:root {
    --bg: #191127;
    --surface: #1f1232;
    --card: #23133a;
    --border: #3a1c63;
    --accent: #883CF0;
    --accent2: #af62c8;
    --accent3: #7c3aed;
    --text: #e8edf5;
    --muted: #d6d6d6;
    --glow: 0 0 30px #f000f02e;
    --font-display: 'Syne', sans-serif;
    --font-mono: 'Space Mono', monospace;
  }

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

  html { scroll-behavior: smooth; }

  body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-mono);
    overflow-x: hidden;
    cursor: none;
  }

  /* Custom Cursor */
  .cursor {
    width: 12px; height: 12px;
    background: var(--accent);
    border-radius: 50%;
    position: fixed;
    pointer-events: none;
    z-index: 9999;
    transition: transform 0.1s ease;
    mix-blend-mode: difference;
  }
  .cursor-ring {
    width: 36px; height: 36px;
    border: 1px solid var(--accent);
    border-radius: 50%;
    position: fixed;
    pointer-events: none;
    z-index: 9998;
    transition: all 0.15s ease;
    opacity: 0.5;
  }

  /* Grid Background */
  body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
      linear-gradient(rgba(183, 0, 255, 0.03) 1px, transparent 1px),
      linear-gradient(90deg, rgba(187, 0, 255, 0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
  }

  /* ── NAV ── */
  nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 48px;
    background: #180f26;
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
  }
  .nav-logo {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.1rem;
    letter-spacing: -0.02em;
    color: var(--accent);
  }
  .nav-logo span { color: var(--accent2); }
  .nav-links { display: flex; gap: 32px; }
  .nav-links a {
    text-decoration: none;
    color: var(--muted);
    font-size: 0.75rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    transition: color 0.2s;
  }
  .nav-links a:hover { color: var(--accent); }
  .nav-cta {
    background: transparent;
    border: 1px solid var(--accent);
    color: var(--accent);
    padding: 8px 20px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    cursor: none;
    transition: all 0.2s;
  }
  .nav-cta:hover { background: var(--accent); color: var(--bg); }

  /* ── HERO ── */
  .hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 120px 48px 80px;
    position: relative;
    z-index: 1;
  }

  .hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border: 1px solid var(--border);
    padding: 6px 16px;
    font-size: 0.7rem;
    letter-spacing: 0.15em;
    color: var(--accent);
    text-transform: uppercase;
    margin-bottom: 32px;
    animation: fadeUp 0.8s ease both;
  }
  .hero-badge::before {
    content: '';
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
    animation: pulse 1.5s infinite;
  }
  @keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.4; transform: scale(0.7); }
  }

  .hero h1 {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: clamp(3rem, 8vw, 7rem);
    line-height: 0.95;
    letter-spacing: -0.04em;
    margin-bottom: 24px;
    animation: fadeUp 0.8s ease 0.1s both;
  }
  .hero h1 .line1 { display: block; color: var(--text); }
  .hero h1 .line2 {
    display: block;
    background: linear-gradient(135deg, var(--accent), var(--accent3));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
  }
  .hero h1 .line3 { display: block; color: var(--accent2); }

  .hero-sub {
    font-size: 0.9rem;
    color: var(--muted);
    max-width: 480px;
    line-height: 1.8;
    margin-bottom: 48px;
    animation: fadeUp 0.8s ease 0.2s both;
  }

  .hero-actions {
    display: flex;
    gap: 16px;
    animation: fadeUp 0.8s ease 0.3s both;
  }
  .btn-primary {
    background: var(--accent);
    color: var(--bg);
    border: none;
    padding: 14px 32px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    cursor: none;
    transition: all 0.2s;
    position: relative;
    overflow: hidden;
  }
  .btn-primary::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(255,255,255,0.2);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }
  .btn-primary:hover::after { transform: translateX(0); }
  .btn-secondary {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
    padding: 14px 32px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    letter-spacing: 0.05em;
    cursor: none;
    transition: all 0.2s;
  }
  .btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

  /* Floating Nodes */
  .nodes-container {
    position: absolute;
    inset: 0;
    overflow: hidden;
    pointer-events: none;
  }
  .node {
    position: absolute;
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
    opacity: 0;
    animation: floatNode linear infinite;
  }
  @keyframes floatNode {
    0% { opacity: 0; transform: translateY(100vh) scale(0); }
    10% { opacity: 0.6; }
    90% { opacity: 0.6; }
    100% { opacity: 0; transform: translateY(-100px) scale(1); }
  }

