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

    html, body {
      font-family: 'Inter', sans-serif;
      height: 100%; width: 100%;
      overflow: hidden;
    }

    nav {
      position: fixed;
      top: 0; left: 0; right: 0;
      z-index: 200;
      display: flex;
      align-items: center;
      justify-content: flex-start;
      padding: 1.4rem 2.5rem;
    }
    nav .logo {
      font-size: 1.2rem;
      font-weight: 500;
      letter-spacing: 0.12em;
      text-transform: uppercase;
    }
    nav.dark .logo {
      color: #171a20 !important;
      text-shadow: none !important;
    }
    nav .logo-white {
      color: #fff;
      text-shadow: 0 1px 8px rgba(0,0,0,0.4);
    }
    nav .logo-dark {
      color: #000;
      text-shadow: none;
    }

    #scroll-container {
      height: 100vh;
      overflow-y: scroll;
      scroll-snap-type: y mandatory;
      scroll-behavior: smooth;
      -webkit-overflow-scrolling: touch;
    }
    #scroll-container::-webkit-scrollbar { display: none; }
    #scroll-container { -ms-overflow-style: none; scrollbar-width: none; }

    section {
      height: 100vh;
      scroll-snap-align: start;
      scroll-snap-stop: always;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* HERO */
    #s1 {
      background: url('hero-bg2.jpg') center center / cover no-repeat;
      background-color: #1a1a1a;
    }

    .hero-heading {
      position: absolute; left: 50%; top: 18%;
      transform: translateX(-50%);
      text-align: center; white-space: nowrap;
      font-family: 'DM Serif Display', serif;
      font-size: clamp(1.8rem, 3.5vw, 2.8rem);
      font-weight: 400; letter-spacing: 0.01em;
      color: #fff; text-shadow: 0 2px 16px rgba(0,0,0,0.6);
      z-index: 2;
      animation: fadeUp 1.2s ease-out both;
    }

    .hero-tagline {
      position: absolute; left: 50%; top: 27%;
      transform: translateX(-50%);
      text-align: center; white-space: nowrap;
      font-size: clamp(1rem, 1.8vw, 1.3rem);
      font-weight: 300; letter-spacing: 0.06em;
      color: rgba(255,255,255,0.75); text-shadow: 0 1px 10px rgba(0,0,0,0.5);
      z-index: 2;
      animation: fadeUp 1.2s 0.15s ease-out both;
    }
    /* FIXED BUTTON BAR */

    /* Box expansion animation - top of s3 */
    .box-anim-wrap {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      padding: 3.5rem 0 0 0;
      z-index: 3;
    }
    .box-anim-svg {
      width: 100%;
      height: auto;
      max-height: 85px;
    }
    .box-frame {
      opacity: 0;
      transition: opacity 0.6s ease;
    }
    .box-frame.active {
      opacity: 1;
    }

    #btnBar {
      position: fixed;
      top: 90%;
      left: 50%;
      transform: translate(-50%, -50%);
      z-index: 150;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: top 0.7s cubic-bezier(0.4,0,0.2,1), left 0.7s cubic-bezier(0.4,0,0.2,1), transform 0.7s cubic-bezier(0.4,0,0.2,1);
    }
    #btnDemo {
      transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.3s ease, color 0.3s ease;
    }
    .btn {
      display: inline-block; padding: 0.75rem 2.6rem; border-radius: 4px;
      font-size: 0.88rem; font-weight: 500; letter-spacing: 0.02em;
      text-decoration: none; cursor: pointer; border: none;
      transition: transform 0.25s ease, box-shadow 0.25s ease;
      min-width: 200px; text-align: center;
    }
    .btn:hover { transform: scale(1.06); box-shadow: 0 4px 20px rgba(0,0,0,0.3); }
    .btn-primary { background: #171a20; color: #fff; }
    .btn-secondary {
      background: #fff; color: #171a20;
    }
    .scroll-arrow {
      position: absolute; bottom: 0.4rem; left: 50%;
      transform: translateX(-50%); z-index: 2;
      animation: blink 1.4s ease-in-out infinite;
    }
    .scroll-arrow svg { width: 36px; height: 36px; }
    @keyframes blink { 0%,100%{opacity:1;} 50%{opacity:0;} }
    @keyframes fadeUp {
      from { opacity: 0; transform: translateX(-50%) translateY(20px); }
      to   { opacity: 1; transform: translateX(-50%) translateY(0); }
    }

    /* SECTION 2 */
    #s2 {
      background: #e8e8e8;
      color: #222;
      overflow: hidden;
      position: relative;
      align-items: stretch;
      justify-content: stretch;
    }
    #s2::before {
      content: '';
      position: absolute; inset: -40%;
      width: 180%; height: 180%;
      background:
        radial-gradient(ellipse 600px 400px at 20% 50%, rgba(0,0,0,0.04), transparent),
        radial-gradient(ellipse 500px 500px at 80% 30%, rgba(0,0,0,0.03), transparent),
        radial-gradient(ellipse 700px 300px at 50% 80%, rgba(0,0,0,0.025), transparent);
      animation: smokeDrift 18s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    #s2::after {
      content: '';
      position: absolute; inset: -30%;
      width: 160%; height: 160%;
      background:
        radial-gradient(ellipse 400px 600px at 70% 60%, rgba(0,0,0,0.03), transparent),
        radial-gradient(ellipse 500px 350px at 30% 20%, rgba(0,0,0,0.02), transparent);
      animation: smokeDrift2 22s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    @keyframes smokeDrift {
      0%   { transform: translate(0,0) rotate(0deg); opacity: 0.7; }
      50%  { transform: translate(30px,-20px) rotate(2deg); opacity: 1; }
      100% { transform: translate(-20px,15px) rotate(-1deg); opacity: 0.8; }
    }
    @keyframes smokeDrift2 {
      0%   { transform: translate(0,0) rotate(0deg); opacity: 0.6; }
      50%  { transform: translate(-25px,25px) rotate(-2deg); opacity: 1; }
      100% { transform: translate(15px,-10px) rotate(1.5deg); opacity: 0.7; }
    }

