body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.4;
    color: #333;
    background-color: #f8f9fa;
    font-size: 14px;
}

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

h1 {
    font-weight: 500;
    font-size: 1.5rem;
    color: #222;
    margin-bottom: 1.2rem;
}

.master-theme {
    background: white;
    padding: 1rem;
    border-radius: 6px;
    margin-bottom: 1rem;
    box-shadow: 0 1px 2px rgba(0,0,0,0.03);
}

.master-theme h2 {
    font-weight: 500;
    font-size: 1.1rem;
    color: #0066cc;
    margin-bottom: 0.8rem;
}

.subthemes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 0.8rem;
}

.subtheme-card {
    background: white;
    padding: 0.6rem;
    border-radius: 4px;
    text-decoration: none;
    color: inherit;
    border: 1px solid #e0e0e0;
    transition: all 0.1s ease;
}

.subtheme-card:hover {
    border-color: #0066cc;
    background-color: #f5f8ff;
}

.subtheme-card h3 {
    font-weight: 400;
    font-size: 0.85rem;
    margin: 0;
    color: #333;
    line-height: 1.3;
}

.article-count {
    font-size: 0.75rem;
    color: #666;
    margin-top: 0.3rem;
    display: inline-block;
    padding: 0.1rem 0.4rem;
    background: #f0f0f0;
    border-radius: 3px;
}