  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
  }

  /* ── STATS BAR ── */
  .stats-bar {
    position: relative;
    z-index: 1;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    background: var(--surface);
  }
  .stat-item {
    padding: 32px 48px;
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    gap: 4px;
  }
  .stat-item:last-child { border-right: none; }
  .stat-num {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--accent);
    line-height: 1;
  }
  .stat-label { font-size: 0.7rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.1em; }

  /* ── SECTION COMMON ── */
  section { position: relative; z-index: 1; }
  .section-label {
    font-size: 0.65rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 12px;
  }
  .section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 3.5rem);
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.05;
  }

  /* ── WHAT IS MCP ── */
  .what-is {
    padding: 100px 48px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
  }
  .what-is-visual {
    position: relative;
    height: 420px;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  /* USB-C Diagram */
  .usb-diagram {
    width: 100%;
    height: 100%;
    position: relative;
  }
  .usb-center {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    width: 100px; height: 100px;
    border: 2px solid var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 0.9rem;
    color: var(--accent);
    background: var(--bg);
    z-index: 2;
    box-shadow: var(--glow);
  }
  .usb-ring {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    border: 1px solid rgba(153, 0, 255, 0.2);
    border-radius: 50%;
    animation: spin linear infinite;
  }
  .usb-ring-1 { width: 160px; height: 160px; animation-duration: 20s; }
  .usb-ring-2 { width: 240px; height: 240px; animation-duration: 30s; animation-direction: reverse; }
  .usb-ring-3 { width: 320px; height: 320px; animation-duration: 40s; border-style: dashed; }
  @keyframes spin { from { transform: translate(-50%, -50%) rotate(0deg); } to { transform: translate(-50%, -50%) rotate(360deg); } }

  .orbit-dot {
    position: absolute;
    width: 10px; height: 10px;
    border-radius: 50%;
    background: var(--accent2);
    top: 50%; left: 50%;
    transform-origin: 0 0;
  }
  .orbit-label {
    position: absolute;
    font-size: 0.65rem;
    color: var(--muted);
    white-space: nowrap;
  }

  .connector-item {
    position: absolute;
    width: 36px; height: 36px;
    border: 1px solid var(--border);
    background: var(--card);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
  }

  .what-is-content p {
    color: var(--muted);
    line-height: 1.9;
    font-size: 0.85rem;
    margin-bottom: 16px;
  }
  .what-is-content strong { color: var(--accent); font-weight: 700; }

  /* ── HOW IT WORKS ── */
  .how-it-works {
    padding: 100px 48px;
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
  }
  .how-header {
    max-width: 1200px;
    margin: 0 auto 64px;
  }

  .steps-flow {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0;
    position: relative;
  }
  .steps-flow::before {
    content: '';
    position: absolute;
    top: 40px; left: 10%; right: 10%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent), var(--accent3), var(--accent2), transparent);
  }

  .step-card {
    padding: 24px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 16px;
    position: relative;
  }
  .step-num {
    width: 80px; height: 80px;
    border: 1px solid var(--border);
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--accent);
    position: relative;
    z-index: 1;
    transition: all 0.3s;
  }
  .step-card:hover .step-num {
    background: var(--accent);
    color: var(--bg);
    box-shadow: var(--glow);
  }
  .step-title {
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text);
  }
  .step-desc { font-size: 0.72rem; color: var(--muted); line-height: 1.7; }

  /* ── INTERACTIVE DEMO ── */
  .demo-section {
    padding: 100px 48px;
    max-width: 1200px;
    margin: 0 auto;
  }
  .demo-header { margin-bottom: 48px; }
  .demo-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2px;
    background: var(--border);
    border: 1px solid var(--border);
  }

  .demo-panel {
    background: var(--bg);
    padding: 32px;
  }
  .demo-panel-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 24px;
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--muted);
  }
  .demo-panel-header .dot {
    width: 8px; height: 8px; border-radius: 50%;
  }
  .demo-panel-header .dot-r { background: #ff5f57; }
  .demo-panel-header .dot-y { background: #ffbd2e; }
  .demo-panel-header .dot-g { background: #28ca41; }

  /* Tool selector */
  .tool-tabs {
    display: flex;
    gap: 2px;
    margin-bottom: 24px;
    background: var(--surface);
    padding: 4px;
  }
  .tool-tab {
    flex: 1;
    padding: 8px;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    background: transparent;
    border: none;
    color: var(--muted);
    cursor: none;
    transition: all 0.2s;
    text-align: center;
  }
  .tool-tab.active {
    background: var(--accent);
    color: var(--bg);
    font-weight: 700;
  }
  .tool-tab:hover:not(.active) { color: var(--text); background: var(--border); }

