:root {
    /* Palette */
    --black: #0b0b0d;
    --black-2: #0f0f11;
    --black-3: #141418;
    --black-4: #1a1a20;
    --rule: rgba(255, 255, 255, 0.08);
    --rule-2: rgba(255, 255, 255, 0.04);
    --ink: #f5f3ee;
    --ink-2: #d4d1c9;
    --ink-dim: #8a8680;
    --ink-faint: #4a4842;
    --gold: #c9a961;           /* Logo-derived warm gold */
    --gold-light: #dcc08a;
    --gold-deep: #7d6838;
    --gold-glow: rgba(201, 169, 97, 0.15);
  }

  * { margin: 0; padding: 0; box-sizing: border-box; }
  html {
    scroll-behavior: auto;
    font-size: 16px;
    zoom: 0.86;
  }
  body {
    background: var(--black);
    color: var(--ink);
    font-family: 'Inter', -apple-system, sans-serif;
    font-weight: 400;
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    letter-spacing: -0.003em;
  }

  /* ============ TYPOGRAPHY SYSTEM ============ */
  .mono {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 500;
    font-size: 0.864rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }
  .serif-italic { display: none; }

  /* ============ NOISE TEXTURE (very subtle) ============ */
  body::before {
    content: '';
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 1000;
    opacity: 0.025;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='120' height='120'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
  }

  /* ============ NAV ============ */
  nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 0.9rem 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.4s ease;
    background: transparent;
  }
  nav.scrolled {
    padding: 0.5rem 2.5rem;
    background: rgba(11, 11, 13, 0.85);
    backdrop-filter: blur(20px) saturate(120%);
    -webkit-backdrop-filter: blur(20px) saturate(120%);
    border-bottom: 1px solid var(--rule-2);
  }
  .logo {
    display: flex;
    align-items: center;
    gap: 0.9rem;
    cursor: pointer;
  }
  .logo img {
    height: 116px;
    width: auto;
    object-fit: contain;
    display: block;
  }
  .logo-text {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: 0.88rem;
    letter-spacing: 0.18em;
    line-height: 1.2;
    text-transform: uppercase;
  }
  .logo-text .top { color: var(--ink); font-weight: 500; }
  .logo-text .bot { color: var(--ink-dim); font-weight: 300; }

  .nav-links {
    display: flex;
    gap: 2.8rem;
    align-items: center;
  }
  .nav-links a {
    color: var(--ink-2);
    text-decoration: none;
    font-size: 0.82rem;
    font-weight: 400;
    letter-spacing: 0.01em;
    transition: color 0.3s ease;
  }
  .nav-links a:not(.nav-cta):hover { color: var(--gold); }
  .nav-cta {
    border: 1px solid var(--rule);
    padding: 0.65rem 1.3rem;
    border-radius: 100px;
    color: var(--ink) !important;
    font-size: 0.78rem !important;
    transition: all 0.3s ease !important;
  }
  .nav-cta:hover {
    border-color: var(--gold);
    background: var(--gold-glow);
    color: var(--gold) !important;
  }
  .nav-toggle {
    display: none;
    background: none; border: none;
    color: var(--ink); cursor: pointer;
    padding: 0.5rem;
  }

  /* ============ HERO ============ */
  .hero {
    min-height: 100vh;
    position: relative;
    padding: 9rem 2.5rem 5rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    overflow: hidden;
  }
  .hero-bg {
    position: absolute;
    inset: 0;
    z-index: 1;
    overflow: hidden;
  }
  .hero-bg-img {
    position: absolute;
    top: 0; right: 0;
    width: 100%;
    height: 100%;
    background-image: url("assets/16pic_9043318.jpg");
    background-size: cover;
    background-position: center center;
    background-repeat: no-repeat;
    opacity: 0.6;
    filter: grayscale(0.2) contrast(1.05);
  }
  .hero-bg-img::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(
      ellipse 70% 55% at 70% 50%,
      rgba(201, 169, 97, 0.18) 0%,
      transparent 65%
    );
  }
  .hero-vignette {
    position: absolute;
    inset: 0;
    z-index: 2;
    background:
      linear-gradient(90deg, var(--black) 0%, rgba(11,11,13,0.75) 30%, rgba(11,11,13,0.1) 60%, rgba(11,11,13,0.4) 100%),
      linear-gradient(180deg, rgba(11,11,13,0.5) 0%, transparent 25%, transparent 75%, rgba(11,11,13,0.85) 100%);
    pointer-events: none;
  }
  .hero-content {
    position: relative;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    z-index: 5;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: 0;
  }
  .hero-inner {
    max-width: 900px;
  }
  .hero-eyebrow {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 3rem;
    opacity: 0;
  }
  .hero-eyebrow::before {
    content: '';
    width: 32px;
    height: 1px;
    background: var(--gold);
    display: block;
  }
  .hero h1 {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: clamp(2.25rem, 4.2vw, 4rem);
    letter-spacing: -0.025em;
    line-height: 1.15;
    margin-bottom: 2.5rem;
    color: var(--ink);
    white-space: nowrap;
  }
  .hero h1 .line {
    display: block;
    opacity: 0;
    transform: translateY(20px);
  }
  .hero h1 em {
    font-style: normal;
    color: var(--gold);
    font-weight: 500;
  }
  .hero-sub {
    font-size: clamp(1.1rem, 1.35vw, 1.25rem);
    color: var(--ink-2);
    max-width: 54ch;
    margin-bottom: 3.5rem;
    line-height: 1.6;
    font-weight: 400;
    opacity: 0;
  }
  .hero-ctas {
    display: flex;
    gap: 0.8rem;
    flex-wrap: wrap;
    opacity: 0;
  }
  .btn {
    display: inline-flex;
    align-items: center;
    gap: 0.7rem;
    padding: 1.05rem 2rem;
    font-family: 'Inter', sans-serif;
    font-size: 0.88rem;
    font-weight: 400;
    letter-spacing: 0.01em;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 100px;
    border: 1px solid transparent;
    white-space: nowrap;
  }
  .btn-primary {
    background: var(--gold);
    color: var(--black);
    font-weight: 500;
  }
  .btn-primary:hover {
    background: var(--gold-light);
    transform: translateY(-1px);
    box-shadow: 0 0 30px rgba(201, 169, 97, 0.8), 0 0 60px rgba(201, 169, 97, 0.4), 0 12px 40px -12px rgba(201, 169, 97, 0.6);
  }
  .btn-ghost {
    background: transparent;
    color: var(--ink);
    border-color: var(--rule);
  }
  .btn-ghost:hover {
    border-color: var(--gold);
    color: var(--gold);
  }
  .btn .arrow {
    transition: transform 0.3s ease;
    font-size: 1.1em;
  }
  .btn:hover .arrow { transform: translateX(3px); }

