:root {
            --bg-dark: #0a0a0f;
            --bg-card: #12121a;
            --bg-code: #1a1a2e;
            --neon-cyan: #00f5ff;
            --neon-magenta: #ff00ff;
            --neon-purple: #b366ff;
            --text-primary: #ffffff;
            --text-secondary: #a0a0b0;
            --border-color: #2a2a3a;
            --success-green: #4ec9b0;
            --warning-yellow: #dcdcaa;
        }
        * { margin: 0; padding: 0; box-sizing: border-box; }
        body { font-family: 'Space Grotesk', sans-serif; background: var(--bg-dark); color: var(--text-primary); line-height: 1.7; min-height: 100vh; }
        body::before { content: ''; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: linear-gradient(90deg, rgba(0,245,255,0.03) 1px, transparent 1px), linear-gradient(rgba(0,245,255,0.03) 1px, transparent 1px); background-size: 50px 50px; pointer-events: none; z-index: -1; }
        .header { background: var(--bg-card); border-bottom: 1px solid var(--border-color); padding: 1rem 2rem; position: sticky; top: 0; z-index: 100; }
        .header-content { max-width: 1200px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
        .header-brand { display: flex; align-items: center; gap: 1rem; text-decoration: none; color: var(--text-primary); }
        .header-brand:hover { color: var(--neon-cyan); }
        .header-title { font-size: 1.25rem; font-weight: 600; background: linear-gradient(135deg, var(--neon-cyan), var(--neon-magenta)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
        .header-nav { display: flex; gap: 0.5rem; }
        .nav-btn { display: inline-flex; align-items: center; gap: 0.5rem; padding: 0.5rem 1rem; background: transparent; border: 1px solid var(--border-color); border-radius: 6px; color: var(--text-secondary); text-decoration: none; font-size: 0.875rem; transition: all 0.2s ease; cursor: pointer; font-family: inherit; }
        .nav-btn:hover:not(:disabled) { border-color: var(--neon-cyan); color: var(--neon-cyan); }
        .nav-btn:disabled { opacity: 0.4; cursor: not-allowed; }
        .layout { display: flex; max-width: 1400px; margin: 0 auto; }
        .sidebar { width: 280px; background: var(--bg-card); border-right: 1px solid var(--border-color); height: calc(100vh - 65px); position: sticky; top: 65px; overflow-y: auto; flex-shrink: 0; }
        .sidebar-section { padding: 1rem; }
        .sidebar-title { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--text-secondary); margin-bottom: 0.75rem; padding: 0 0.5rem; }
        .step-link { display: flex; align-items: center; gap: 0.75rem; padding: 0.625rem 0.75rem; border-radius: 6px; text-decoration: none; color: var(--text-secondary); font-size: 0.875rem; transition: all 0.2s ease; margin-bottom: 0.25rem; }
        .step-link:hover { background: rgba(0,245,255,0.1); color: var(--text-primary); }
        .step-link.active { background: linear-gradient(135deg, rgba(0,245,255,0.2), rgba(255,0,255,0.2)); color: var(--text-primary); border-left: 3px solid var(--neon-cyan); }
        .step-number { width: 24px; height: 24px; display: flex; align-items: center; justify-content: center; background: var(--border-color); border-radius: 6px; font-size: 0.75rem; font-weight: 600; font-family: 'JetBrains Mono', monospace; flex-shrink: 0; }
        .step-link.active .step-number { background: linear-gradient(135deg, var(--neon-cyan), var(--neon-magenta)); color: var(--bg-dark); }
        .main { flex: 1; min-width: 0; padding: 2rem 3rem; }
        .content { max-width: 800px; margin: 0 auto; }
        .loading { display: flex; align-items: center; justify-content: center; height: 300px; color: var(--text-secondary); }
        .loading::after { content: ''; width: 32px; height: 32px; border: 3px solid var(--border-color); border-top-color: var(--neon-cyan); border-radius: 50%; animation: spin 0.8s linear infinite; margin-left: 1rem; }
        @keyframes spin { to { transform: rotate(360deg); } }
