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

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --text-dark: #202122;
    --text-medium: #54595d;
    --text-light: #72777d;
    --border-color: #a2a9b1;
    --border-light: #c8ccd1;
    --link-blue: #0645ad;
    --link-visited: #0b0080;
    --link-hover: #0b0080;
}

body {
    font-family: Georgia, 'Times New Roman', serif;
    font-size: 16px;
    line-height: 1.8;
    color: var(--text-dark);
    background: var(--bg-secondary);
}

a {
    color: var(--link-blue);
    text-decoration: none;
    transition: color 0.2s;
}

a:visited {
    color: var(--link-visited);
}

a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

.site-header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-light);
    padding: 12px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.header-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.site-logo {
    font-family: Arial, sans-serif;
    font-size: 20px;
    font-weight: bold;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 8px;
}

.site-logo i {
    color: var(--text-medium);
    font-size: 22px;
}

.main-nav ul {
    list-style: none;
    display: flex;
    gap: 24px;
    font-family: Arial, sans-serif;
    font-size: 14px;
}

.main-nav a {
    color: var(--text-dark);
    padding: 6px 0;
}

.main-nav a:hover {
    text-decoration: none;
    color: var(--link-blue);
}

.mobile-toggle {
    display: none;
    background: none;
    border: 1px solid var(--border-color);
    padding: 6px 10px;
    cursor: pointer;
    border-radius: 3px;
    font-size: 18px;
    color: var(--text-dark);
}

.page-container {
    max-width: 1280px;
    margin: 24px auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 1fr 280px;
    gap: 32px;
    align-items: start;
}

.main-content {
    background: var(--bg-primary);
    padding: 32px;
    border: 1px solid var(--border-light);
    border-radius: 2px;
}

.page-title {
    font-family: 'Linux Libertine', Georgia, serif;
    font-size: 32px;
    font-weight: normal;
    line-height: 1.3;
    margin-bottom: 8px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-dark);
}

.page-subtitle {
    font-family: Arial, sans-serif;
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 20px;
}

.article-intro {
    font-size: 16px;
    margin-bottom: 24px;
}

.article-intro::first-letter {
    font-size: 200%;
    font-weight: bold;
    line-height: 1;
}

.table-of-contents {
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    padding: 16px;
    margin: 24px 0;
    max-width: 400px;
}

.table-of-contents h3 {
    font-family: Arial, sans-serif;
    font-size: 16px;
    font-weight: bold;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.table-of-contents ol {
    margin-left: 20px;
    font-family: Arial, sans-serif;
    font-size: 14px;
}

.table-of-contents li {
    margin-bottom: 6px;
    line-height: 1.5;
}

.article-section {
    margin-top: 32px;
    margin-bottom: 28px;
}

.article-section h2 {
    font-family: 'Linux Libertine', Georgia, serif;
    font-size: 24px;
    font-weight: normal;
    margin-bottom: 16px;
    padding-bottom: 4px;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-dark);
}

.article-section h3 {
    font-family: 'Linux Libertine', Georgia, serif;
    font-size: 20px;
    font-weight: 600;
    margin-top: 24px;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.article-section h4 {
    font-family: Arial, sans-serif;
    font-size: 16px;
    font-weight: bold;
    margin-top: 18px;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.article-section p {
    margin-bottom: 14px;
    text-align: justify;
}

.article-section ul,
.article-section ol {
    margin: 14px 0 14px 36px;
}

.article-section li {
    margin-bottom: 8px;
}

.info-sidebar {
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    padding: 16px;
    position: sticky;
    top: 80px;
}

.info-sidebar h3 {
    font-family: Arial, sans-serif;
    font-size: 16px;
    font-weight: bold;
    margin-bottom: 14px;
    text-align: center;
    color: var(--text-dark);
}

.info-sidebar-content {
    font-family: Arial, sans-serif;
    font-size: 13px;
    line-height: 1.6;
}

.info-row {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-light);
}

.info-row:last-child {
    border-bottom: none;
}

.info-label {
    font-weight: bold;
    color: var(--text-medium);
    display: block;
    margin-bottom: 4px;
}

.info-value {
    color: var(--text-dark);
}

.sidebar-image {
    width: 100%;
    height: auto;
    margin-bottom: 12px;
    border: 1px solid var(--border-light);
    background: var(--bg-primary);
}

.references {
    margin-top: 36px;
    padding-top: 24px;
    border-top: 2px solid var(--border-light);
}

.references h3 {
    font-family: 'Linux Libertine', Georgia, serif;
    font-size: 20px;
    font-weight: normal;
    margin-bottom: 14px;
}