  /* Hero side callout */
  .hero-side-text {
    position: absolute;
    right: 3rem;
    top: 9rem;
    z-index: 5;
    width: 360px;
    opacity: 0;
    border-left: 2px solid var(--gold);
    padding-left: 1.25rem;
  }
  .hsx-underline {
    color: var(--gold);
  }
  .hsx-title {
    font-family: 'Inter', sans-serif;
    font-size: 2rem;
    font-weight: 500;
    color: var(--ink);
    letter-spacing: -0.01em;
    margin-bottom: 0.85rem;
  }
  .hsx-stack {
    position: relative;
    height: 10rem;
    margin-top: 1rem;
  }
  .hsx-card {
    position: absolute;
    top: 50%;
    left: 50%;
    padding: 0.85rem 1.4rem;
    border-radius: 0.7rem;
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    font-size: 1.55rem; /* fixed — scale() handles visual sizing */
    letter-spacing: -0.01em;
    line-height: 1.2;
    white-space: nowrap;
    pointer-events: none;
    will-change: transform, opacity;
    -webkit-font-smoothing: antialiased;
    transition: transform 0.9s cubic-bezier(0.22, 1, 0.36, 1),
                opacity 0.9s ease,
                background-color 0.9s ease,
                color 0.9s ease,
                box-shadow 0.9s ease;
  }
  /* pos-0: hidden (cycling out) */
  .hsx-card.pos-0 {
    opacity: 0;
    background: rgba(255, 255, 255, 0.05);
    color: var(--ink-dim);
    border: 1px solid rgba(255, 255, 255, 0.08);
    transform: translate(-50%, -50%) translateY(-3.2rem) scale(0.74);
    z-index: 1;
  }
  /* pos-1: upper-back (above front) */
  .hsx-card.pos-1 {
    opacity: 0.6;
    background: rgba(255, 255, 255, 0.07);
    color: var(--ink-2);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transform: translate(-50%, -50%) translateY(-2.4rem) scale(0.74);
    z-index: 2;
  }
  /* pos-2: FRONT (active — gold highlight) */
  .hsx-card.pos-2 {
    opacity: 1;
    background: var(--gold);
    color: #0b0b0d;
    border: 1px solid transparent;
    box-shadow: 0 14px 40px rgba(0, 0, 0, 0.45),
                0 2px 6px rgba(0, 0, 0, 0.35);
    transform: translate(-50%, -50%) translateY(0) scale(1);
    z-index: 4;
  }
  /* pos-3: lower-back (below front, symmetric to pos-1) */
  .hsx-card.pos-3 {
    opacity: 0.6;
    background: rgba(255, 255, 255, 0.07);
    color: var(--ink-2);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transform: translate(-50%, -50%) translateY(2.4rem) scale(0.74);
    z-index: 2;
  }
  @media (max-width: 1024px) { .hero-side-text { display: none; } }

  /* Hero metrics row */
  .hero-metrics {
    position: relative;
    z-index: 5;
    max-width: 1400px;
    margin: 5rem auto 0;
    display: grid;
    grid-template-columns: repeat(3, max-content);
    gap: 5rem;
    padding-top: 2.5rem;
    border-top: 1px solid var(--rule-2);
    transition: padding 0.35s ease, gap 0.35s ease, background 0.35s ease, border-color 0.35s ease;
  }
  @keyframes circPulse {
    0%   { r: 6;  opacity: 0.9; }
    70%  { r: 24; opacity: 0; }
    100% { r: 24; opacity: 0; }
  }
  @keyframes metricsSlideIn {
    from { opacity: 0; transform: translateY(-110%); }
    to   { opacity: 1; transform: translateY(0); }
  }
  .hero-metrics.metrics-sticky {
    position: fixed;
    left: 0; right: 0;
    width: 100%;
    max-width: 100%;
    margin: 0;
    padding: 0.7rem 2.5rem;
    gap: 3.5rem;
    justify-content: center;
    background: rgba(11, 11, 13, 0.92);
    backdrop-filter: blur(22px) saturate(130%);
    -webkit-backdrop-filter: blur(22px) saturate(130%);
    border-top: none;
    border-bottom: 1px solid rgba(255,255,255,0.07);
    z-index: 99;
    animation: metricsSlideIn 0.45s cubic-bezier(0.22, 1, 0.36, 1) forwards;
  }
  .hero-metrics.metrics-sticky .metric-num {
    font-size: clamp(0.95rem, 1.5vw, 1.3rem);
    margin-bottom: 0.15rem;
    transition: font-size 0.45s cubic-bezier(0.22, 1, 0.36, 1);
  }
  .hero-metrics.metrics-sticky .metric-label {
    font-size: 0.55rem;
    transition: font-size 0.45s cubic-bezier(0.22, 1, 0.36, 1);
  }
  .metric { opacity: 0; }
  .metric-num {
    font-family: 'Inter', sans-serif;
    font-weight: 200;
    font-size: clamp(1.75rem, 2.8vw, 2.6rem);
    letter-spacing: -0.035em;
    line-height: 1;
    margin-bottom: 0.6rem;
    color: var(--ink);
  }
  .metric-num .suffix {
    color: var(--gold);
    font-weight: 300;
  }
  .metric-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    font-weight: 400;
  }

  /* ============ SECTION SCAFFOLD ============ */
  section {
    padding: 10rem 2.5rem;
    position: relative;
  }
  .container {
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    position: relative;
  }
  .section-header {
    margin-bottom: 6rem;
    max-width: 900px;
  }
  .section-eyebrow {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.8s ease;
  }
  .section-eyebrow.revealed { opacity: 1; transform: none; }
  .section-eyebrow::before {
    content: '';
    width: 24px; height: 1px;
    background: var(--gold);
  }
  .section-eyebrow span {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    letter-spacing: 0.26em;
    text-transform: uppercase;
    color: var(--gold);
    font-weight: 400;
  }
  .section-title {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: clamp(2rem, 4.5vw, 3.5rem);
    letter-spacing: -0.02em;
    line-height: 1.1;
    margin-bottom: 2rem;
    color: var(--ink);
  }
  .section-title em {
    font-style: normal;
    font-weight: 500;
    color: var(--gold);
  }
  .section-desc {
    font-size: 1.1rem;
    color: var(--ink-2);
    max-width: 62ch;
    line-height: 1.65;
    font-weight: 400;
  }
  .partnership-stats {
    list-style: none;
    margin: 1.75rem 0 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
    max-width: 62ch;
  }
  .partnership-stats li {
    font-family: 'Inter', sans-serif;
    font-size: 1.05rem;
    font-weight: 300;
    color: var(--ink-2);
    padding-left: 1.25rem;
    position: relative;
  }
  .partnership-stats li::before {
    content: '—';
    position: absolute;
    left: 0;
    color: var(--gold);
    font-weight: 400;
  }
  .partnership-stats li em {
    font-style: normal;
    font-weight: 500;
    color: var(--ink);
  }

