}

.paper-description {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.paper-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.paper-meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.paper-tags {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.paper-tag {
    background: rgba(var(--primary-color-rgb), 0.1);
    color: var(--primary-color);
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
}

.download-form {
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
}

.download-form h4 {
    margin: 0 0 1rem 0;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
}

.form-group {
    margin-bottom: 0.75rem;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: var(--surface-color);
    color: var(--text-primary);
    font-size: 0.875rem;
}

.download-btn {
    width: 100%;
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem;
    border-radius: 6px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

.featured-paper {
    grid-column: 1 / -1;
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
    background: linear-gradient(135deg, rgba(var(--primary-color-rgb), 0.05), rgba(var(--secondary-color-rgb), 0.05));
}

.featured-paper .paper-cover {
    height: 350px;
    border-radius: 12px 0 0 12px;
}

.featured-paper .paper-content {
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 2rem;
}

.featured-paper .paper-title {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.featured-paper .paper-description {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
}

.newsletter-signup {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    margin: 3rem 0;
}

.newsletter-signup h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.newsletter-form {
    display: flex;
    gap: 1rem;
    max-width: 400px;
    margin: 1rem auto 0;
}

.newsletter-form input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--background-color);
    color: var(--text-primary);
}

.newsletter-form button {
    padding: 0.75rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: background 0.3s ease;
}

.newsletter-form button:hover {
    background: var(--secondary-color);
}

@media (max-width: 768px) {
    .white-papers-hero h1 {
        font-size: 2rem;
    }
    
    .featured-paper {
        grid-template-columns: 1fr;
    }
    
    .featured-paper .paper-cover {
        border-radius: 12px 12px 0 0;
    }
    
    .papers-filters {
        gap: 0.5rem;
    }
    
    .filter-btn {
        padding: 0.5rem 1rem;
        font-size: 0.875rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .newsletter-form {
        flex-direction: column;
    }
}