:root {
    --sidebar-width: 280px;
    --header-height: 56px;
    --toc-width: 220px;
    --sidebar-bg: #1b1b2f;
    --sidebar-text: #c5c6d0;
    --sidebar-hover: #2d2d44;
    --sidebar-active: #3b82f6;
    --header-bg: #ffffff;
    --content-bg: #ffffff;
    --body-bg: #f8f9fa;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --link-color: #2563eb;
    --link-hover: #1d4ed8;
    --code-bg: #f3f4f6;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-height) + 20px);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-primary);
    background: var(--body-bg);
    line-height: 1.6;
}

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--header-bg);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    display: flex;
    align-items: center;
    padding: 0 20px;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 20px;
}

.site-logo {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
}

.site-logo span {
    color: var(--sidebar-active);
}

.header-search {
    position: relative;
}

.header-search input {
    width: 300px;
    padding: 7px 12px 7px 36px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
    background: var(--body-bg);
    color: var(--text-primary);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.header-search input:focus {
    outline: none;
    border-color: var(--sidebar-active);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.header-search svg {
    position: absolute;
    left: 10px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    width: 16px;
    height: 16px;
}

.search-suggestions {
    position: absolute;
    top: calc(100% + 6px);
    left: 0;
    right: 0;
    background: var(--content-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
    overflow: hidden;
    z-index: 110;
}

.search-suggestions.hidden {
    display: none;
}

.search-suggestion-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 10px 14px;
    text-decoration: none;
    border-bottom: 1px solid var(--border-color);
}

.search-suggestion-item:last-child {
    border-bottom: none;
}

.search-suggestion-item:hover {
    background: var(--body-bg);
}

.search-suggestion-title {
    font-size: 14px;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.search-suggestion-category {
    font-size: 11px;
    color: var(--sidebar-active);
    background: #eff6ff;
    padding: 2px 8px;
    border-radius: 4px;
    flex-shrink: 0;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.lang-switcher {
    display: flex;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    overflow: hidden;
}

.lang-switcher a {
    padding: 5px 12px;
    font-size: 13px;
    text-decoration: none;
    color: var(--text-secondary);
    transition: all 0.2s;
}

.lang-switcher a.active {
    background: var(--sidebar-active);
    color: #fff;
}

.lang-switcher a:not(.active):hover {
    background: var(--body-bg);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    color: var(--text-primary);
}

/* Sidebar */
.sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--sidebar-bg);
    overflow-y: auto;
    padding: 16px 0;
    z-index: 90;
    transition: transform 0.3s ease;
}

.sidebar::-webkit-scrollbar {
    width: 4px;
}

.sidebar::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.15);
    border-radius: 2px;
}

.sidebar-section {
    margin-bottom: 4px;
}

.sidebar-category {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 20px;
    color: var(--sidebar-text);
    font-size: 13px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    cursor: pointer;
    transition: color 0.2s;
    user-select: none;
}

.sidebar-category:hover {
    color: #fff;
}

.sidebar-category .arrow {
    transition: transform 0.2s;
    font-size: 10px;
}

.sidebar-category.open .arrow {
    transform: rotate(90deg);
}

.sidebar-pages {
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.3s ease;
}

.sidebar-pages.open {
    max-height: 2000px;
}

.sidebar-link {
    display: block;
    padding: 6px 20px 6px 32px;
    color: var(--sidebar-text);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.15s;
    border-left: 3px solid transparent;
}

.sidebar-link:hover {
    color: #fff;
    background: var(--sidebar-hover);
}

.sidebar-link.active {
    color: #fff;
    background: var(--sidebar-hover);
    border-left-color: var(--sidebar-active);
}

.sidebar-sub-link {
    padding-left: 44px;
    font-size: 13px;
}

/* Main content */
.main-content {
    margin-left: var(--sidebar-width);
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height));
    display: flex;
}

.content-area {
    flex: 1;
    max-width: 900px;
    padding: 32px 48px;
    background: var(--content-bg);
    min-height: calc(100vh - var(--header-height));
}

/* Breadcrumbs */
.breadcrumbs {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.breadcrumbs a {
    color: var(--link-color);
    text-decoration: none;
}

.breadcrumbs a:hover {
    text-decoration: underline;
}

.breadcrumbs .separator {
    color: var(--border-color);
}

/* Page content typography */
.page-title {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
    line-height: 1.3;
}

.page-meta {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 32px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.page-content h1 { font-size: 28px; font-weight: 700; margin: 32px 0 16px; color: var(--text-primary); }
.page-content h2 { font-size: 24px; font-weight: 600; margin: 28px 0 14px; color: var(--text-primary); padding-bottom: 8px; border-bottom: 1px solid var(--border-color); }
.page-content h3 { font-size: 20px; font-weight: 600; margin: 24px 0 12px; color: var(--text-primary); }
.page-content h4 { font-size: 16px; font-weight: 600; margin: 20px 0 10px; color: var(--text-primary); }

