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

:root {
    --color-bg: #fafafa;
    --color-surface: #ffffff;
    --color-text: #1a1a1a;
    --color-text-secondary: #5a5a5a;
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-border: #e5e7eb;
    --color-accent: #f0f4ff;
    --font-body: Georgia, 'Times New Roman', serif;
    --font-heading: system-ui, -apple-system, 'Segoe UI', sans-serif;
    --max-width: 1100px;
    --radius: 8px;
}

html { font-size: 16px; }

body {
    font-family: var(--font-body);
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

.site-header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: 24px 0;
    margin-bottom: 32px;
}

.site-header h1 {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text);
}

.back-link {
    display: inline-block;
    font-family: var(--font-heading);
    font-size: 0.875rem;
    color: var(--color-primary);
    text-decoration: none;
    margin-bottom: 8px;
}

.back-link:hover { text-decoration: underline; }

.main-layout {
    display: grid;
    grid-template-columns: 220px 1fr;
    gap: 32px;
    padding-bottom: 48px;
}

/* Table of Contents */
.toc {
    position: sticky;
    top: 20px;
    align-self: start;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 16px;
    max-height: calc(100vh - 40px);
    overflow-y: auto;
}

.toc h3 {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-secondary);
    margin-bottom: 12px;
}

.toc ul { list-style: none; }

.toc li { margin-bottom: 6px; }

.toc a {
    font-family: var(--font-heading);
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    text-decoration: none;
    display: block;
    padding: 2px 8px;
    border-radius: 4px;
    transition: background 0.15s;
}

.toc a:hover {
    background: var(--color-accent);
    color: var(--color-primary);
}

/* Content area */
.content {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 32px 40px;
    min-width: 0;
}

.article-section {
    margin-bottom: 28px;
    padding-bottom: 28px;
    border-bottom: 1px solid var(--color-border);
}

.article-section:last-child { border-bottom: none; }

.article-section h2 {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--color-primary-dark);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--color-accent);
}

.section-body p {
    margin-bottom: 12px;
}

.section-body ul, .section-body ol {
    margin: 8px 0 16px 20px;
}

.section-body li {
    margin-bottom: 6px;
}

.section-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 16px 0;
    font-size: 0.9rem;
}

.section-body th, .section-body td {
    border: 1px solid var(--color-border);
    padding: 8px 12px;
    text-align: left;
    vertical-align: top;
}

.section-body th {
    background: var(--color-accent);
    font-family: var(--font-heading);
    font-weight: 600;
}

.section-body tr:nth-child(even) {
    background: var(--color-bg);
}

.section-body strong, .leitwort {
    font-weight: 600;
}

.section-body .nowrap {
    white-space: nowrap;
}

/* Media gallery */
.media-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 16px;
}

.media-item {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    overflow: hidden;
}

.media-item img {
    width: 100%;
    height: auto;
    display: block;
}

.media-item figcaption {
    padding: 12px;
    font-size: 0.85rem;
    line-height: 1.5;
}

.media-item figcaption strong {
    font-family: var(--font-heading);
}

.media-item .copyright {
    display: block;
    margin-top: 4px;
    font-size: 0.75rem;
    color: var(--color-text-secondary);
}

.media-item .copyright a {
    color: var(--color-primary);
    text-decoration: underline;
}

/* Index page */
#search-input {
    width: 100%;
    padding: 14px 18px;
    font-size: 1rem;
    font-family: var(--font-heading);
    border: 2px solid var(--color-border);
    border-radius: var(--radius);
    margin-bottom: 20px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

#search-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Category tabs */
.category-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 28px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--color-border);
}

.tab {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    font-family: var(--font-heading);
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.15s;
    white-space: nowrap;
}

.tab:hover {
    background: var(--color-accent);
    border-color: var(--color-primary);
    color: var(--color-primary-dark);
}

.tab.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: #fff;
}

.tab .count {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 20px;
    height: 20px;
    padding: 0 6px;
    font-size: 0.7rem;
    font-weight: 600;
    border-radius: 10px;
    background: rgba(0,0,0,0.08);
}

.tab.active .count {
    background: rgba(255,255,255,0.25);
}

/* Category sections */
.category-section {
    margin-bottom: 36px;
}

.category-heading {
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--color-accent);
}

.cat-icon {
    font-size: 1.3rem;
    line-height: 1;
}

.article-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.article-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 20px;
    transition: box-shadow 0.2s, transform 0.1s;
}

.article-card:hover {
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
    transform: translateY(-1px);
}

.article-card h2 {
    font-family: var(--font-heading);
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.article-card h2 a {
    color: var(--color-primary-dark);
    text-decoration: none;
}

.article-card h2 a:hover {
    text-decoration: underline;
}

.article-card .synonyms {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    margin-bottom: 8px;
}

.article-card .abstract {
    font-size: 0.88rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
    margin-bottom: 12px;
}

.article-card .meta {
    display: flex;
    gap: 12px;
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    font-family: var(--font-heading);
}

.article-card .category {
    background: var(--color-accent);
    padding: 2px 8px;
    border-radius: 4px;
    text-transform: capitalize;
}

/* Footer */
.site-footer {
    text-align: center;
    padding: 24px 0;
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    border-top: 1px solid var(--color-border);
    margin-top: 32px;
}

/* Meta on article page */
.site-header .meta {
    display: flex;
    gap: 12px;
    margin-top: 8px;
    font-family: var(--font-heading);
    font-size: 0.8rem;
    color: var(--color-text-secondary);
}

.site-header .synonyms {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    margin-top: 4px;
}

/* Responsive tables */
.table-wrapper {
    overflow-x: auto;
    margin: 16px 0;
}

.section-body .table-wrapper table {
    min-width: 600px;
}

/* Mobile responsive */
@media (max-width: 900px) {
    .main-layout { grid-template-columns: 1fr; }

    .toc { display: none; }

    .content { padding: 20px 16px; }

    .site-header h1 { font-size: 1.35rem; }

    .article-card h2 { font-size: 1rem; }

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

    .article-section h2 { font-size: 1.15rem; }

    .section-body ul, .section-body ol { margin-left: 16px; }
}

@media (max-width: 480px) {
    .site-header { padding: 16px 0; margin-bottom: 20px; }

    .site-header h1 { font-size: 1.15rem; }

    .container { padding: 0 12px; }

    .content { padding: 16px 12px; border-radius: 6px; }

    .media-gallery { grid-template-columns: 1fr; }

    .article-card { padding: 14px; }

    #search-input { padding: 10px 12px; font-size: 0.95rem; }

    .section-body table { font-size: 0.8rem; }

    .section-body th, .section-body td { padding: 6px 8px; }

    .site-header .meta { flex-wrap: wrap; gap: 6px; }

    .category-tabs { gap: 6px; }
    .tab { font-size: 0.75rem; padding: 6px 10px; }
    .category-heading { font-size: 1rem; }
    .cat-icon { font-size: 1.1rem; }
}