  /* ============ PROBLEM STATEMENT BAND ============ */
  .problem {
    padding: 12rem 2.5rem;
    border-top: 1px solid var(--rule-2);
    border-bottom: 1px solid var(--rule-2);
    background: var(--black-2);
    position: relative;
    overflow: hidden;
  }
  .problem::before {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    width: 80vw;
    height: 60vh;
    background: radial-gradient(ellipse, rgba(201, 169, 97, 0.04) 0%, transparent 70%);
    pointer-events: none;
  }
  .problem-content {
    max-width: 1100px;
    margin: 0 auto;
    position: relative;
    z-index: 2;
  }
  .problem-quote {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: clamp(1.7rem, 4vw, 3.2rem);
    line-height: 1.25;
    letter-spacing: -0.02em;
    color: var(--ink);
  }
  .problem-quote em {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 500;
    color: var(--gold);
  }
  .problem-attribution {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    margin-top: 3rem;
    display: flex;
    align-items: center;
    gap: 1rem;
  }
  .problem-attribution::before {
    content: '';
    width: 24px; height: 1px;
    background: var(--ink-dim);
  }

  /* ============ SCIENCE ============ */
  .science {
    background: var(--black);
    position: relative;
    border-top: 1px solid var(--rule-2);
    padding-top: 7rem;
  }
  .science-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6rem;
    align-items: center;
    position: relative;
  }
  .science-viz-wrap {
    position: relative;
    aspect-ratio: 4/4.6;
    margin-top: 4rem;
    background: linear-gradient(135deg, var(--black-3) 0%, var(--black) 100%);
    border: 1px solid var(--rule-2);
    overflow: hidden;
  }
  .science-viz-label {
    position: absolute;
    top: 1.5rem; left: 1.5rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.22em;
    color: var(--gold);
    font-weight: 400;
    z-index: 5;
  }
  /* Additional material samples row */
  .science-samples {
    margin-top: 5rem;
  }
  .science-samples-header {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    margin-bottom: 1.75rem;
    justify-content: center;
  }
  .science-samples-bar {
    flex: 1;
    height: 1px;
    background: rgba(201, 169, 97, 0.25);
    max-width: 220px;
  }
  .science-samples-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    letter-spacing: 0.22em;
    color: var(--gold);
    text-transform: uppercase;
    white-space: nowrap;
  }
  .science-samples-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
  }
  .sample {
    position: relative;
    border: 1px solid var(--rule-2);
    background: var(--black-3);
    transition: border-color 0.4s ease;
  }
  .sample-img {
    aspect-ratio: 1/1.15;
    overflow: hidden;
    width: 100%;
  }
  .sample img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transform: scaleY(-1);
    transition: transform 0.6s ease;
  }
  .sample:hover { border-color: rgba(201, 169, 97, 0.5); }
  .sample:hover img { transform: scaleY(-1) scale(1.04); }
  .sample-cropped img { transform: scaleY(-1) scale(1.12); }
  .sample-cropped:hover img { transform: scaleY(-1) scale(1.16); }
  .sample-label {
    position: absolute;
    top: 0.55rem;
    left: 0.55rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.68rem;
    letter-spacing: 0.15em;
    color: var(--gold);
    background: rgba(0, 0, 0, 0.72);
    padding: 0.25rem 0.5rem;
    border: 1px solid rgba(201, 169, 97, 0.3);
    border-radius: 1px;
    z-index: 2;
    backdrop-filter: blur(4px);
  }
  .sample-thickness {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    letter-spacing: 0.12em;
    color: var(--gold);
    text-align: center;
    padding: 0.65rem 0.55rem 0.4rem;
  }
  @media (max-width: 1024px) {
    .science-samples-grid { grid-template-columns: repeat(3, 1fr); }
  }
  @media (max-width: 720px) {
    .science-samples-grid { grid-template-columns: repeat(2, 1fr); }
  }
  .science-viz-scale {
    position: absolute;
    top: 1.5rem; left: 1.5rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.72rem;
    color: var(--ink);
    letter-spacing: 0.08em;
    z-index: 5;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.35rem;
    background: rgba(0, 0, 0, 0.55);
    padding: 0.5rem 0.7rem;
    border-radius: 2px;
    backdrop-filter: blur(3px);
  }
  .science-viz-scale::before {
    content: '';
    width: 64px; height: 3px;
    background: var(--ink);
    box-shadow: 0 0 0 1px rgba(0,0,0,0.4);
  }
  .science-svg {
    width: 100%;
    height: 100%;
    display: block;
  }

  .science-layers {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 1.75rem;
    margin-top: 3rem;
  }
  .science-layers li {
    position: relative;
    display: grid;
    grid-template-columns: 2rem 1fr;
    gap: 1.5rem;
    padding: 1.25rem 0 1.25rem 1.25rem;
    border-bottom: 1px solid var(--rule-2);
    opacity: 0.6;
    transition: opacity 0.3s ease, background-color 0.3s ease;
  }
  .science-layers li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--gold);
    transform: scaleY(0);
    transform-origin: center;
    transition: transform 0.45s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.45s ease;
    opacity: 0;
    border-radius: 1px;
  }
  .science-layers li.active,
  .science-layers li:hover {
    opacity: 1;
    background-color: rgba(201, 169, 97, 0.07);
    cursor: default;
  }
  .science-layers li.active::before,
  .science-layers li:hover::before {
    transform: scaleY(1);
    opacity: 1;
  }
  .science-layers .num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    letter-spacing: 0.15em;
    color: var(--gold);
    padding-top: 0.25rem;
  }
  .science-layers .name {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 1.38rem;
    margin-bottom: 0.35rem;
    color: var(--ink);
    letter-spacing: -0.01em;
  }
  .science-layers .formula {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 300;
    color: var(--gold);
  }
  .science-layers .desc {
    color: var(--ink-dim);
    font-size: 1.1rem;
    line-height: 1.6;
  }