    /* S2 Layout */
    .s2-layout {
      width: 100%; height: 100%;
      position: relative; z-index: 1;
      display: flex;
      flex-direction: column;
    }

    /* Header — left side, vertically centered in upper half */
    .s2-header {
      position: absolute;
      top: 50%;
      left: 4rem;
      transform: translateY(-70%);
      z-index: 2;
      max-width: 520px;
    }
    .s2-header h2 {
      font-family: 'DM Serif Display', serif;
      font-size: clamp(2.4rem, 4vw, 3.4rem);
      font-weight: 400;
      font-style: italic;
      letter-spacing: -0.01em;
      line-height: 1.18;
      margin: 0;
      color: #171a20;
      text-shadow: 0 2px 8px rgba(0,0,0,0.08);
    }
    .s2-header .s2-sub {
      font-family: 'Inter', sans-serif;
      font-size: clamp(1.3rem, 2.2vw, 1.7rem);
      font-weight: 400;
      letter-spacing: 0.01em;
      color: #555;
      margin-top: 1.2rem;
      line-height: 1.4;
      display: block;
    }

    /* Body — full section, sidebar right, panel area center-right */
    .s2-body {
      position: absolute;
      inset: 0;
      display: flex;
      align-items: stretch;
    }

    /* Expand area — center-right large zone */
    .s2-expand-area {
      flex: 1;
      position: relative;
      min-width: 0;
    }
    .s2-panel {
      position: absolute;
      top: 8%;
      right: 185px;
      width: 48vw;
      max-width: 680px;
      height: 72%;
      min-height: 280px;
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.08);
      border-radius: 18px;
      padding: 2.5rem 3rem;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
      transform: scale(0);
      transform-origin: right center;
      opacity: 0;
      transition:
        transform 0.5s cubic-bezier(0.4, 0, 0.2, 1),
        opacity 0.35s cubic-bezier(0.4, 0, 0.2, 1),
        transform-origin 0s;
      pointer-events: none;
      z-index: 3;
      display: flex;
      flex-direction: column;
      justify-content: center;
      overflow: hidden;
    }
    .s2-panel.open {
      transform: scale(1);
      opacity: 1;
      pointer-events: auto;
    }
    .s2-panel-inner {
      opacity: 0;
      transform: translateY(12px);
      transition: opacity 0.3s 0.18s ease, transform 0.3s 0.18s ease;
      overflow-y: auto;
      padding-right: 0.5rem;
      display: flex;
      flex-direction: column;
      gap: 0;
    }
    .s2-panel-inner::-webkit-scrollbar { width: 3px; }
    .s2-panel-inner::-webkit-scrollbar-track { background: transparent; }
    .s2-panel-inner::-webkit-scrollbar-thumb { background: rgba(0,0,0,0.15); border-radius: 2px; }
    .s2-panel.open .s2-panel-inner {
      opacity: 1;
      transform: translateY(0);
    }
    .s2-exp-close {
      position: absolute;
      top: 1.2rem; right: 1.2rem;
      width: 32px; height: 32px;
      border-radius: 50%;
      border: 1px solid rgba(0,0,0,0.12);
      background: rgba(0,0,0,0.03);
      color: rgba(0,0,0,0.4);
      font-size: 0.9rem;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.3s ease;
      font-family: 'Inter', sans-serif;
      line-height: 1;
      z-index: 2;
    }
    .s2-exp-close:hover {
      background: rgba(0,0,0,0.06);
      border-color: rgba(0,0,0,0.25);
      color: #222;
    }
    .s2-exp-icon {
      width: 40px; height: 40px;
      opacity: 0.7;
      margin-bottom: 1.2rem;
    }
    .s2-exp-icon svg { width: 100%; height: 100%; }
    .s2-exp-title {
      font-family: 'DM Serif Display', serif;
      font-size: 1.4rem;
      font-weight: 400;
      font-style: italic;
      letter-spacing: -0.01em;
      margin-bottom: 1.2rem;
      color: #171a20;
      text-shadow: 0 1px 4px rgba(0,0,0,0.06);
    }
    .s2-exp-divider {
      width: 32px;
      height: 1px;
      background: rgba(0,0,0,0.12);
      margin-bottom: 1.4rem;
    }
    .s2-exp-text {
      font-size: 0.88rem;
      line-height: 1.85;
      color: #666;
    }
    .s2-exp-text p {
      margin: 0 0 1rem 0;
    }
    .s2-exp-text p:last-child {
      margin-bottom: 0;
    }