.page-content p { margin: 0 0 16px; }
.page-content a { color: var(--link-color); text-decoration: none; }
.page-content a:hover { text-decoration: underline; }

.page-content ul, .page-content ol { margin: 0 0 16px; padding-left: 24px; }
.page-content li { margin-bottom: 4px; }

.page-content code {
    background: var(--code-bg);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    font-family: "SF Mono", "Fira Code", Consolas, monospace;
}

.page-content pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 16px 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 0 0 16px;
    font-size: 14px;
    line-height: 1.5;
}

.page-content pre code {
    background: none;
    padding: 0;
    color: inherit;
    font-family: "SF Mono", "Fira Code", Consolas, monospace;
}

/* Terminal-style command blocks */
.code-block {
    margin: 0 0 16px;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}

.code-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #0f172a;
    padding: 8px 14px;
    border-bottom: 1px solid rgba(255,255,255,0.06);
}

.code-block-lang {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: #94a3b8;
}

.code-copy-btn {
    background: rgba(255,255,255,0.08);
    color: #cbd5e1;
    border: none;
    border-radius: 4px;
    padding: 4px 10px;
    font-size: 12px;
    cursor: pointer;
    transition: background 0.15s, color 0.15s;
}

.code-copy-btn:hover {
    background: rgba(255,255,255,0.16);
    color: #fff;
}

.code-copy-btn.copied {
    background: #16a34a;
    color: #fff;
}

.code-block pre {
    margin: 0;
    border-radius: 0;
}

.page-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 0 0 16px;
    font-size: 14px;
}

.page-content th, .page-content td {
    padding: 10px 14px;
    border: 1px solid var(--border-color);
    text-align: left;
}

.page-content th {
    background: var(--body-bg);
    font-weight: 600;
}

.page-content img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 8px 0;
}

.page-content blockquote {
    border-left: 4px solid var(--sidebar-active);
    padding: 12px 20px;
    margin: 0 0 16px;
    background: #eff6ff;
    border-radius: 0 6px 6px 0;
    color: #1e40af;
}

/* Callout boxes */
.page-content .callout {
    padding: 14px 20px;
    margin: 0 0 16px;
    border-radius: 0 6px 6px 0;
    border-left: 4px solid;
}

.page-content .callout p:last-child {
    margin-bottom: 0;
}

.page-content .callout-note {
    background: #eff6ff;
    border-color: #3b82f6;
    color: #1e3a5f;
}

.page-content .callout-warning {
    background: #fffbeb;
    border-color: #f59e0b;
    color: #7c4a03;
}

.page-content .callout-info {
    background: #f3f4f6;
    border-color: #6b7280;
    color: #374151;
}

/* Collapsible sections */
.page-content details {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 12px 20px;
    margin: 0 0 16px;
}

.page-content details[open] summary {
    margin-bottom: 8px;
}

.page-content details summary {
    font-weight: 600;
    cursor: pointer;
    color: var(--text-primary);
}

.page-content details summary::marker {
    color: var(--sidebar-active);
}

/* Tabs */
.page-content .doc-tabs {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin: 0 0 16px;
    overflow: hidden;
}

.doc-tabs-nav {
    display: flex;
    background: var(--body-bg);
    border-bottom: 1px solid var(--border-color);
    overflow-x: auto;
}

.doc-tab-btn {
    padding: 10px 20px;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
    white-space: nowrap;
    border-bottom: 2px solid transparent;
    transition: color 0.15s, border-color 0.15s;
}

.doc-tab-btn:hover {
    color: var(--text-primary);
}

.doc-tab-btn.active {
    color: var(--sidebar-active);
    border-bottom-color: var(--sidebar-active);
}

.doc-tab-panel {
    padding: 16px 20px;
}

.doc-tab-panel > *:last-child {
    margin-bottom: 0;
}

/* Responsive video embeds */
.page-content iframe {
    max-width: 100%;
    width: 100%;
    aspect-ratio: 16 / 9;
    height: auto;
    border: none;
    border-radius: 8px;
    margin: 0 0 16px;
}

/* Download attachments */
.doc-download {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    margin: 0 0 16px;
    background: var(--body-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-primary);
    font-size: 14px;
    font-weight: 500;
    transition: border-color 0.15s, background 0.15s;
}

.doc-download:hover {
    border-color: var(--sidebar-active);
    background: #eff6ff;
    text-decoration: none;
}

/* Tags */
.page-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 0 0 24px;
}

.tag-chip {
    display: inline-block;
    padding: 4px 12px;
    background: var(--code-bg);
    border-radius: 999px;
    font-size: 13px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: background 0.15s, color 0.15s;
}