        .markdown h1 { font-size: 2.25rem; font-weight: 700; margin-bottom: 1.5rem; background: linear-gradient(135deg, var(--neon-cyan), var(--neon-magenta)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; line-height: 1.3; }
        .markdown h2 { font-size: 1.5rem; font-weight: 600; margin: 2.5rem 0 1rem; color: var(--neon-cyan); border-bottom: 1px solid var(--border-color); padding-bottom: 0.5rem; }
        .markdown h3 { font-size: 1.25rem; font-weight: 600; margin: 2rem 0 0.75rem; color: var(--neon-magenta); }
        .markdown h4 { font-size: 1.1rem; font-weight: 600; margin: 1.5rem 0 0.5rem; color: var(--text-primary); }
        .markdown p { margin-bottom: 1rem; color: var(--text-secondary); }
        .markdown a { color: var(--neon-cyan); text-decoration: none; }
        .markdown a:hover { text-decoration: underline; }
        .markdown strong { color: var(--text-primary); font-weight: 600; }
        .markdown ul, .markdown ol { margin: 1rem 0 1.5rem 1.5rem; color: var(--text-secondary); }
        .markdown li { margin-bottom: 0.5rem; }
        .markdown li::marker { color: var(--neon-cyan); }
        .markdown input[type="checkbox"] { appearance: none; width: 18px; height: 18px; border: 2px solid var(--border-color); border-radius: 4px; margin-right: 0.5rem; vertical-align: middle; position: relative; cursor: pointer; }
        .markdown input[type="checkbox"]:checked { background: var(--neon-cyan); border-color: var(--neon-cyan); }
        .markdown input[type="checkbox"]:checked::after { content: '✓'; position: absolute; color: var(--bg-dark); font-size: 12px; top: 50%; left: 50%; transform: translate(-50%, -50%); }
        .markdown code { font-family: 'JetBrains Mono', monospace; font-size: 0.875em; }
        .markdown :not(pre) > code { background: var(--bg-code); padding: 0.2em 0.4em; border-radius: 4px; color: var(--warning-yellow); }
        .markdown pre { background: var(--bg-code); border: 1px solid var(--border-color); border-radius: 8px; padding: 1.25rem; overflow-x: auto; margin: 1.5rem 0; }
        .markdown pre code { color: var(--text-primary); background: none; padding: 0; }
        .markdown blockquote { background: var(--bg-card); border-left: 4px solid var(--neon-cyan); border-radius: 0 8px 8px 0; padding: 1rem 1.25rem; margin: 1.5rem 0; }
        .markdown blockquote p { margin: 0; color: var(--text-secondary); }
        .markdown blockquote p:first-child { font-weight: 600; color: var(--neon-cyan); }
        .markdown img { max-width: 100%; border-radius: 8px; border: 1px solid var(--border-color); margin: 1.5rem 0; }
        .markdown table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; }
        .markdown th, .markdown td { padding: 0.75rem 1rem; border: 1px solid var(--border-color); text-align: left; }
        .markdown th { background: var(--bg-card); color: var(--text-primary); font-weight: 600; }
        .markdown td { color: var(--text-secondary); }
        .markdown tr:hover td { background: rgba(0,245,255,0.05); }
        .markdown hr { border: none; border-top: 1px solid var(--border-color); margin: 2.5rem 0; }
        .nav-footer { display: flex; justify-content: space-between; margin-top: 3rem; padding-top: 2rem; border-top: 1px solid var(--border-color); }
        .nav-footer-btn { display: inline-flex; align-items: center; gap: 0.5rem; padding: 0.75rem 1.5rem; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 8px; color: var(--text-primary); text-decoration: none; font-weight: 500; transition: all 0.2s ease; }
        .nav-footer-btn:hover { border-color: var(--neon-cyan); transform: translateY(-2px); }
        .nav-footer-btn.disabled { opacity: 0.4; pointer-events: none; }
        .brand-icon { font-size: 1.5rem; }
        @media (max-width: 900px) {
            .sidebar { display: none; }
            .main { padding: 1.5rem; }
            .header-title { display: none; }
        }