    /* Sidebar — right column */
    .s2-sidebar {
      width: 170px;
      flex-shrink: 0;
      display: flex;
      flex-direction: column;
      gap: 0.8rem;
      padding: 3rem 1.5rem 3rem 0;
      justify-content: center;
      z-index: 4;
    }
    .s2-card {
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-radius: 14px;
      padding: 0.9rem 0.7rem;
      cursor: pointer;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 120px;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
      transition: all 0.4s cubic-bezier(0.4,0,0.2,1);
      position: relative;
    }
    .s2-card:hover {
      background: #fff;
      border-color: rgba(0,0,0,0.12);
      transform: translateX(-4px) translateY(-2px);
      box-shadow:
        0 2px 4px rgba(0,0,0,0.08),
        0 6px 12px rgba(0,0,0,0.08),
        0 12px 24px rgba(0,0,0,0.10),
        0 24px 48px rgba(0,0,0,0.12),
        0 40px 80px rgba(0,0,0,0.14);
    }
    .s2-card.active-card {
      border-color: rgba(0,0,0,0.22);
      background: #f0f0f0;
      transform: translateX(-6px);
    }
    .s2-card-icon {
      width: 52px; height: 52px;
      opacity: 0.7;
      margin-bottom: 0.4rem;
      transition: opacity 0.3s ease;
    }
    .s2-card-icon svg { width: 100%; height: 100%; }
    .s2-card:hover .s2-card-icon,
    .s2-card.active-card .s2-card-icon { opacity: 0.95; }
    .s2-card-title {
      font-size: 0.68rem;
      font-weight: 500;
      text-align: center;
      letter-spacing: 0.02em;
      color: #555;
    }
    .s2-card.active-card .s2-card-title { color: #171a20; }

    @media (max-width:800px) {
      .s2-body { flex-direction: column-reverse; }
      .s2-header { position: relative; top: auto; left: auto; padding: 3rem 2rem 0 2rem; }
      .s2-sidebar { width: 100%; flex-direction: row; padding: 1rem 2rem; overflow-x: auto; z-index: 4; }
      .s2-card { min-height: 80px; min-width: 110px; }
      .s2-panel { position: relative; top: auto; right: auto; width: 100%; height: auto; }
    }
    /* FIXED FLOATING CTA */

    /* SECTION 3: Economics */
    #s3 {
      background: #e8e8e8;
      flex-direction: row;
      align-items: stretch;
      justify-content: stretch;
      color: #222;
      overflow: hidden;
      position: relative;
    }
    #s3::before {
      content: '';
      position: absolute; inset: -40%;
      width: 180%; height: 180%;
      background:
        radial-gradient(ellipse 500px 500px at 75% 40%, rgba(0,0,0,0.035), transparent),
        radial-gradient(ellipse 600px 350px at 25% 70%, rgba(0,0,0,0.025), transparent);
      animation: smokeDrift 20s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    #s3::after {
      content: '';
      position: absolute; inset: -30%;
      width: 160%; height: 160%;
      background:
        radial-gradient(ellipse 400px 500px at 60% 25%, rgba(0,0,0,0.02), transparent),
        radial-gradient(ellipse 500px 300px at 35% 60%, rgba(0,0,0,0.03), transparent);
      animation: smokeDrift2 24s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    .s3-left {
      width: 46%;
      display: flex;
      flex-direction: column;
      justify-content: center;
      padding: 5rem 2.5rem 5rem 4rem;
      gap: 2.2rem;
      z-index: 2;
      position: relative;
    }
    .s3-left h2 {
      font-family: 'DM Serif Display', serif;
      font-size: clamp(2.4rem, 4vw, 3.4rem);
      font-weight: 400;
      font-style: italic;
      letter-spacing: -0.01em;
      line-height: 1.18;
      color: #171a20;
      text-shadow: 0 2px 8px rgba(0,0,0,0.08);
    }
    .s3-lead {
      font-size: 1.05rem;
      line-height: 1.75;
      color: #666;
      max-width: 440px;
    }
    .s3-lead strong {
      color: #222;
      font-weight: 600;
    }
    .s3-divider {
      width: 40px;
      height: 1px;
      background: rgba(0,0,0,0.12);
    }
    .s3-quote {
      font-size: 0.92rem;
      line-height: 1.65;
      color: #888;
      font-style: italic;
      padding-left: 1.2rem;
      border-left: 2px solid rgba(0,0,0,0.10);
      max-width: 380px;
    }

    /* Right column — stacked comparison */
    .s3-right {
      width: 54%;
      display: flex;
      flex-direction: column;
      justify-content: center;
      padding: 4rem 4rem 4rem 2.5rem;
      gap: 1.5rem;
      position: relative;
      z-index: 2;
    }
    .s3-versus {
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
    }
    .s3-vs-label {
      font-size: 0.78rem;
      font-weight: 600;
      letter-spacing: 0.12em;
      text-transform: uppercase;
      color: #999;
    }
    .s3-model {
      padding: 1.5rem 1.6rem;
      border-radius: 16px;
      display: flex;
      flex-direction: column;
      gap: 0.6rem;
    }
    .s3-model.cardboard {
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .s3-model.virentis {
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .s3-model-title {
      font-size: 0.78rem;
      font-weight: 600;
      letter-spacing: 0.05em;
      text-transform: uppercase;
      color: #777;
    }
    .s3-model-desc {
      font-size: 0.84rem;
      line-height: 1.6;
      color: #888;
    }
    .s3-model-highlight {
      font-size: 1.8rem;
      font-weight: 700;
      color: #171a20;
      text-shadow: 0 2px 6px rgba(0,0,0,0.08);
      letter-spacing: -0.02em;
      margin-top: 0.3rem;
    }
    .s3-model-highlight small {
      font-size: 0.75rem;
      font-weight: 400;
      color: #999;
      margin-left: 0.4rem;
    }