.tag-chip:hover {
    background: var(--sidebar-active);
    color: #fff;
    text-decoration: none;
}

/* Prev/next navigation */
.page-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin: 32px 0 0;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.page-nav-link {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 14px 18px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    text-decoration: none;
    transition: border-color 0.15s, background 0.15s;
}

.page-nav-link:hover {
    border-color: var(--sidebar-active);
    background: #eff6ff;
    text-decoration: none;
}

.page-nav-next {
    grid-column: 2;
    text-align: right;
    align-items: flex-end;
}

.page-nav-label {
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
}

.page-nav-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--link-color);
}

/* Related articles */
.related-articles {
    margin: 24px 0 0;
}

.related-title {
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.related-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.related-link {
    padding: 10px 16px;
    background: var(--body-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
    color: var(--text-primary);
    text-decoration: none;
    transition: border-color 0.15s;
}

.related-link:hover {
    border-color: var(--sidebar-active);
    color: var(--link-color);
    text-decoration: none;
}

/* Table of Contents */
.toc {
    position: sticky;
    top: calc(var(--header-height) + 32px);
    width: var(--toc-width);
    padding: 0 20px;
    align-self: flex-start;
    flex-shrink: 0;
}

.toc-title {
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.toc-list {
    list-style: none;
    padding: 0;
    border-left: 2px solid var(--border-color);
}

.toc-list li {
    margin: 0;
}

.toc-list a {
    display: block;
    padding: 4px 0 4px 16px;
    font-size: 13px;
    color: var(--text-secondary);
    text-decoration: none;
    border-left: 2px solid transparent;
    margin-left: -2px;
    transition: all 0.15s;
}

.toc-list a:hover {
    color: var(--link-color);
}

.toc-list a.active {
    color: var(--sidebar-active);
    border-left-color: var(--sidebar-active);
}

.toc-list .toc-h3 {
    padding-left: 28px;
}

/* Welcome/Landing page */
.welcome-hero {
    text-align: center;
    padding: 60px 20px;
}

.welcome-hero h1 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 16px;
}

.welcome-hero p {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 40px;
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    padding: 0 20px 40px;
}

.category-card {
    background: var(--content-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 24px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.2s;
}

.category-card:hover {
    border-color: var(--sidebar-active);
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    transform: translateY(-2px);
}

.category-card h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
}

.category-card p {
    font-size: 14px;
    color: var(--text-secondary);
}

/* Search results */
.search-results {
    padding: 32px 48px;
}

.search-result {
    padding: 16px 0;
    border-bottom: 1px solid var(--border-color);
}

.search-result h3 {
    margin-bottom: 4px;
}

.search-result h3 a {
    color: var(--link-color);
    text-decoration: none;
    font-size: 16px;
}

.search-result h3 a:hover {
    text-decoration: underline;
}

.search-result .excerpt {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.5;
}

.search-result .category-tag {
    display: inline-block;
    font-size: 12px;
    color: var(--sidebar-active);
    background: #eff6ff;
    padding: 2px 8px;
    border-radius: 4px;
    margin-top: 6px;
}

.search-result mark {
    background: #fef08a;
    color: inherit;
    padding: 0 2px;
    border-radius: 2px;
}

/* Sidebar overlay for mobile */
.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 80;
}

/* Footer */
.site-footer {
    margin-left: var(--sidebar-width);
    padding: 32px 48px;
    border-top: 1px solid var(--border-color);
    background: var(--content-bg);
}

.footer-inner {
    max-width: 900px;
    text-align: center;
}

.footer-brand {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.footer-brand span {
    color: var(--sidebar-active);
}

.footer-tagline {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 12px;
}

.footer-links a {
    font-size: 13px;
    color: var(--link-color);
    text-decoration: none;
}

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

.footer-copyright {
    font-size: 12px;
    color: var(--text-secondary);
}

/* Responsive */
@media (max-width: 1100px) {
    .toc {
        display: none;
    }
}

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }

    .header-search input {
        width: 160px;
    }

    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .sidebar-overlay.open {
        display: block;
    }

    .main-content {
        margin-left: 0;
    }

    .site-footer {
        margin-left: 0;
        padding: 24px 16px;
    }

    .content-area {
        padding: 24px 16px;
    }

    .welcome-hero {
        padding: 32px 16px;
    }

    .welcome-hero h1 {
        font-size: 24px;
    }

    .category-grid {
        grid-template-columns: 1fr;
        padding: 0 16px 32px;
    }

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

    .search-results {
        padding: 24px 16px;
    }

    .page-nav {
        grid-template-columns: 1fr;
    }

    .page-nav-next {
        grid-column: 1;
        text-align: left;
        align-items: flex-start;
    }
}