  /* ============ SCIENCE EXTENDED ============ */
  .science-extended {
    margin-top: 6rem;
    padding-top: 5rem;
    border-top: 1px solid var(--rule-2);
    display: flex;
    flex-direction: column;
    gap: 4rem;
  }
  .science-ext-block {
    max-width: 1100px;
  }
  .science-ext-heading {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: clamp(2rem, 4.5vw, 3.5rem);
    letter-spacing: -0.02em;
    line-height: 1.1;
    color: var(--ink);
    margin: 0 0 2rem;
    padding-bottom: 1.25rem;
    border-bottom: 2px solid var(--gold);
    width: fit-content;
    max-width: 100%;
  }
  .science-ext-heading em {
    font-style: normal;
    font-weight: 500;
    color: var(--gold);
  }
  .science-ext-body {
    font-size: 1.1rem;
    color: var(--ink-2);
    line-height: 1.7;
    font-weight: 300;
    max-width: 80ch;
    margin-top: 1.5rem;
  }
  .science-advantages {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    background: var(--rule-2);
    border: 1px solid var(--rule-2);
    margin-top: 2rem;
  }
  .science-adv-card {
    background: var(--black);
    padding: 2.5rem 2.25rem;
    transition: background 0.4s ease;
  }
  .science-adv-card:hover { background: var(--black-3); }
  .science-adv-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    color: var(--gold);
    margin-bottom: 1.25rem;
  }
  .science-adv-title {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 1.15rem;
    color: var(--ink);
    letter-spacing: -0.01em;
    margin-bottom: 1rem;
    line-height: 1.3;
  }
  .science-adv-desc {
    font-size: 0.92rem;
    color: var(--ink-2);
    line-height: 1.65;
    font-weight: 300;
  }
  .science-ext-callout {
    border-left: 3px solid var(--gold);
    padding: 1.75rem 2.5rem;
    background: rgba(201, 169, 97, 0.05);
    max-width: 900px;
  }
  .science-ext-callout p {
    font-size: 1.15rem;
    color: var(--ink-2);
    line-height: 1.7;
    font-weight: 300;
  }
  .science-ext-callout em {
    font-style: normal;
    font-weight: 500;
    color: var(--gold);
  }
  @media (max-width: 1024px) {
    .science-advantages { grid-template-columns: 1fr; }
  }

  /* ============ GRADES — refined hover cards ============ */
  .grades {
    background: var(--black-2);
    border-top: 1px solid var(--rule-2);
    border-bottom: 1px solid var(--rule-2);
  }
  .grades-track {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: auto auto auto auto auto;
    gap: 1px;
    background: var(--rule-2);
    margin-top: 4rem;
    border: 1px solid var(--rule-2);
  }
  .grade-card {
    background: var(--black-2);
    padding: 3.5rem 3rem;
    position: relative;
    display: grid;
    grid-template-rows: subgrid;
    grid-row: span 5;
    transition: all 0.5s cubic-bezier(0.2, 0.8, 0.2, 1);
    cursor: pointer;
    overflow: hidden;
  }
  .grade-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at top, var(--gold-glow) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
  }
  .grade-card:hover {
    background: var(--black-3);
  }
  .grade-card:hover::before { opacity: 1; }
  .grade-card-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.68rem;
    letter-spacing: 0.22em;
    color: var(--ink-dim);
    margin-bottom: 3rem;
    transition: color 0.4s;
  }
  .grade-card:hover .grade-card-num { color: var(--gold); }
  .grade-code {
    font-family: 'Inter', sans-serif;
    font-weight: 200;
    font-size: clamp(3.5rem, 5.5vw, 5.5rem);
    color: var(--ink);
    line-height: 1;
    margin-bottom: 2rem;
    letter-spacing: -0.04em;
    transition: color 0.4s;
  }
  .grade-card:hover .grade-code { color: var(--gold); }
  .grade-tier {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 300;
    font-size: 1.15rem;
    color: var(--ink-2);
    margin-bottom: 0.8rem;
  }
  .grade-name {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 0.98rem;
    color: var(--ink-dim);
    margin-bottom: 2.5rem;
    line-height: 1.5;
  }
  .grade-bottom {
    display: flex;
    flex-direction: column;
  }
  .grade-specs {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.9rem;
    border-top: 1px solid var(--rule-2);
    padding-top: 1.75rem;
    transition: border-color 0.4s;
  }
  .grade-card:hover .grade-specs { border-top-color: var(--gold-deep); }
  .grade-specs li {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 1rem;
  }
  .spec-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }
  .spec-value {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 0.95rem;
    color: var(--ink);
    letter-spacing: -0.01em;
  }
  .spec-value .unit {
    color: var(--ink-dim);
    font-weight: 300;
    font-size: 0.8em;
    margin-left: 0.3rem;
  }
  .grade-applications {
    margin-top: 2rem;
    padding: 1.5rem;
    border: 1px solid rgba(201, 169, 97, 0.25);
    background: rgba(201, 169, 97, 0.06);
    font-size: 1.15rem;
    color: var(--ink);
    line-height: 1.55;
    font-style: normal;
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    transition: border-color 0.4s, background 0.4s;
  }
  .grade-card:hover .grade-applications {
    border-color: var(--gold-deep);
    background: rgba(201, 169, 97, 0.1);
  }

  .grades-note {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin-top: 2.5rem;
    margin-left: -2.5rem;
    margin-right: -2.5rem;
    padding: 2rem 4rem;
    border: 1px solid var(--gold-deep);
    background: rgba(201, 169, 97, 0.08);
  }
  .grades-note-bar {
    flex-shrink: 0;
    width: 36px;
    height: 2px;
    background: var(--gold);
  }
  .grades-note-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-weight: 600;
    color: var(--gold-light);
    text-align: center;
    flex: 1;
  }

  /* ============ STAT HIGHLIGHT — refined ============ */
  .stat-highlight {
    padding: 12rem 2.5rem;
    background: var(--black);
    position: relative;
    overflow: hidden;
    text-align: center;
  }
  .stat-highlight::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 50% 80% at 50% 50%, var(--gold-glow) 0%, transparent 60%);
    pointer-events: none;
  }
  .stat-highlight-content {
    position: relative;
    z-index: 2;
    max-width: 1000px;
    margin: 0 auto;
  }
  .stat-eyebrow {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.7rem;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--gold);
    margin-bottom: 3rem;
    opacity: 0;
  }
  .stat-number {
    font-family: 'Inter', sans-serif;
    font-size: clamp(6rem, 16vw, 14rem);
    font-weight: 400;
    color: var(--gold);
    line-height: 0.9;
    letter-spacing: -0.05em;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
  }
  .stat-number em {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 500;
  }
  .stat-caption {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: clamp(1.25rem, 2vw, 1.65rem);
    color: var(--ink-2);
    max-width: 32ch;
    margin: 0 auto 3rem;
    line-height: 1.4;
    letter-spacing: -0.005em;
  }
  .stat-caption em {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    color: var(--ink);
  }
  .stat-source {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.68rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }

  /* ============ PERFORMANCE CHART ============ */
  .performance {
    background: var(--black-2);
    border-top: 1px solid var(--rule-2);
    border-bottom: 1px solid var(--rule-2);
  }
  .friction-callout {
    margin-top: 4rem;
    background: var(--black-3);
    border: 1px solid var(--rule-2);
    border-left: 3px solid var(--gold);
    padding: 2.5rem 3rem;
  }
  .friction-callout-lead {
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    font-size: 1.2rem;
    line-height: 1.55;
    color: var(--ink);
    letter-spacing: -0.005em;
    margin: 0 0 1.75rem;
  }
  .friction-callout-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.9rem;
  }
  .friction-callout-list li {
    position: relative;
    padding-left: 1.5rem;
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 1.02rem;
    line-height: 1.6;
    color: var(--ink-2);
  }
  .friction-callout-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.7rem;
    width: 6px; height: 6px;
    background: var(--gold);
    border-radius: 50%;
  }
  .friction-callout-list li em {
    font-style: normal;
    font-weight: 600;
    color: var(--gold);
  }
  .chart-wrapper {
    background: var(--black-3);
    border: 1px solid var(--rule-2);
    padding: 3rem;
    margin-top: 4rem;
    position: relative;
  }
  .chart-meta {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--rule-2);
  }
  .chart-title {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 1.15rem;
    color: var(--ink);
    letter-spacing: -0.01em;
  }
  .chart-title em {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 500;
    color: var(--gold);
    margin-left: 0.3rem;
  }
  .chart-source {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }
  .chart-svg {
    width: 100%;
    height: auto;
    display: block;
  }
  .chart-legend {
    display: flex;
    gap: 2.5rem;
    flex-wrap: wrap;
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--rule-2);
  }
  .legend-item {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    font-family: 'Inter', sans-serif;
    font-size: 0.82rem;
    color: var(--ink-2);
    font-weight: 300;
  }
  .legend-swatch {
    width: 28px; height: 2px;
  }

  .takeaways {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    background: var(--rule-2);
    margin-top: 3rem;
    border: 1px solid var(--rule-2);
  }
  .takeaway {
    background: var(--black-2);
    padding: 2.5rem;
  }
  .takeaway-num {
    font-family: 'Inter', sans-serif;
    font-weight: 200;
    font-size: 3rem;
    color: var(--gold);
    line-height: 1;
    margin-bottom: 1rem;
    letter-spacing: -0.04em;
  }
  .takeaway-num em {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 500;
  }
  .takeaway-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    margin-bottom: 1rem;
  }
  .takeaway-desc {
    color: var(--ink-2);
    font-size: 0.92rem;
    line-height: 1.6;
    font-weight: 300;
  }

  /* ============ VIDEO SECTION ============ */
  .video-section {
    background: var(--black);
    border-bottom: 1px solid var(--rule-2);
  }
  .video-frame {
    position: relative;
    aspect-ratio: 16/9;
    background: var(--black-3);
    border: 1px solid var(--rule-2);
    overflow: hidden;
    margin-top: 4rem;
  }
  .video-frame video {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: cover;
  }
  .video-play-btn {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    width: 88px; height: 88px;
    border: 1px solid var(--gold);
    background: rgba(11, 11, 13, 0.6);
    backdrop-filter: blur(12px);
    color: var(--gold);
    cursor: pointer;
    transition: all 0.4s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    z-index: 5;
  }
  .video-play-btn:hover {
    background: var(--gold);
    color: var(--black);
    transform: translate(-50%, -50%) scale(1.08);
  }
  .video-play-btn.hidden { opacity: 0; pointer-events: none; }
  .video-play-btn svg { width: 26px; height: 26px; margin-left: 3px; }
  .video-caption {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--rule-2);
  }
  .video-caption span {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }

  /* ============ CALCULATOR ============ */
  .calculator {
    background: var(--black-2);
    border-bottom: 1px solid var(--rule-2);
  }
  .calc-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    margin-top: 4rem;
  }
  .calc-inputs, .calc-results {
    background: var(--black-3);
    border: 1px solid var(--rule-2);
    padding: 3rem;
  }
  .calc-inputs-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    column-gap: 3rem;
    row-gap: 2.25rem;
  }
  .calc-inputs-grid .calc-row { margin-bottom: 0; }
  @media (max-width: 720px) {
    .calc-inputs-grid { grid-template-columns: 1fr; }
  }
  .calc-panel-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.68rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    margin-bottom: 2.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--rule-2);
  }
  .calc-row {
    margin-bottom: 2rem;
  }
  .calc-row:last-child { margin-bottom: 0; }
  .calc-label {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 1rem;
  }
  .calc-label-text {
    font-family: 'Inter', sans-serif;
    font-size: 0.88rem;
    color: var(--ink-2);
    font-weight: 300;
  }
  .calc-value {
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 1.15rem;
    color: var(--gold);
    letter-spacing: -0.01em;
  }
  input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 2px;
    background: var(--rule);
    outline: none;
    border-radius: 2px;
  }
  input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px; height: 14px;
    background: var(--gold);
    cursor: pointer;
    border-radius: 50%;
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: 0 0 0 4px rgba(201, 169, 97, 0.1);
  }
  input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 0 8px rgba(201, 169, 97, 0.15);
  }
  input[type="range"]::-moz-range-thumb {
    width: 14px; height: 14px;
    background: var(--gold);
    cursor: pointer;
    border: none;
    border-radius: 50%;
  }

  .grade-select {
    display: flex;
    gap: 0.5rem;
  }
  .grade-select button {
    flex: 1;
    padding: 0.9rem;
    background: transparent;
    border: 1px solid var(--rule);
    color: var(--ink-2);
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    font-size: 0.88rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 2px;
    letter-spacing: -0.005em;
  }
  .grade-select button:hover {
    border-color: var(--gold);
    color: var(--gold);
  }
  .grade-select button.active {
    background: var(--gold);
    color: var(--black);
    border-color: var(--gold);
  }

  .calc-main-metric {
    margin-bottom: 3rem;
  }
  .calc-main-metric .label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    margin-bottom: 1.2rem;
  }
  .calc-main-metric .value {
    font-family: 'Inter', sans-serif;
    font-weight: 200;
    font-size: clamp(2.75rem, 4.5vw, 4rem);
    color: var(--gold);
    line-height: 1;
    letter-spacing: -0.04em;
  }
  .calc-secondary {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--rule-2);
  }
  .calc-secondary .metric { }
  .calc-secondary .metric .val {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    font-size: 1.6rem;
    color: var(--ink);
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
  }
  .calc-secondary .metric .lbl {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }
  .calc-disclaimer {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 300;
    font-size: 0.82rem;
    color: var(--ink-dim);
    margin-top: 2.5rem;
    line-height: 1.6;
    padding-top: 1.5rem;
    border-top: 1px solid var(--rule-2);
  }