.references ol {
    font-family: Arial, sans-serif;
    font-size: 13px;
    line-height: 1.7;
    margin-left: 24px;
}

.references li {
    margin-bottom: 10px;
}

.cta-banner {
    background: #eaecf0;
    border: 1px solid var(--border-color);
    padding: 20px;
    margin: 28px 0;
    text-align: center;
    border-radius: 3px;
}

.cta-banner h3 {
    font-family: Arial, sans-serif;
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.cta-banner p {
    font-family: Arial, sans-serif;
    font-size: 14px;
    color: var(--text-medium);
    margin-bottom: 16px;
}

.btn-primary {
    display: inline-block;
    background: #36c;
    color: #fff;
    padding: 10px 24px;
    border-radius: 3px;
    font-family: Arial, sans-serif;
    font-size: 14px;
    font-weight: bold;
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    background: #2a4b8d;
    color: #fff;
    text-decoration: none;
}

.breadcrumb {
    font-family: Arial, sans-serif;
    font-size: 13px;
    margin-bottom: 14px;
    color: var(--text-light);
}

.breadcrumb a {
    color: var(--link-blue);
}

.site-footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border-light);
    padding: 32px 0;
    margin-top: 48px;
    font-family: Arial, sans-serif;
}

.footer-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 48px;
}

.footer-section h4 {
    font-size: 15px;
    font-weight: bold;
    margin-bottom: 14px;
    color: var(--text-dark);
}

.footer-section p,
.footer-section li {
    font-size: 13px;
    line-height: 1.7;
    color: var(--text-medium);
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: 8px;
}

.footer-social {
    display: flex;
    gap: 12px;
    margin-top: 12px;
}

.footer-social a {
    display: inline-block;
    width: 32px;
    height: 32px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    border-radius: 3px;
    text-align: center;
    line-height: 32px;
    color: var(--text-medium);
    font-size: 14px;
}

.footer-social a:hover {
    background: var(--link-blue);
    border-color: var(--link-blue);
    color: #fff;
    text-decoration: none;
}

.footer-bottom {
    max-width: 1280px;
    margin: 24px auto 0;
    padding: 24px 24px 0;
    border-top: 1px solid var(--border-light);
    text-align: center;
    font-size: 12px;
    color: var(--text-light);
}

.contact-info {
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    padding: 20px;
    margin: 20px 0;
}

.contact-info h3 {
    font-size: 18px;
    margin-bottom: 14px;
}

.contact-item {
    display: flex;
    align-items: start;
    gap: 12px;
    margin-bottom: 14px;
    font-family: Arial, sans-serif;
    font-size: 14px;
}

.contact-item i {
    color: var(--text-medium);
    width: 20px;
    margin-top: 2px;
}

.faq-item {
    margin-bottom: 28px;
}

.faq-question {
    font-family: Arial, sans-serif;
    font-size: 17px;
    font-weight: bold;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.faq-answer {
    font-size: 15px;
    line-height: 1.7;
    color: var(--text-medium);
}

.error-page {
    text-align: center;
    padding: 80px 20px;
}

.error-page h1 {
    font-size: 72px;
    font-weight: bold;
    color: var(--text-medium);
    margin-bottom: 16px;
}

.error-page h2 {
    font-size: 28px;
    margin-bottom: 12px;
}

.error-page p {
    font-size: 16px;
    color: var(--text-medium);
    margin-bottom: 24px;
}

@media (max-width: 968px) {
    .page-container {
        grid-template-columns: 1fr;
    }

    .info-sidebar {
        position: static;
        max-width: 100%;
    }

    .main-nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        border-bottom: 1px solid var(--border-light);
        padding: 16px;
    }

    .main-nav.active {
        display: block;
    }

    .main-nav ul {
        flex-direction: column;
        gap: 12px;
    }

    .mobile-toggle {
        display: block;
    }

    .footer-container {
        grid-template-columns: 1fr;
        gap: 28px;
    }

    .main-content {
        padding: 20px;
    }

    .page-title {
        font-size: 26px;
    }
}

@media (max-width: 640px) {
    .header-container {
        padding: 0 16px;
    }

    .page-container {
        margin: 16px auto;
        padding: 0 16px;
    }

    .main-content {
        padding: 16px;
    }

    .page-title {
        font-size: 24px;
    }

    .article-section h2 {
        font-size: 20px;
    }

    .article-section h3 {
        font-size: 18px;
    }

    .table-of-contents {
        max-width: 100%;
    }
}