  .tool-content { display: none; }
  .tool-content.active { display: block; }

  .code-block {
    background: var(--surface);
    padding: 20px;
    font-size: 0.72rem;
    line-height: 1.8;
    overflow-x: auto;
    border-left: 2px solid var(--accent3);
    white-space: pre;
  }
  .code-block .kw { color: #c792ea; }
  .code-block .fn { color: #82aaff; }
  .code-block .str { color: #c3e88d; }
  .code-block .cm { color: #546e7a; font-style: italic; }
  .code-block .num { color: #f78c6c; }

  /* Output panel */
  .output-area {
    min-height: 280px;
    background: var(--surface);
    padding: 20px;
    font-size: 0.75rem;
    line-height: 1.8;
  }
  .output-line { margin-bottom: 4px; }
  .output-line .ts { color: var(--muted); margin-right: 8px; }
  .output-line.success .msg { color: #28ca41; }
  .output-line.info .msg { color: var(--accent); }
  .output-line.warn .msg { color: #ffbd2e; }
  .output-line.error .msg { color: #ff5f57; }

  .run-btn {
    width: 100%;
    margin-top: 16px;
    padding: 12px;
    background: var(--accent3);
    color: white;
    border: none;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    cursor: none;
    transition: all 0.2s;
  }
  .run-btn:hover { background: #9333ea; box-shadow: 0 0 20px rgba(124,58,237,0.4); }

  /* ── USE CASES ── */
  .use-cases {
    padding: 100px 48px;
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
  }
  .use-cases-inner {
    max-width: 1200px;
    margin: 0 auto;
  }
  .use-cases-header { margin-bottom: 64px; }
  .cases-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2px;
    background: var(--border);
  }
  .case-card {
    background: var(--bg);
    padding: 40px 32px;
    transition: all 0.3s;
    cursor: none;
    position: relative;
    overflow: hidden;
  }
  .case-card::after {
    content: '';
    position: absolute;
    bottom: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--accent3));
    transform: scaleX(0);
    transition: transform 0.3s ease;
  }
  .case-card:hover::after { transform: scaleX(1); }
  .case-card:hover { background: var(--card); }

  .case-icon {
    font-size: 2rem;
    margin-bottom: 20px;
    display: block;
  }
  .case-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--text);
  }
  .case-desc {
    font-size: 0.75rem;
    color: var(--muted);
    line-height: 1.8;
  }
  .case-tag {
    display: inline-block;
    margin-top: 16px;
    padding: 4px 10px;
    font-size: 0.65rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    border: 1px solid var(--border);
    color: var(--accent);
  }

  /* ── LEARNING PATH ── */
  .learning {
    padding: 100px 48px;
    max-width: 1200px;
    margin: 0 auto;
  }
  .learning-header { margin-bottom: 64px; }
  .path-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2px;
    background: var(--border);
  }
  .path-item {
    background: var(--bg);
    padding: 28px 32px;
    display: grid;
    grid-template-columns: 64px 1fr auto;
    gap: 24px;
    align-items: center;
    cursor: none;
    transition: background 0.2s;
  }
  .path-item:hover { background: var(--card); }
  .path-num {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 800;
    color: var(--border);
    line-height: 1;
  }
  .path-item:hover .path-num { color: var(--accent); }

  .path-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1rem;
    margin-bottom: 4px;
  }
  .path-desc { font-size: 0.75rem; color: var(--muted); }
  .path-level {
    font-size: 0.65rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding: 6px 14px;
    border: 1px solid;
  }
  .path-level.beginner { color: #28ca41; border-color: #28ca41; }
  .path-level.intermediate { color: #ffbd2e; border-color: #ffbd2e; }
  .path-level.advanced { color: var(--accent2); border-color: var(--accent2); }
  .path-level.expert { color: var(--accent); border-color: var(--accent); }

  /* ── QUIZ SECTION ── */
  .quiz-section {
    padding: 100px 48px;
    background: var(--surface);
    border-top: 1px solid var(--border);
  }
  .quiz-inner {
    max-width: 720px;
    margin: 0 auto;
  }
  .quiz-header { margin-bottom: 48px; }
  .quiz-card {
    border: 1px solid var(--border);
    padding: 40px;
    background: var(--bg);
  }
  .quiz-progress {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 32px;
  }
  .quiz-progress-bar {
    flex: 1;
    height: 2px;
    background: var(--border);
  }
  .quiz-progress-fill {
    height: 100%;
    background: var(--accent);
    transition: width 0.4s ease;
  }
  .quiz-counter { font-size: 0.7rem; color: var(--muted); white-space: nowrap; }