  /* ============ APPLICATIONS ============ */
  .applications {
    background: var(--black);
  }
  .apps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    background: var(--rule-2);
    margin-top: 4rem;
    border: 1px solid var(--rule-2);
  }
  .app-card {
    background: var(--black);
    padding: 3rem 2.5rem;
    transition: background 0.4s ease;
    cursor: default;
  }
  .app-card:hover { background: var(--black-2); }
  .app-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    color: var(--gold);
    margin-bottom: 2rem;
  }
  .app-title {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--ink);
    letter-spacing: -0.025em;
  }
  .app-desc {
    color: var(--ink-2);
    line-height: 1.65;
    margin-bottom: 2rem;
    font-size: 0.95rem;
    font-weight: 300;
  }
  .app-specs {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    border-top: 1px solid var(--rule-2);
    padding-top: 1.5rem;
  }
  .app-specs li {
    display: flex;
    justify-content: space-between;
    font-family: 'Inter', sans-serif;
    font-size: 0.82rem;
  }
  .app-specs .k {
    color: var(--ink-dim);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    font-weight: 400;
  }
  .app-specs .v {
    color: var(--ink);
    text-align: right;
    font-weight: 300;
  }
  .app-grid-img {
    grid-column: span 2;
    overflow: hidden;
    background: var(--black);
    min-height: 320px;
    position: relative;
  }
  .app-grid-img-wide {
    grid-column: 1 / -1;
    min-height: 400px;
    max-height: 440px;
  }
  .app-grid-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: block;
    image-rendering: high-quality;
    transition: transform 1.4s cubic-bezier(0.2, 0.6, 0.2, 1);
  }
  .app-grid-img-wide:hover img {
    transform: scale(1.025);
  }
  .app-grid-img::after {
    content: '';
    position: absolute;
    inset: 0;
    background:
      linear-gradient(to right,  rgba(8,8,8,0.72) 0%, transparent 35%),
      linear-gradient(to left,   rgba(8,8,8,0.72) 0%, transparent 35%),
      linear-gradient(to bottom, rgba(8,8,8,0.55) 0%, transparent 40%),
      linear-gradient(to top,    rgba(8,8,8,0.72) 0%, transparent 40%);
    pointer-events: none;
  }
  /* Mono eyebrow caption sitting on the image */
  .app-grid-img-eyebrow {
    position: absolute;
    left: 2rem;
    bottom: 2rem;
    z-index: 2;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.24em;
    text-transform: uppercase;
    color: var(--gold);
    padding-left: 1rem;
    border-left: 1px solid var(--gold-deep);
  }

  /* ============ TUBING FEATURE LAYOUT ============ */
  .tubing-feature {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1px;
    background: var(--rule-2);
    margin-top: 4rem;
    border: 1px solid var(--rule-2);
  }
  .tubing-feature-specs {
    background: var(--black);
    padding: 4rem 3.5rem;
  }
  .tubing-feature-highlights {
    background: var(--black-2);
    padding: 4rem 3.5rem;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
  }
  /* Scoped size bumps for the tubing feature section */
  .tubing-feature .app-num        { font-size: 0.78rem; }
  .tubing-feature .app-title      { font-size: 2.5rem; }
  .tubing-feature .app-desc       { font-size: 1.1rem; line-height: 1.7; }
  .tubing-feature .app-specs li   { font-size: 0.98rem; }
  .tubing-feature .app-specs .k   { font-size: 0.75rem; }
  .tubing-feature .app-specs .v   { font-size: 0.98rem; }
  .tubing-grades {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    justify-content: flex-end;
  }
  .tubing-grade-pill {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    letter-spacing: 0.1em;
    color: var(--gold);
    border: 1px solid rgba(201,169,97,0.28);
    padding: 0.25rem 0.7rem;
    border-radius: 2px;
  }
  .tubing-highlights {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 1.4rem;
    margin-top: 0;
  }
  .tubing-highlights li {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    font-size: 1.1rem;
    color: var(--ink-2);
    font-weight: 300;
    line-height: 1.65;
  }
  .tubing-highlights li::before {
    content: '—';
    color: var(--gold);
    flex-shrink: 0;
    font-family: 'JetBrains Mono', monospace;
  }
  .tubing-coverage {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.78rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--gold);
    padding-top: 2rem;
    border-top: 1px solid var(--rule-2);
    margin-top: 2.5rem;
  }

  /* ============ CONTACT ============ */
  .contact {
    background: var(--black-2);
    border-top: 1px solid var(--rule-2);
  }
  .contact-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6rem;
  }
  .contact-info .section-title { margin-bottom: 2rem; }
  .contact-info p {
    color: var(--ink-2);
    line-height: 1.65;
    margin-bottom: 3.5rem;
    font-weight: 300;
    max-width: 44ch;
  }
  .contact-meta {
    display: flex;
    flex-direction: column;
    gap: 1.75rem;
  }
  .contact-meta-item {
    display: grid;
    grid-template-columns: 110px 1fr;
    gap: 1.5rem;
    padding-bottom: 1.75rem;
    border-bottom: 1px solid var(--rule-2);
    align-items: start;
  }
  .contact-meta-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    padding-top: 0.25rem;
  }
  .contact-meta-val {
    color: var(--ink);
    font-size: 1rem;
    font-weight: 300;
  }
  .contact-meta-val a {
    color: var(--ink);
    text-decoration: none;
    transition: color 0.3s;
    border-bottom: 1px solid var(--rule);
  }
  .contact-meta-val a:hover {
    color: var(--gold);
    border-bottom-color: var(--gold);
  }

  .contact-form {
    background: var(--black-3);
    border: 1px solid var(--rule-2);
    padding: 3.5rem;
  }
  .form-row { margin-bottom: 1.75rem; }
  .form-row.two {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }
  .form-label {
    display: block;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
    margin-bottom: 0.8rem;
    font-weight: 400;
  }
  .form-label .req { color: var(--gold); }
  .form-input, .form-select, .form-textarea {
    width: 100%;
    background: transparent;
    border: none;
    border-bottom: 1px solid var(--rule);
    color: var(--ink);
    padding: 0.8rem 0;
    font-family: 'Inter', sans-serif;
    font-size: 0.98rem;
    font-weight: 300;
    transition: border-color 0.3s;
    letter-spacing: -0.005em;
  }
  .form-input:focus, .form-select:focus, .form-textarea:focus {
    outline: none;
    border-bottom-color: var(--gold);
  }
  .form-textarea {
    min-height: 100px;
    resize: vertical;
    line-height: 1.6;
  }
  .form-select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'><path fill='%23c9a961' d='M6 8L0 0h12z'/></svg>");
    background-repeat: no-repeat;
    background-position: right 0.25rem center;
    padding-right: 2rem;
  }
  .form-submit {
    width: 100%;
    background: var(--gold);
    color: var(--black);
    border: none;
    padding: 1.2rem;
    font-family: 'Inter', sans-serif;
    font-size: 0.88rem;
    font-weight: 500;
    letter-spacing: 0.01em;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 2rem;
    border-radius: 100px;
  }
  .form-submit:hover {
    background: var(--gold-light);
    transform: translateY(-1px);
    box-shadow: 0 12px 32px -12px rgba(201, 169, 97, 0.5);
  }
  .form-note {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 300;
    font-size: 0.78rem;
    color: var(--ink-dim);
    margin-top: 1.5rem;
    line-height: 1.6;
  }
  .form-success { display: none; text-align: center; padding: 2rem 0; }
  .form-success.show { display: block; }
  .form-success .check {
    width: 50px; height: 50px;
    margin: 0 auto 2rem;
    border: 1px solid var(--gold);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--gold);
    font-size: 1.5rem;
  }
  .form-success h3 {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    font-size: 1.5rem;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
  }
  .form-success p { color: var(--ink-2); font-weight: 300; }

