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

    :root {
      --bg-primary: #0a0e1a;
      --bg-secondary: #111827;
      --bg-card: #1a1f35;
      --text-primary: #e5e7eb;
      --text-secondary: #9ca3af;
      --accent: #3b82f6;
      --accent-hover: #2563eb;
      --accent-glow: rgba(59, 130, 246, 0.3);
      --border: rgba(255, 255, 255, 0.1);
      --shadow: rgba(0, 0, 0, 0.3);
      --purple: #8b5cf6;
      --purple-glow: rgba(139, 92, 246, 0.3);
    }

    body {
      font-family: 'Inter', sans-serif;
      background: var(--bg-primary);
      color: var(--text-primary);
      line-height: 1.6;
      overflow-x: hidden;
    }

    /* ===== HEADER ===== */
    header {
      position: fixed;
      top: 0;
      width: 100%;
      background: rgba(10, 14, 26, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border);
      z-index: 1000;
    }

    nav {
      max-width: 1200px;
      margin: 0 auto;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 1.2rem 2rem;
    }

    .logo {
      font-size: 1.5rem;
      font-weight: 700;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      text-decoration: none;
    }

    .back-btn {
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
      padding: 0.6rem 1.25rem;
      border: 2px solid var(--border);
      border-radius: 8px;
      color: var(--text-secondary);
      text-decoration: none;
      font-weight: 500;
      transition: all 0.3s;
      font-size: 0.9rem;
    }

    .back-btn:hover {
      border-color: var(--accent);
      color: var(--accent);
      background: var(--accent-glow);
    }

    /* ===== HERO ===== */
    .hero {
      min-height: 60vh;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      text-align: center;
      padding: 8rem 2rem 4rem;
      position: relative;
      overflow: hidden;
    }

    .hero::before {
      content: '';
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 700px;
      height: 700px;
      background: radial-gradient(circle, var(--accent-glow), transparent 65%);
      opacity: 0.3;
      animation: pulse 4s ease-in-out infinite;
    }

    @keyframes pulse {
      0%, 100% { transform: translate(-50%, -50%) scale(1); opacity: 0.3; }
      50% { transform: translate(-50%, -50%) scale(1.1); opacity: 0.5; }
    }

    .hero-badge {
      display: inline-block;
      padding: 0.4rem 1.2rem;
      background: var(--accent-glow);
      color: var(--accent);
      border: 1px solid rgba(59, 130, 246, 0.4);
      border-radius: 30px;
      font-size: 0.85rem;
      font-weight: 600;
      letter-spacing: 0.1em;
      margin-bottom: 1.5rem;
      position: relative;
      z-index: 1;
    }

    .hero h1 {
      font-size: clamp(2.5rem, 5vw, 4rem);
      font-weight: 700;
      margin-bottom: 1.25rem;
      background: linear-gradient(135deg, var(--text-primary), var(--accent));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      position: relative;
      z-index: 1;
    }

    .hero-sub {
      font-size: 1.1rem;
      color: var(--text-secondary);
      position: relative;
      z-index: 1;
    }

    /* ===== SECTIONS ===== */
    .section {
      max-width: 1100px;
      margin: 0 auto;
      padding: 4rem 2rem;
    }

    .section-title {
      font-size: 2rem;
      font-weight: 700;
      margin-bottom: 2.5rem;
      position: relative;
      padding-bottom: 1rem;
      text-align: center;
    }

    .section-title::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 70px;
      height: 4px;
      background: linear-gradient(90deg, var(--accent), var(--purple));
      border-radius: 2px;
    }

    /* ===== PRESENTATION CARD ===== */
    .presentation-card {
      background: var(--bg-card);
      border-radius: 20px;
      border: 1px solid var(--border);
      padding: 2.5rem;
      box-shadow: 0 10px 40px var(--shadow);
      position: relative;
      overflow: hidden;
    }

    .presentation-card::before {
      content: '';
      position: absolute;
      top: 0; left: 0; right: 0;
      height: 4px;
      background: linear-gradient(90deg, var(--accent), var(--purple));
    }

    .presentation-card p {
      color: var(--text-secondary);
      font-size: 1.05rem;
      line-height: 1.9;
      margin-bottom: 1.25rem;
    }

    .presentation-card p:last-child {
      margin-bottom: 0;
    }

    .presentation-card strong {
      color: var(--accent);
    }

    /* ===== TABLEAU IMAGE ===== */
    .tableau-wrapper {
      background: var(--bg-card);
      border-radius: 20px;
      border: 1px solid var(--border);
      overflow: hidden;
      box-shadow: 0 10px 40px var(--shadow);
    }

    .tableau-header {
      padding: 1.5rem 2rem;
      border-bottom: 1px solid var(--border);
      display: flex;
      align-items: center;
      gap: 1rem;
    }

    .tableau-header-icon {
      width: 40px;
      height: 40px;
      background: var(--accent-glow);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.2rem;
    }

    .tableau-header h3 {
      font-size: 1.2rem;
      font-weight: 600;
    }

    .tableau-img {
      width: 100%;
      display: block;
      transition: transform 0.4s ease;
    }

    .tableau-wrapper:hover .tableau-img {
      transform: scale(1.01);
    }

    /* ===== STAGES BUTTONS ===== */
    .stages-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
      margin-bottom: 3rem;
    }

    .stage-btn {
      background: var(--bg-card);
      border: 2px solid var(--border);
      border-radius: 16px;
      padding: 2rem;
      cursor: pointer;
      transition: all 0.3s;
      text-align: left;
      position: relative;
      overflow: hidden;
    }