  .quiz-q {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 28px;
    line-height: 1.4;
    color: var(--text);
  }
  .quiz-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 24px;
  }
  .quiz-opt {
    padding: 14px 18px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--muted);
    font-family: var(--font-mono);
    font-size: 0.8rem;
    text-align: left;
    cursor: none;
    transition: all 0.2s;
  }
  .quiz-opt:hover:not(:disabled) { border-color: var(--accent); color: var(--text); }
  .quiz-opt.correct { border-color: #28ca41; color: #28ca41; background: #28ca411a; }
  .quiz-opt.wrong { border-color: #ff5f57; color: #ff5f57; background: #ff5f571a; }

  .quiz-feedback {
    font-size: 0.8rem;
    min-height: 24px;
    color: var(--muted);
    margin-bottom: 20px;
  }
  .quiz-feedback.correct-msg { color: #28ca41; }
  .quiz-feedback.wrong-msg { color: #ff5f57; }

  .quiz-result {
    text-align: center;
    padding: 40px;
    display: none;
  }
  .quiz-result.show { display: block; }
  .quiz-score {
    font-family: var(--font-display);
    font-size: 4rem;
    font-weight: 800;
    color: var(--accent);
    line-height: 1;
    margin-bottom: 12px;
  }
  .quiz-result-msg { color: var(--muted); font-size: 0.85rem; margin-bottom: 24px; }

  /* ── GLOSSARY ── */
  .glossary {
    padding: 100px 48px;
    max-width: 1200px;
    margin: 0 auto;
  }
  .glossary-header { margin-bottom: 48px; }
  .glossary-search {
    width: 100%;
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 14px 20px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text);
    margin-bottom: 24px;
    outline: none;
    transition: border-color 0.2s;
  }
  .glossary-search:focus { border-color: var(--accent); }
  .glossary-search::placeholder { color: var(--muted); }
  .terms-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2px;
    background: var(--border);
  }
  .term-card {
    background: var(--bg);
    padding: 24px 28px;
    transition: background 0.2s;
  }
  .term-card:hover { background: var(--card); }
  .term-name {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--accent);
    margin-bottom: 8px;
  }
  .term-def {
    font-size: 0.75rem;
    color: var(--muted);
    line-height: 1.7;
  }
  .term-card.hidden { display: none; }

  /* ── FOOTER ── */
  footer {
    position: relative;
    z-index: 1;
    border-top: 1px solid var(--border);
    padding: 60px 48px;
    background: var(--surface);
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 40px;
  }
  .footer-brand {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--accent);
  }
  .footer-brand span { color: var(--accent2); }
  .footer-tagline {
    font-size: 0.75rem;
    color: var(--muted);
    margin-top: 6px;
  }
  .footer-right {
    text-align: right;
    font-size: 0.7rem;
    color: var(--muted);
    line-height: 1.8;
  }

  /* ── SCROLL ANIMATIONS ── */
  .reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
  }
  .reveal.visible { opacity: 1; transform: translateY(0); }

  /* ── TOOLTIP ── */
  .tooltip-wrapper { position: relative; display: inline-block; }
  .tooltip-trigger { border-bottom: 1px dotted var(--accent); cursor: none; color: var(--accent); }
  .tooltip-box {
    position: absolute;
    bottom: 130%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--card);
    border: 1px solid var(--border);
    padding: 10px 14px;
    font-size: 0.7rem;
    color: var(--text);
    white-space: nowrap;
    z-index: 10;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
    line-height: 1.6;
  }
  .tooltip-wrapper:hover .tooltip-box { opacity: 1; }

  @media (max-width: 900px) {
    nav { padding: 16px 24px; }
    .nav-links { display: none; }
    .what-is, .demo-grid, .cases-grid { grid-template-columns: 1fr; }
    .steps-flow { grid-template-columns: 1fr; }
    .steps-flow::before { display: none; }
    .stats-bar { grid-template-columns: 1fr 1fr; }
    .path-item { grid-template-columns: 1fr; }
    .terms-grid { grid-template-columns: 1fr; }
    footer { grid-template-columns: 1fr; }
    .footer-right { text-align: left; }
    .hero { padding: 100px 24px 60px; }
  }