  /* ============ FOOTER ============ */
  footer {
    background: var(--black);
    border-top: 1px solid var(--rule-2);
    padding: 5rem 2.5rem 2.5rem;
  }
  .footer-content {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 4rem;
    margin-bottom: 4rem;
  }
  .footer-brand {
    max-width: 42ch;
  }
  .footer-brand-logo {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    font-size: 1.5rem;
    line-height: 1.15;
    margin-bottom: 2rem;
    letter-spacing: -0.02em;
  }
  .footer-brand-logo em {
    font-family: 'Inter', sans-serif;
    font-style: normal;
    font-weight: 500;
    color: var(--gold);
  }
  .footer-tag {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.68rem;
    letter-spacing: 0.24em;
    color: var(--gold);
    text-transform: uppercase;
    margin-bottom: 1.5rem;
  }
  .footer-desc {
    color: var(--ink-dim);
    line-height: 1.65;
    font-size: 0.88rem;
    font-weight: 300;
  }
  .footer-col h4 {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink);
    margin-bottom: 1.5rem;
    font-weight: 400;
  }
  .footer-col ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
  }
  .footer-col a {
    color: var(--ink-dim);
    text-decoration: none;
    font-size: 0.88rem;
    font-weight: 300;
    transition: color 0.3s;
  }
  .footer-col a:hover { color: var(--gold); }
  .footer-bottom {
    max-width: 1400px;
    margin: 0 auto;
    border-top: 1px solid var(--rule-2);
    padding-top: 2rem;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
  }
  .footer-bottom p {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    color: var(--ink-faint);
    letter-spacing: 0.18em;
    text-transform: uppercase;
  }

  /* ============ COST ADVANTAGES ============ */
  .cost-advantages {
    margin-bottom: 5rem;
  }
  .cost-advantages-header {
    margin-bottom: 2.5rem;
  }
  .cost-note {
    padding: 3rem 3.25rem;
    border: 1px solid rgba(201, 169, 97, 0.25);
    background: rgba(201, 169, 97, 0.05);
    position: relative;
  }
  .cost-note::before {
    content: '';
    position: absolute;
    left: 0;
    top: 12%;
    bottom: 12%;
    width: 3px;
    background: var(--gold);
  }
  .cost-note p {
    font-family: 'Inter', sans-serif;
    font-size: 1.2rem;
    font-weight: 400;
    line-height: 1.65;
    color: var(--ink-2);
    letter-spacing: -0.005em;
    margin: 0 0 1.1rem 0;
  }
  .cost-note p:last-child { margin-bottom: 0; }
  .cost-note .cost-note-lead {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: 1.65rem;
    color: var(--ink);
    letter-spacing: -0.015em;
    margin-bottom: 1.4rem;
  }
  .cost-note .cost-note-tail {
    margin-top: 1.4rem;
    padding-top: 1.4rem;
    border-top: 1px solid rgba(201, 169, 97, 0.18);
    font-weight: 500;
    color: var(--ink);
    font-size: 1.25rem;
  }
  .cost-note em {
    font-style: normal;
    font-weight: 600;
    color: var(--gold);
  }
  .cost-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1px;
    background: var(--rule-2);
    border: 1px solid var(--rule-2);
  }
  .cost-card {
    background: var(--black-3);
    padding: 2.75rem 2.5rem;
    transition: background 0.4s ease;
  }
  .cost-card:hover { background: var(--black-4); }
  .cost-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    color: var(--gold);
    margin-bottom: 1.25rem;
  }
  .cost-title {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: 1.05rem;
    color: var(--ink);
    letter-spacing: -0.01em;
    margin-bottom: 0.85rem;
  }
  .cost-desc {
    font-family: 'Inter', sans-serif;
    font-size: 0.92rem;
    color: var(--ink-2);
    line-height: 1.65;
    font-weight: 300;
  }
  .calc-section-header {
    margin-bottom: 2rem;
    padding-top: 4rem;
    border-top: 1px solid var(--rule-2);
  }
  @media (max-width: 720px) {
    .cost-grid { grid-template-columns: 1fr; }
  }

  /* ============ CALCULATOR UX ENHANCEMENTS ============ */
  .service-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.6rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--gold);
    margin-top: 0.55rem;
  }
  .view-toggle {
    display: flex;
    width: fit-content;
    border: 1px solid var(--rule);
    border-radius: 100px;
    overflow: hidden;
    margin-bottom: 2rem;
  }
  .toggle-btn {
    background: transparent;
    border: none;
    color: var(--ink-dim);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.6rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    padding: 0.55rem 1.25rem;
    cursor: pointer;
    transition: all 0.25s ease;
  }
  .toggle-btn.active {
    background: var(--gold);
    color: var(--black);
  }
  .toggle-btn:hover:not(.active) { color: var(--gold); }
  .calc-breakdown {
    margin-bottom: 1.75rem;
  }
  .breakdown-row {
    padding: 0.9rem 0;
    border-bottom: 1px solid var(--rule-2);
  }
  .breakdown-row-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 1rem;
  }
  .breakdown-label {
    font-family: 'Inter', sans-serif;
    font-size: 0.88rem;
    color: var(--ink-2);
    font-weight: 300;
  }
  .breakdown-value {
    font-family: 'Inter', sans-serif;
    font-size: 1.05rem;
    font-weight: 400;
    color: var(--ink);
    letter-spacing: -0.01em;
    white-space: nowrap;
  }
  .breakdown-value-negative { color: #e05252; }
  .breakdown-sub {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.58rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--ink-faint);
    margin-top: 0.3rem;
  }
  .breakdown-divider {
    height: 1px;
    background: rgba(255,255,255,0.12);
    margin: 0.25rem 0;
  }
  .breakdown-total {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    padding: 1.1rem 0 0.25rem;
  }
  .breakdown-total-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-dim);
  }
  .breakdown-total-value {
    font-family: 'Inter', sans-serif;
    font-weight: 200;
    font-size: clamp(2rem, 3.5vw, 3rem);
    color: var(--gold);
    letter-spacing: -0.04em;
    line-height: 1;
  }
  .breakdown-total.is-negative .breakdown-total-value { color: #e05252; }
  .roi-badge {
    display: inline-block;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.63rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--gold);
    border: 1px solid var(--gold-deep);
    background: var(--gold-glow);
    padding: 0.5rem 1rem;
    margin-bottom: 2rem;
  }

