:root {
    --bg: #0a0a0f; --bg-card: #111118; --bg-card-hover: #1a1a24;
    --border: #1e1e2a; --border-hover: #6366f1;
    --text: #e0e0e5; --text-secondary: #71717a; --text-tertiary: #52525b;
    --heading: #fff; --nav-bg: rgba(10,10,15,0.85);
    --accent: #6366f1; --accent-light: #a5b4fc;
    --cta-bg: #4f46e5; --cta-hover: #4338ca;
    --step-bg: rgba(99,102,241,0.15); --step-color: #818cf8;
}
[data-theme="light"] {
    --bg: #fafafa; --bg-card: #fff; --bg-card-hover: #f5f5ff;
    --border: #e5e5ea; --border-hover: #6366f1;
    --text: #333; --text-secondary: #666; --text-tertiary: #999;
    --heading: #111; --nav-bg: rgba(250,250,250,0.9);
    --accent: #6366f1; --accent-light: #4f46e5;
    --cta-bg: #4f46e5; --cta-hover: #4338ca;
    --step-bg: rgba(99,102,241,0.1); --step-color: #6366f1;
}
        * { margin: 0; padding: 0; box-sizing: border-box; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: var(--bg);
            color: var(--text);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }
        .container {
            max-width: 720px;
            margin: 0 auto;
            padding: 0 24px;
            width: 100%;
        }
        header {
            padding: 20px 0;
            border-bottom: 1px solid var(--border);
        }
        header .container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .logo {
            font-size: 20px;
            font-weight: 700;
            color: var(--heading);
            text-decoration: none;
            letter-spacing: -0.5px;
        }
        .logo span { color: var(--accent); }
        .nav-right {
            display: flex;
            align-items: center;
            gap: 24px;
        }
        nav a {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 14px;
            margin-left: 32px;
            transition: color 0.2s;
        }
        nav a:first-child { margin-left: 0; }
        nav a:hover { color: var(--heading); }
        .nav-dropdown {
            position: relative;
            display: inline-block;
            margin-left: 32px;
        }
        .nav-dropdown > a, .nav-dropdown-toggle {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 14px;
            transition: color 0.2s;
            cursor: pointer;
            display: inline-flex;
            align-items: center;
            gap: 4px;
        }
        .nav-dropdown > a:hover, .nav-dropdown-toggle:hover { color: var(--heading); }
        .nav-dropdown > a::after, .nav-dropdown-toggle::after {
            content: '';
            border-left: 4px solid transparent;
            border-right: 4px solid transparent;
            border-top: 4px solid currentColor;
            margin-top: 2px;
        }
        .nav-dropdown-toggle { background: none; border: none; font-family: inherit; }
        .nav-dropdown-menu {
            display: none;
            position: absolute;
            top: 100%;
            right: 0;
            margin-top: 8px;
            background: var(--bg-card);
            border: 1px solid var(--border);
            border-radius: 8px;
            padding: 6px 0;
            min-width: 200px;
            z-index: 100;
        }
        .nav-dropdown-menu.open { display: block; }
        .nav-dropdown-menu a {
            display: flex;
            align-items: center;
            gap: 10px;
            padding: 10px 16px;
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 14px;
            transition: all 0.15s;
            white-space: nowrap;
            margin-left: 0;
        }
        .nav-dropdown-menu a:hover {
            background: var(--bg-card-hover);
            color: var(--heading);
        }
        .nav-dropdown-menu .item-icon {
            width: 28px;
            height: 28px;
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 14px;
            flex-shrink: 0;
        }
        .nav-dropdown-menu .item-info {
            display: flex;
            flex-direction: column;
        }
        .nav-dropdown-menu .item-name {
            font-weight: 500;
            color: var(--text);
        }
        .nav-dropdown-menu .item-desc {
            font-size: 11px;
            color: var(--text-tertiary);
            margin-top: 1px;
        }
        .icon-btn { background: none; border: none; cursor: pointer; padding: 6px; border-radius: 6px; display: flex; align-items: center; transition: background 0.2s; color: var(--text-secondary); }
.icon-btn:hover { background: var(--bg-card); }
.icon-btn svg { width: 20px; height: 20px; }
        .lang-btn {
            background: none;
            border: none;
            cursor: pointer;
            padding: 4px;
            display: flex;
            align-items: center;
            opacity: 0.7;
            transition: opacity 0.2s;
        }
        .lang-btn:hover { opacity: 1; }
        .lang-btn svg { width: 22px; height: 22px; }

        .breadcrumb {
            padding: 20px 0 0;
            font-size: 13px;
            color: var(--text-tertiary);
        }
        .breadcrumb a {
            color: var(--text-secondary);
            text-decoration: none;
            transition: color 0.2s;
        }
        .breadcrumb a:hover { color: var(--accent); }
        .breadcrumb .sep { margin: 0 6px; color: #3f3f46; }