    /* Bottom insight row */
    .s3-insight {
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      gap: 0.7rem;
      margin-top: 0.3rem;
    }
    .s3-insight-card {
      padding: 1.1rem 1.2rem;
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-radius: 14px;
      display: flex;
      flex-direction: column;
      gap: 0.3rem;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .s3-insight-num {
      font-size: 1.5rem;
      font-weight: 700;
      color: #171a20;
      text-shadow: 0 1px 4px rgba(0,0,0,0.06);
    }
    .s3-insight-lbl {
      font-size: 0.68rem;
      color: #888;
      line-height: 1.35;
    }

    @media (max-width: 700px) {
      #s3 { flex-direction: column; }
      .s3-left, .s3-right { width: 100%; padding: 2rem; }
    }

    /* S3 economic calculator */
    .s3-calc {
      margin-top: 0.8rem;
      display: flex;
      flex-direction: column;
      gap: 0.6rem;
    }
    .s3-calc-row {
      display: flex;
      gap: 1rem;
    }
    .s3-calc-field {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 0.3rem;
    }
    .s3-calc-field label {
      font-size: 0.64rem;
      font-weight: 500;
      color: #888;
    }
    .s3-calc-input {
      display: flex;
      align-items: center;
      gap: 0.6rem;
    }
    .s3-calc-input input[type="range"] {
      flex: 1;
      -webkit-appearance: none;
      appearance: none;
      height: 3px;
      background: #d5d5d5;
      border-radius: 2px;
      outline: none;
    }
    .s3-calc-input input[type="range"]::-webkit-slider-thumb {
      -webkit-appearance: none;
      width: 13px;
      height: 13px;
      border-radius: 50%;
      background: #171a20;
      cursor: pointer;
    }
    .s3-calc-input input[type="number"] {
      width: 58px;
      background: #fff;
      border: 1px solid #ddd;
      border-radius: 5px;
      padding: 0.3rem 0.4rem;
      font-size: 0.78rem;
      font-family: 'Inter', sans-serif;
      color: #222;
      text-align: center;
      outline: none;
    }
    .s3-calc-input input[type="number"]:focus {
      border-color: #999;
    }
    .highlight-card {
      background: #f0faf0 !important;
      border-color: rgba(0,0,0,0.15) !important;
    }
    .highlight-card .s3-insight-num {
      color: #2d8f2d;
    }

    /* SECTION 4: Comparison Calculator */
    #s4 {
      background: #e8e8e8;
      flex-direction: row;
      align-items: stretch;
      justify-content: stretch;
      color: #222;
      overflow: hidden;
      position: relative;
    }
    #s4::before {
      content: '';
      position: absolute; inset: -40%;
      width: 180%; height: 180%;
      background:
        radial-gradient(ellipse 700px 500px at 25% 35%, rgba(0,0,0,0.055), transparent),
        radial-gradient(ellipse 500px 600px at 65% 75%, rgba(0,0,0,0.04), transparent),
        radial-gradient(ellipse 400px 300px at 50% 20%, rgba(0,0,0,0.03), transparent);
      animation: smokeDrift 20s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    #s4::after {
      content: '';
      position: absolute; inset: -30%;
      width: 160%; height: 160%;
      background:
        radial-gradient(ellipse 500px 500px at 75% 25%, rgba(0,0,0,0.035), transparent),
        radial-gradient(ellipse 600px 400px at 15% 65%, rgba(0,0,0,0.045), transparent);
      animation: smokeDrift2 24s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    .s4-left {
      width: 70%;
      display: flex;
      flex-direction: column;
      justify-content: center;
      padding: 5rem 3rem 4rem 3rem;
      gap: 2.5rem;
      z-index: 2;
      position: relative;
    }
    
    .s4-top {
      margin-bottom: 3rem;
    }
    .s4-top h2 {
      font-family: 'DM Serif Display', serif;
      font-size: clamp(2.4rem, 4vw, 3.4rem);
      font-weight: 400;
      font-style: italic;
      letter-spacing: -0.01em;
      margin: 0 0 0.6rem 0;
      color: #171a20;
      text-shadow: 0 2px 8px rgba(0,0,0,0.08);
      line-height: 1.18;
    }
    .s4-top p {
      font-size: 0.8rem;
      color: #999;
      line-height: 1.5;
      margin: 0;
    }

    /* Input row - single line */
    .s4-input-row {
      display: flex;
      align-items: center;
      gap: 0.8rem;
      padding: 0.9rem 1.2rem;
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-radius: 14px;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .s4-input-label {
      font-size: 0.82rem;
      font-weight: 600;
      color: #555;
      margin-bottom: 0.4rem;
    }
    .s4-input-row input[type="range"] {
      flex: 1;
      -webkit-appearance: none;
      appearance: none;
      height: 3px;
      background: #d5d5d5;
      border-radius: 2px;
      outline: none;
    }
    .s4-input-row input[type="range"]::-webkit-slider-thumb {
      -webkit-appearance: none;
      width: 12px;
      height: 12px;
      border-radius: 50%;
      background: #171a20;
      cursor: pointer;
    }
    .s4-input-row input[type="number"] {
      width: 70px;
      padding: 0.35rem 0.5rem;
      font-size: 0.8rem;
      font-family: 'Inter', sans-serif;
      color: #222;
      text-align: center;
      border: 1px solid #ddd;
      border-radius: 5px;
      background: #fafafa;
      outline: none;
      flex-shrink: 0;
    }
    .s4-input-row input[type="number"]:focus {
      border-color: #999;
      background: #fff;
    }
    .eq-sign {
      font-size: 1.1rem;
      font-weight: 300;
      color: #bbb;
      margin: 0 0.3rem;
      flex-shrink: 0;
    }
    .derived-box {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      padding-left: 0.8rem;
      border-left: 1px solid #e5e5e5;
      flex-shrink: 0;
    }
    .derived-num {
      font-size: 1.8rem;
      font-weight: 700;
      color: #171a20;
      letter-spacing: -0.02em;
      min-width: 80px;
      text-align: right;
    }
    .derived-labels {
      display: flex;
      flex-direction: column;
      gap: 0.1rem;
    }
    .derived-title {
      font-size: 0.58rem;
      font-weight: 700;
      letter-spacing: 0.04em;
      color: #777;
      text-transform: uppercase;
    }
    .derived-note {
      font-size: 0.62rem;
      color: #888;
    }