  /* ===== Side-by-side grade comparison table ===== */
  .calc-results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--rule-2);
  }
  .calc-results-header .calc-panel-title {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
  }
  .calc-results-header .view-toggle { margin-bottom: 0; }

  .results-table {
    display: grid;
    grid-template-columns: minmax(180px, 1.5fr) repeat(3, minmax(140px, 1fr));
    margin-bottom: 1.75rem;
  }
  .results-th {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.62rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--gold);
    text-align: right;
    padding: 0.5rem 1rem 1.4rem;
    border-bottom: 1px solid var(--rule);
  }
  .results-th-corner {
    border-bottom: 1px solid var(--rule);
    padding-left: 0;
  }
  .results-rowlabel {
    padding: 1.4rem 1.25rem 1.4rem 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    border-bottom: 1px solid var(--rule-2);
  }
  .rl-main {
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem;
    color: var(--ink-2);
    font-weight: 300;
    line-height: 1.3;
  }
  .rl-sub {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.55rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--ink-faint);
    margin-top: 0.45rem;
  }
  .results-cell {
    padding: 1.4rem 1rem;
    text-align: right;
    font-family: 'Inter', sans-serif;
    font-size: 1.05rem;
    font-weight: 400;
    color: var(--ink);
    letter-spacing: -0.01em;
    border-bottom: 1px solid var(--rule-2);
    white-space: nowrap;
    align-self: center;
  }

  /* Featured "Net Lifetime Savings" row */
  .results-rowlabel-feature .rl-main {
    color: var(--ink);
    font-weight: 400;
    font-size: 1rem;
  }
  .results-rowlabel-feature { padding-top: 2rem; padding-bottom: 2rem; }
  .results-cell-total {
    font-weight: 200;
    font-size: clamp(1.45rem, 2.2vw, 2rem);
    color: var(--gold);
    letter-spacing: -0.03em;
    line-height: 1.1;
    padding-top: 2rem;
    padding-bottom: 2rem;
  }
  .results-cell-total.is-negative { color: #e05252; }

  /* Runtime cell: months on top, years below */
  .results-cell-runtime .runtime-mo {
    display: block;
    color: var(--ink);
    font-size: 1.05rem;
  }
  .results-cell-runtime .runtime-yr {
    display: block;
    color: var(--ink-faint);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.6rem;
    letter-spacing: 0.14em;
    margin-top: 0.4rem;
    text-transform: uppercase;
  }

  .results-cell-neg { color: #e05252; }

  /* Last 4 cells in the grid (last row) — no bottom border */
  .results-table > *:nth-last-child(-n+4) { border-bottom: none; }

  /* Responsive: under 720px the 4-col table becomes 3 stacked grade cards */
  @media (max-width: 720px) {
    .results-table {
      grid-template-columns: 1fr;
      gap: 1.25rem;
    }
    .results-th-corner { display: none; }
    .results-th {
      text-align: left;
      padding: 1rem 0 0.5rem;
      border-bottom: 1px solid var(--rule);
      font-size: 0.7rem;
      color: var(--gold);
    }
    .results-rowlabel,
    .results-cell {
      padding: 0.75rem 0;
      border-bottom: 1px solid var(--rule-2);
      text-align: left;
    }
    .results-rowlabel { padding-top: 1.25rem; }
    .results-cell-total { padding: 0.75rem 0; font-size: 1.6rem; }
    .results-rowlabel-feature { padding-top: 1.25rem; padding-bottom: 0.5rem; }
    .results-table > *:nth-last-child(-n+4) { border-bottom: 1px solid var(--rule-2); }
    .results-table > *:last-child { border-bottom: none; }
  }

  /* ============ REVEAL STATES ============ */
  .fade-in {
    opacity: 0;
    transform: translateY(24px);
  }

  /* ============ RESPONSIVE ============ */
  @media (max-width: 1024px) {
    .science-layout { grid-template-columns: 1fr; gap: 4rem; }
    .grades-track { grid-template-columns: 1fr; }
    .apps-grid { grid-template-columns: 1fr; }
    .tubing-feature { grid-template-columns: 1fr; }
    .app-grid-img { grid-column: span 1; min-height: 220px; }
    .app-grid-img-wide { min-height: 280px; max-height: 320px; }
    .takeaways { grid-template-columns: 1fr; }
    .calc-layout { grid-template-columns: 1fr; }
    .contact-layout { grid-template-columns: 1fr; gap: 4rem; }
    .footer-content { grid-template-columns: 1fr 1fr; gap: 3rem; }
    .hero-metrics { grid-template-columns: repeat(2, 1fr); gap: 2rem; }
  }
  @media (max-width: 720px) {
    .hero h1 { white-space: normal; }
    nav { padding: 1rem 1.5rem; }
    .nav-links { display: none; }
    .nav-toggle { display: block; }
    .nav-links.mobile-open {
      display: flex;
      position: absolute;
      top: 100%; left: 0; right: 0;
      flex-direction: column;
      background: var(--black);
      padding: 2rem 1.5rem;
      gap: 1.5rem;
      border-bottom: 1px solid var(--rule-2);
    }
    section { padding: 6rem 1.5rem; }
    .hero { padding: 7rem 1.5rem 10rem; }
    .hero-bg-img { width: 120%; right: -30%; opacity: 0.35; }
    .hero-metrics {
      grid-template-columns: 1fr 1fr;
      margin-top: 3.5rem;
      gap: 2rem;
    }
    .form-row.two { grid-template-columns: 1fr; }
    .contact-form { padding: 2rem 1.5rem; }
    .calc-inputs, .calc-results { padding: 2rem 1.5rem; }
    .chart-wrapper { padding: 1.5rem; }
    .grade-card { padding: 2.5rem 2rem; }
    .footer-content { grid-template-columns: 1fr; gap: 2rem; }
    .problem { padding: 8rem 1.5rem; }
    .stat-highlight { padding: 8rem 1.5rem; }
  }