        .article-header {
            padding: 32px 0 8px;
        }
        .article-header h1 {
            font-size: 32px;
            font-weight: 800;
            letter-spacing: -0.5px;
            color: var(--heading);
            line-height: 1.3;
        }
        .article-meta {
            margin-top: 12px;
            font-size: 13px;
            color: var(--text-tertiary);
            display: flex;
            gap: 16px;
        }
        .article-meta .category {
            background: var(--step-bg);
            color: var(--accent-light);
            padding: 2px 10px;
            border-radius: 4px;
            font-size: 12px;
            font-weight: 500;
        }

        .article-body {
            padding: 32px 0 48px;
        }
        .article-body h2 {
            font-size: 24px;
            font-weight: 700;
            color: var(--heading);
            margin-top: 32px;
            margin-bottom: 12px;
        }
        .article-body h3 {
            font-size: 18px;
            font-weight: 600;
            color: var(--text);
            margin-top: 20px;
            margin-bottom: 8px;
        }
        .article-body p {
            font-size: 15px;
            color: var(--text-secondary);
            line-height: 1.8;
            margin-bottom: 12px;
        }
        .article-body ul, .article-body ol {
            color: var(--text-secondary);
            padding-left: 24px;
            margin-bottom: 12px;
            font-size: 15px;
            line-height: 1.8;
        }
        .article-body li { margin-bottom: 4px; }
        .article-body code {
            background: var(--bg-card-hover);
            color: var(--text);
            padding: 2px 6px;
            border-radius: 4px;
            font-size: 13px;
            font-family: 'SF Mono', 'Fira Code', monospace;
        }
        .article-body pre {
            background: var(--bg-card-hover);
            color: var(--text);
            border-radius: 6px;
            padding: 16px;
            overflow-x: auto;
            margin-bottom: 16px;
            font-size: 13px;
            line-height: 1.6;
            font-family: 'SF Mono', 'Fira Code', monospace;
        }
        .article-body pre code {
            background: none;
            padding: 0;
            font-size: inherit;
        }
        .article-body img {
            max-width: 600px;
            width: 100%;
            max-height: 400px;
            object-fit: contain;
            height: auto;
            border-radius: 8px;
            margin: 16px 0;
            background: var(--bg-card);
        }
        .article-body table {
            width: 100%;
            border-collapse: collapse;
            margin-bottom: 16px;
        }
        .article-body th {
            color: var(--text-tertiary);
            font-weight: 600;
            font-size: 13px;
            text-align: left;
            padding: 8px 12px;
            border-bottom: 1px solid var(--border);
        }
        .article-body td {
            color: var(--text-secondary);
            font-size: 14px;
            padding: 8px 12px;
            border-bottom: 1px solid var(--border);
        }
        .article-body blockquote {
            border-left: 3px solid var(--accent);
            padding-left: 16px;
            margin: 32px 0;
        }
        .article-body blockquote p {
            color: var(--text);
            font-size: 15px;
        }
        .article-body blockquote a {
            color: var(--accent);
            text-decoration: none;
        }
        .article-body blockquote a:hover {
            text-decoration: underline;
        }

        .back-link {
            display: inline-block;
            margin-top: 24px;
            color: var(--accent);
            text-decoration: none;
            font-size: 14px;
            transition: color 0.2s;
        }
        .back-link:hover { color: var(--accent-light); }

        footer {
            margin-top: auto;
            padding: 32px 0;
            border-top: 1px solid var(--border);
            text-align: center;
        }
        footer p {
            font-size: 13px;
            color: var(--text-secondary);
        }
        footer a {
            color: var(--text-secondary);
            text-decoration: underline;
            transition: color 0.2s;
        }
        footer a:hover { color: var(--heading); }

        .feature-grid {
            display: grid;
            grid-template-columns: 1fr;
            gap: 12px;
            margin: 16px 0 32px;
        }
        .feature-card {
            background: var(--bg-card);
            border: 1px solid var(--border);
            border-radius: 10px;
            padding: 14px 18px;
            display: flex;
            align-items: flex-start;
            gap: 14px;
            transition: border-color 0.2s, background 0.2s;
        }
        .feature-card:hover {
            border-color: var(--border-hover);
            background: var(--bg-card-hover);
        }
        .feature-icon {
            font-size: 22px;
            line-height: 1;
            flex-shrink: 0;
            width: 32px;
            text-align: center;
            padding-top: 2px;
        }
        .feature-title {
            font-size: 14px;
            font-weight: 600;
            color: var(--heading);
            margin: 0 0 3px;
        }
        .feature-desc {
            font-size: 13px;
            color: var(--text-secondary);
            margin: 0;
            line-height: 1.6;
        }
        @media (min-width: 640px) {
            .feature-grid {
                grid-template-columns: 1fr 1fr;
            }
        }
        @media (max-width: 640px) {
            .article-header h1 { font-size: 24px; }
            .article-body h2 { font-size: 20px; }
        }