    /* 3 metric cards in row */
    .s4-cards {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 0.8rem;
    }
    .metric-card {
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-radius: 14px;
      padding: 0.9rem 0.8rem;
      display: flex;
      flex-direction: column;
      gap: 0.2rem;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .metric-val {
      font-size: 1.15rem;
      font-weight: 700;
      color: #171a20;
      text-shadow: 0 1px 4px rgba(0,0,0,0.06);
      letter-spacing: -0.02em;
    }
    .metric-lbl {
      font-size: 0.62rem;
      font-weight: 500;
      color: #777;
      line-height: 1.3;
    }

    .s4-assumptions {
      font-size: 0.62rem;
      color: #888;
      line-height: 1.3;
      margin: 0;
    }

    .metric-desc {
      font-size: 0.72rem;
      line-height: 1.55;
      color: #999;
      margin-top: 0.5rem;
      padding-top: 0.5rem;
      border-top: 1px solid rgba(0,0,0,0.08);
    }

    /* Break-even section - large 14 on left */
    .s4-breakeven {
      display: flex;
      align-items: flex-start;
      gap: 2.5rem;
      margin-top: 1rem;
      margin-bottom: 5rem;
    }
    .breakeven-num {
      flex-shrink: 0;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 1.5rem 2rem;
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-radius: 16px;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .be-big {
      font-size: clamp(4rem, 7vw, 6rem);
      font-weight: 800;
      color: #171a20;
      letter-spacing: -0.04em;
      line-height: 0.9;
    }
    .be-label {
      font-size: 0.64rem;
      font-weight: 600;
      color: #999;
      letter-spacing: 0.06em;
      margin-top: 0.4rem;
    }
    .breakeven-text {
      display: flex;
      flex-direction: column;
      gap: 0.8rem;
      padding-top: 0.5rem;
    }
    .breakeven-text p {
      font-size: 0.9rem;
      line-height: 1.6;
      color: #666;
      margin: 0;
    }
    .gain-highlight {
      font-weight: 600;
      color: #171a20 !important;
      background: #fff;
      padding: 0.8rem 1rem;
      border-radius: 12px;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-left: 3px solid #555;
      margin-top: 0.4rem !important;
      font-size: 0.92rem;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }

        .s4-glass { width:30%; position:relative; overflow:hidden; min-height:100%; z-index: 2; }
    .s4-glass-bg {
      position:absolute; inset:0;
      width:100%; height:100%;
      object-fit:cover;
    }


    @media (max-width:700px) {
      #s4 { flex-direction: column; }
      .s4-left { width: 100%; padding: 3rem 1.5rem 2rem; gap: 1.5rem; }
      .s4-top { margin-bottom: 1.5rem; }
      .s4-glass { width: 100%; height: 120px; }
      .s4-input-row { flex-wrap: wrap; gap: 0.5rem; }
      .eq-sign { display: none; }
      .derived-box { border-left: none; padding-left: 0; border-top: 1px solid #e5e5e5; padding-top: 0.6rem; width: 100%; }
      .derived-num { font-size: 1.4rem; min-width: auto; text-align: left; }
      .s4-cards { grid-template-columns: 1fr; }
      .s4-breakeven { flex-direction: column; gap: 1.2rem; margin-bottom: 2rem; }
      .breakeven-num { align-self: flex-start; }
    }

    /* SECTION 5: Customers & PPWR */
    #s5 {
      background: #e8e8e8;
      flex-direction: column;
      align-items: flex-start;
      justify-content: center;
      color: #171a20;
      overflow: hidden;
      position: relative;
      padding: 5rem 4rem 5rem 4.5rem;
    }
    #s5::before {
      content: '';
      position: absolute; inset: -40%;
      width: 180%; height: 180%;
      background:
        radial-gradient(ellipse 600px 500px at 30% 40%, rgba(0,0,0,0.05), transparent),
        radial-gradient(ellipse 500px 600px at 70% 70%, rgba(0,0,0,0.04), transparent),
        radial-gradient(ellipse 400px 350px at 55% 15%, rgba(0,0,0,0.03), transparent);
      animation: smokeDrift 20s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    #s5::after {
      content: '';
      position: absolute; inset: -30%;
      width: 160%; height: 160%;
      background:
        radial-gradient(ellipse 500px 450px at 80% 30%, rgba(0,0,0,0.035), transparent),
        radial-gradient(ellipse 550px 400px at 20% 60%, rgba(0,0,0,0.04), transparent);
      animation: smokeDrift2 24s ease-in-out infinite alternate;
      pointer-events: none; z-index: 0;
    }
    .s5-content {
      position: relative;
      z-index: 2;
      max-width: 55%;
      display: flex;
      flex-direction: column;
      gap: 1.8rem;
    }
    .s5-block {
      display: flex;
      flex-direction: column;
      gap: 1.2rem;
      padding: 2.2rem 2.5rem;
      background: #fff;
      border: 1.5px solid rgba(0,0,0,0.06);
      border-radius: 18px;
      box-shadow:
        0 1px 2px rgba(0,0,0,0.07),
        0 4px 8px rgba(0,0,0,0.07),
        0 8px 16px rgba(0,0,0,0.08),
        0 16px 32px rgba(0,0,0,0.10),
        0 32px 64px rgba(0,0,0,0.12);
    }
    .s5-block h2 {
      font-family: 'DM Serif Display', serif;
      font-size: clamp(2.8rem, 4.5vw, 3.8rem);
      font-weight: 400;
      font-style: italic;
      letter-spacing: -0.01em;
      line-height: 1.12;
      color: #171a20;
      text-shadow: 0 2px 8px rgba(0,0,0,0.08);
      margin: 0;
    }
    .s5-block p {
      font-size: 1.05rem;
      line-height: 1.8;
      color: #555;
      margin: 0;
      max-width: 640px;
    }
    .s5-block p strong {
      color: #222;
      font-weight: 600;
    }

