:root {
    --primary: #2563eb;
    --bg-light: #ffffff;
    --bg-card: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
}

body {
    background: var(--bg-light);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
}

.navbar {
    background: var(--bg-light) !important;
    border-bottom: 1px solid var(--border);
}

.navbar-brand, .nav-link {
    color: var(--text-primary) !important;
}

.nav-link:hover {
    color: var(--primary) !important;
}

.nav-link.active {
    color: var(--primary) !important;
}

.article-header {
    padding: 48px 0 32px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 32px;
}

.article-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.article-header .meta {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.container-main {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px 60px;
}

.article-nav {
    display: flex;
    gap: 12px;
    margin-bottom: 32px;
    font-size: 0.875rem;
}

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

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

.article-section {
    margin-bottom: 32px;
}

.article-section h2 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.article-section h3 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 16px 0 8px;
}

.article-section p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 12px;
}

.article-section ul, .article-section ol {
    color: var(--text-secondary);
    font-size: 0.95rem;
    padding-left: 20px;
    margin-bottom: 12px;
}

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

.article-section strong {
    color: var(--text-primary);
}

.algo-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 16px;
    margin-bottom: 12px;
}

.algo-card h4 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 6px;
}

.algo-card p {
    font-size: 0.875rem;
    margin-bottom: 0;
}

.formula-block {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 12px 16px;
    margin: 12px 0;
    font-family: 'Courier New', monospace;
    font-size: 0.85rem;
    overflow-x: auto;
}

.complexity-table {
    width: 100%;
    border-collapse: collapse;
    margin: 16px 0;
    font-size: 0.875rem;
}

.complexity-table th, .complexity-table td {
    border: 1px solid var(--border);
    padding: 10px 12px;
    text-align: left;
}

.complexity-table th {
    background: var(--bg-card);
    font-weight: 600;
    color: var(--text-primary);
}

.complexity-table td {
    color: var(--text-secondary);
}

.project-list {
    display: grid;
    gap: 12px;
}

.project-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 14px 16px;
}

.project-item h4 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.project-item h4 a {
    color: var(--primary);
    text-decoration: none;
}

.project-item h4 a:hover {
    text-decoration: underline;
}

.project-item p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

.ref-list {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 16px;
}

.ref-list h4 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.ref-list ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.ref-list li {
    margin-bottom: 8px;
    padding-left: 0;
    font-size: 0.85rem;
}

.ref-list a {
    color: var(--primary);
    text-decoration: none;
    word-break: break-all;
}

.ref-list a:hover {
    text-decoration: underline;
}

footer {
    text-align: center;
    padding: 32px 0;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

footer a {
    color: var(--primary);
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}