    .stage-btn::before {
      content: '';
      position: absolute;
      top: 0; left: 0; right: 0;
      height: 3px;
      background: linear-gradient(90deg, var(--accent), var(--purple));
      transform: scaleX(0);
      transition: transform 0.3s ease;
    }

    .stage-btn:hover::before,
    .stage-btn.active::before {
      transform: scaleX(1);
    }

    .stage-btn:hover,
    .stage-btn.active {
      border-color: var(--accent);
      box-shadow: 0 8px 30px var(--accent-glow);
      transform: translateY(-4px);
    }

    .stage-btn.active {
      background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.05));
    }

    .stage-number {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 40px;
      height: 40px;
      background: var(--accent-glow);
      color: var(--accent);
      border-radius: 10px;
      font-weight: 700;
      font-size: 1.2rem;
      margin-bottom: 1rem;
    }

    .stage-btn h3 {
      font-size: 1.2rem;
      font-weight: 600;
      margin-bottom: 0.5rem;
      color: var(--text-primary);
    }

    .stage-btn p {
      color: var(--text-secondary);
      font-size: 0.9rem;
    }

    .stage-arrow {
      position: absolute;
      bottom: 1.25rem;
      right: 1.5rem;
      color: var(--accent);
      font-size: 1.2rem;
      transition: transform 0.3s;
    }

    .stage-btn.active .stage-arrow {
      transform: rotate(90deg);
    }

    /* ===== STAGE DETAIL PANEL ===== */
    .stage-detail {
      display: none;
      background: var(--bg-card);
      border-radius: 20px;
      border: 1px solid var(--border);
      overflow: hidden;
      box-shadow: 0 10px 40px var(--shadow);
      animation: slideDown 0.4s ease;
    }

    .stage-detail.active {
      display: block;
    }

    @keyframes slideDown {
      from {
        opacity: 0;
        transform: translateY(-20px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    .stage-detail-header {
      padding: 2rem;
      border-bottom: 1px solid var(--border);
      background: linear-gradient(135deg, rgba(59, 130, 246, 0.08), rgba(139, 92, 246, 0.04));
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 1rem;
    }

    .stage-detail-header h3 {
      font-size: 1.5rem;
      font-weight: 700;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .stage-year-badge {
      padding: 0.4rem 1rem;
      background: var(--accent-glow);
      color: var(--accent);
      border-radius: 20px;
      font-size: 0.85rem;
      font-weight: 600;
      border: 1px solid rgba(59, 130, 246, 0.3);
    }

    .stage-detail-body {
      padding: 2rem;
    }

    .detail-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
      margin-bottom: 2rem;
    }

    .detail-item {
      background: var(--bg-secondary);
      padding: 1.25rem;
      border-radius: 12px;
      border: 1px solid var(--border);
    }

    .detail-item-label {
      font-size: 0.8rem;
      color: var(--accent);
      font-weight: 600;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      margin-bottom: 0.4rem;
    }

    .detail-item-value {
      color: var(--text-primary);
      font-weight: 500;
      font-size: 0.95rem;
    }

    .detail-description {
      color: var(--text-secondary);
      line-height: 1.8;
      margin-bottom: 2rem;
      font-size: 1rem;
    }

    .detail-description strong {
      color: var(--text-primary);
    }

    .skills-list {
      display: flex;
      flex-wrap: wrap;
      gap: 0.75rem;
      margin-bottom: 2rem;
    }

    .skill-tag {
      padding: 0.4rem 1rem;
      background: rgba(59, 130, 246, 0.1);
      color: var(--accent);
      border-radius: 20px;
      font-size: 0.85rem;
      font-weight: 500;
      border: 1px solid rgba(59, 130, 246, 0.2);
    }

    .tasks-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 0.75rem;
      margin-bottom: 2rem;
    }

    .tasks-list li {
      display: flex;
      align-items: flex-start;
      gap: 0.75rem;
      color: var(--text-secondary);
      font-size: 0.95rem;
      line-height: 1.6;
    }

    .tasks-list li::before {
      content: '▹';
      color: var(--accent);
      font-size: 1rem;
      flex-shrink: 0;
      margin-top: 1px;
    }

    .section-sub-title {
      font-size: 1rem;
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 1rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .section-sub-title::before {
      content: '';
      display: inline-block;
      width: 4px;
      height: 1rem;
      background: var(--accent);
      border-radius: 2px;
    }

    .divider {
      border: none;
      border-top: 1px solid var(--border);
      margin: 2rem 0;
    }

    /* ===== DOWNLOAD BUTTON ===== */
    .download-btn {
      display: inline-flex;
      align-items: center;
      gap: 0.75rem;
      padding: 1rem 2rem;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      color: white;
      border-radius: 12px;
      text-decoration: none;
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.3s;
      box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
      border: none;
    }

    .download-btn:hover {
      transform: translateY(-3px);
      box-shadow: 0 8px 25px rgba(59, 130, 246, 0.4);
    }

    .btn-icon {
      font-size: 1.3rem;
    }

    /* ===== FOOTER ===== */
    footer {
      text-align: center;
      padding: 3rem 2rem;
      border-top: 1px solid var(--border);
      color: var(--text-secondary);
      font-size: 0.9rem;
    }

    /* ===== RESPONSIVE ===== */
    @media (max-width: 768px) {
      .stages-grid { grid-template-columns: 1fr; }
      .detail-grid { grid-template-columns: 1fr; }
      .stage-detail-header { flex-direction: column; align-items: flex-start; }
      .hero h1 { font-size: 2rem; }
    }