    /* Button bar: s5 state — enlarged, right-center */
    #btnBar.s5-state {
      top: 50%;
      left: calc(100% - 16rem);
      transform: translate(-50%, -50%) scale(2);
    }

    @media (max-width: 700px) {
      #s5 { padding: 3rem 2rem; }
      .s5-content { max-width: 100%; gap: 2rem; }
      #btnBar.s5-state {
        left: 50%;
        transform: translate(-50%, -50%) scale(1.5);
      }
    }

    /* DEMO OVERLAY — modal style */
    #demoOverlay {
      position: fixed; inset: 0; z-index: 300;
      display: flex;
      align-items: center;
      justify-content: center;
      pointer-events: none;
      opacity: 0;
      transition: opacity 0.4s cubic-bezier(0.4,0,0.2,1);
    }
    #demoOverlay.open {
      pointer-events: auto;
      opacity: 1;
    }
    .demo-backdrop {
      position: absolute; inset: 0;
      background: rgba(0,0,0,0.55);
      backdrop-filter: blur(8px);
      -webkit-backdrop-filter: blur(8px);
      cursor: pointer;
    }
    .demo-modal {
      position: relative;
      z-index: 1;
      width: 90%;
      max-width: 840px;
      max-height: 88vh;
      overflow-y: auto;
      background: #1c1f26;
      border-radius: 20px;
      box-shadow:
        0 8px 32px rgba(0,0,0,0.4),
        0 32px 80px rgba(0,0,0,0.3);
      transform: translateY(30px) scale(0.96);
      opacity: 0;
      transition: transform 0.5s 0.1s cubic-bezier(0.4,0,0.2,1), opacity 0.4s 0.1s ease;
    }
    #demoOverlay.open .demo-modal {
      transform: translateY(0) scale(1);
      opacity: 1;
    }
    .demo-modal::-webkit-scrollbar { display: none; }
    .demo-modal { -ms-overflow-style: none; scrollbar-width: none; }

    .demo-modal-close {
      position: absolute;
      top: 1.2rem; right: 1.4rem;
      width: 36px; height: 36px;
      border-radius: 50%;
      border: 1px solid rgba(255,255,255,0.12);
      background: rgba(255,255,255,0.04);
      color: rgba(255,255,255,0.5);
      font-size: 0.95rem;
      cursor: pointer;
      display: flex; align-items: center; justify-content: center;
      transition: all 0.3s ease;
      font-family: 'Inter', sans-serif;
      line-height: 1;
      z-index: 2;
    }
    .demo-modal-close:hover {
      background: rgba(255,255,255,0.1);
      border-color: rgba(255,255,255,0.3);
      color: #fff;
    }

    .demo-page {
      display: flex; min-height: 0;
      color: #d0d0d0; font-family: 'Inter', sans-serif;
    }
    .demo-left {
      flex:1; display:flex; flex-direction:column; justify-content:center;
      padding:3rem 2.5rem; max-width:380px;
    }
    .demo-left h1 { font-size:1.6rem; font-weight:300; color:#fff; line-height:1.3; margin-bottom:1rem; letter-spacing:0.02em; }
    .demo-left p { font-size:0.9rem; line-height:1.7; color:#8a8e96; margin-bottom:2rem; }
    .demo-left .features { display:flex; flex-direction:column; gap:0.8rem; }
    .demo-left .feat { display:flex; align-items:center; gap:0.7rem; font-size:0.82rem; color:#a0a4ac; }
    .demo-left .feat .dot { width:5px; height:5px; background:#555; border-radius:50%; flex-shrink:0; }

    .demo-divider { width:1px; background:rgba(255,255,255,0.08); margin:4rem 0; }

    .demo-right {
      flex:1.2; display:flex; align-items:center; justify-content:center; padding:2.5rem;
    }
    .form-card { width:100%; max-width:460px; }
    .form-card h2 { font-size:0.75rem; font-weight:500; letter-spacing:0.15em; text-transform:uppercase; color:#6a6e76; margin-bottom:2rem; }

    .form-row { display:flex; gap:1rem; margin-bottom:1.2rem; }
    .field { flex:1; display:flex; flex-direction:column; margin-bottom:1.2rem; }
    .form-row .field { margin-bottom:0; }
    .field label { font-size:0.72rem; font-weight:500; letter-spacing:0.08em; text-transform:uppercase; color:#666; margin-bottom:0.5rem; }
    .field input, .field select, .field textarea {
      background:#252830; border:1px solid #3a3e48; border-radius:8px;
      padding:0.75rem 0.9rem; font-size:0.88rem; font-family:'Inter',sans-serif;
      color:#e0e0e0; outline:none; transition:border-color 0.2s;
    }
    .field input::placeholder, .field textarea::placeholder { color:#5a5e66; }
    .field input:focus, .field select:focus, .field textarea:focus { border-color:#5a5e66; }
    .field textarea { resize:vertical; min-height:80px; }
    .field select {
      appearance:none; -webkit-appearance:none;
      background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%23666' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E");
      background-repeat:no-repeat; background-position:right 0.9rem center; padding-right:2.2rem;
    }
    .field select option { background:#252830; color:#d0d0d0; }

    .submit-btn {
      width:100%; padding:0.85rem; border:none; border-radius:10px;
      background:#fff; color:#1c1f26; font-size:0.88rem; font-weight:500;
      font-family:'Inter',sans-serif; letter-spacing:0.02em; cursor:pointer;
      transition:background 0.2s, transform 0.1s; margin-top:0.5rem;
    }
    .submit-btn:hover { background:#e0e0e0; }
    .submit-btn:active { transform:scale(0.99); }

    .disclaimer { font-size:0.7rem; color:#5a5e66; margin-top:1.2rem; line-height:1.5; }

    .success-msg { display:none; text-align:center; padding:3rem 0; }
    .success-msg .check {
      width:48px; height:48px; border:2px solid #444; border-radius:50%;
      display:flex; align-items:center; justify-content:center; margin:0 auto 1.5rem auto;
    }
    .success-msg h3 { font-size:1.1rem; font-weight:400; color:#fff; margin-bottom:0.6rem; }
    .success-msg p { font-size:0.85rem; color:#666; }

    @media (max-width:800px) {
      .demo-page { flex-direction:column; }
      .demo-left { max-width:100%; padding:2rem; }
      .demo-divider { width:100%; height:1px; margin:0; }
      .demo-right { padding:2rem; }
      .demo-modal { width: 96%; max-height: 92vh; border-radius: 14px; }
    }


    /* 13-inch laptop adjustments */
    @media (max-width: 1440px) and (min-width: 601px) {
      .s2-header { left: 3rem; max-width: 420px; }
      .s2-header h2 { font-size: clamp(2rem, 3.5vw, 2.8rem); }
      .s2-header .s2-sub { font-size: clamp(1.1rem, 1.8vw, 1.4rem); }
      .s2-panel { width: 44vw; right: 160px; padding: 2rem 2.2rem; }
      .s2-sidebar { width: 150px; padding: 2.5rem 1.2rem 2.5rem 0; gap: 0.6rem; }
      .s2-card { min-height: 100px; }
      .s2-card-icon { width: 42px; height: 42px; }

      .s3-left { padding: 4rem 2rem 4rem 3rem; }
      .s3-left h2 { font-size: clamp(2rem, 3.5vw, 2.8rem); }
      .s3-right { padding: 3rem 3rem 3rem 2rem; }

      .s4-left { padding: 4rem 2.5rem 3rem 2.5rem; gap: 2rem; }
      .s4-top { margin-bottom: 2rem; }
      .s4-top h2 { font-size: clamp(2rem, 3.5vw, 2.8rem); }
      .s4-breakeven { gap: 2rem; margin-bottom: 3rem; }
      .be-big { font-size: clamp(3.5rem, 5.5vw, 5rem); }

      #s5 { padding: 4rem 3rem 4rem 3.5rem; }
      .s5-block h2 { font-size: clamp(2.4rem, 4vw, 3.2rem); }
    }

    /* ===== MOBILE MASTER ===== */
    @media (max-width: 600px) {

      /* Disable snap scroll — content overflows on mobile */
      #scroll-container {
        scroll-snap-type: none;
      }
      section {
        height: auto;
        min-height: 100vh;
        scroll-snap-align: none;
        scroll-snap-stop: normal;
      }

      /* Nav */
      nav { padding: 1rem 1.2rem; }
      nav .logo { font-size: 1rem; }

      /* Button bar */
      #btnBar {
        top: auto;
        bottom: 1.2rem;
        left: 50%;
        transform: translateX(-50%);
        transition: opacity 0.4s ease, transform 0.4s ease;
      }
      #btnBar.s5-state {
        top: auto;
        bottom: 1.2rem;
        left: 50%;
        transform: translateX(-50%) scale(1.15);
      }
      .btn {
        padding: 0.65rem 2rem;
        font-size: 0.82rem;
        min-width: 170px;
        border-radius: 6px;
      }

      /* S1 Hero */
      #s1 { min-height: 100vh; }
      .hero-heading {
        font-size: clamp(1.4rem, 6vw, 2rem);
        top: 22%;
        white-space: normal;
        width: 85%;
        text-align: center;
      }
      .hero-tagline {
        font-size: clamp(0.85rem, 3.5vw, 1.1rem);
        top: 38%;
        white-space: normal;
        width: 85%;
        text-align: center;
      }
      .scroll-arrow { bottom: 5rem; }

      /* S2 Package functions */
      #s2 { min-height: 100vh; height: auto; }
      .s2-layout {
        height: auto;
        display: flex;
        flex-direction: column;
      }
      .s2-header {
        position: relative;
        top: auto; left: auto;
        transform: none;
        padding: 4rem 1.5rem 1.5rem;
        max-width: 100%;
      }
      .s2-header h2 { font-size: clamp(1.6rem, 6vw, 2.2rem); }
      .s2-header .s2-sub { font-size: 1rem; margin-top: 0.6rem; }
      .s2-body {
        position: relative;
        inset: auto;
        flex-direction: column;
        align-items: stretch;
      }
      .s2-expand-area {
        order: 2;
      }
      .s2-sidebar {
        order: 1;
        width: 100%;
        flex-direction: row;
        padding: 0.8rem 1.2rem;
        overflow-x: auto;
        gap: 0.6rem;
      }
      .s2-card {
        min-height: 70px;
        min-width: 90px;
        padding: 0.6rem 0.5rem;
      }
      .s2-card-icon { width: 36px; height: 36px; }
      .s2-card-title { font-size: 0.58rem; }
      .s2-panel {
        position: relative;
        top: auto; right: auto;
        width: calc(100% - 2.4rem);
        margin: 0.8rem 1.2rem 2rem;
        height: auto;
        min-height: 0;
        max-height: none;
        padding: 1.8rem 1.5rem;
        border-radius: 14px;
        transform: scale(0);
        opacity: 0;
      }
      .s2-panel.open {
        transform: scale(1);
        opacity: 1;
      }
      .s2-exp-icon { width: 32px; height: 32px; margin-bottom: 0.8rem; }
      .s2-exp-title { font-size: 1.15rem; margin-bottom: 0.8rem; }
      .s2-exp-divider { margin-bottom: 1rem; }
      .s2-exp-text { font-size: 0.82rem; line-height: 1.7; }
      .s2-exp-text p { margin-bottom: 0.8rem; }

      /* S3 Economics */
      #s3 {
        flex-direction: column;
        height: auto;
        min-height: 100vh;
      }
      .s3-left {
        width: 100%;
        padding: 4rem 1.5rem 1.5rem;
        gap: 1.2rem;
      }
      .s3-left h2 { font-size: clamp(1.6rem, 6vw, 2.2rem); }
      .s3-lead { font-size: 0.9rem; }
      .s3-quote { font-size: 0.82rem; }
      .s3-right {
        width: 100%;
        padding: 1rem 1.5rem 2rem;
        gap: 1rem;
      }
      .s3-model { padding: 1.2rem; }
      .s3-model-highlight { font-size: 1.3rem; }
      .s3-insight { grid-template-columns: 1fr; gap: 0.5rem; }
      .s3-insight-num { font-size: 1.2rem; }
      .s3-calc-input input[type="range"] { min-width: 0; }

      /* Box animation — hide on mobile */
      .box-anim-wrap { display: none; }

      /* S4 Calculator */
      #s4 {
        flex-direction: column;
        height: auto;
        min-height: 100vh;
      }
      .s4-left {
        width: 100%;
        padding: 4rem 1.5rem 2rem;
        gap: 1.5rem;
      }
      .s4-top { margin-bottom: 1rem; }
      .s4-top h2 { font-size: clamp(1.6rem, 6vw, 2.2rem); }
      .s4-input-label { font-size: 0.76rem; }
      .s4-input-row {
        flex-wrap: wrap;
        gap: 0.5rem;
        padding: 0.8rem 1rem;
      }
      .s4-input-row input[type="range"] { width: 100%; order: 1; }
      .s4-input-row input[type="number"] { order: 2; }
      .eq-sign { display: none; }
      .derived-box {
        order: 3;
        width: 100%;
        border-left: none;
        padding-left: 0;
        border-top: 1px solid #e5e5e5;
        padding-top: 0.6rem;
      }
      .derived-num { font-size: 1.4rem; min-width: auto; text-align: left; }
      .s4-cards { grid-template-columns: 1fr; gap: 0.6rem; }
      .metric-card { padding: 1rem; }
      .metric-desc { font-size: 0.68rem; }
      .s4-breakeven {
        flex-direction: column;
        gap: 1rem;
        margin-top: 0.5rem;
        margin-bottom: 2rem;
      }
      .breakeven-num { align-self: flex-start; padding: 1rem 1.5rem; }
      .be-big { font-size: 3.5rem; }
      .breakeven-text p { font-size: 0.82rem; }
      .gain-highlight { font-size: 0.82rem; padding: 0.6rem 0.8rem; }
      .s4-glass { width: 100%; height: 100px; }

      /* S5 Customers & PPWR */
      #s5 {
        height: auto;
        min-height: 100vh;
        padding: 4rem 1.5rem 5rem;
      }
      .s5-content { max-width: 100%; gap: 1.2rem; }
      .s5-block {
        padding: 1.5rem 1.2rem;
        border-radius: 14px;
      }
      .s5-block h2 { font-size: clamp(1.5rem, 5.5vw, 2rem); }
      .s5-block p { font-size: 0.9rem; line-height: 1.7; }

      /* Demo modal */
      .demo-modal {
        width: 100%;
        max-height: 100vh;
        border-radius: 0;
        margin: 0;
      }
      .demo-page { flex-direction: column; }
      .demo-left { padding: 2rem 1.5rem 1rem; max-width: 100%; }
      .demo-left h1 { font-size: 1.3rem; }
      .demo-left p { font-size: 0.82rem; }
      .demo-left .feat { font-size: 0.76rem; }
      .demo-divider { width: 100%; height: 1px; margin: 0; }
      .demo-right { padding: 1.5rem; }
      .form-card h2 { font-size: 0.7rem; }
      .field input, .field select, .field textarea { font-size: 0.82rem; padding: 0.65rem 0.8rem; }
      .field label { font-size: 0.65rem; }
      .submit-btn { font-size: 0.82rem; }
    }