/* ============================================================
   LADAR — Low Atmospheric Data Acquisition and Research
   Main Stylesheet
   ============================================================ */

   @import url('https://fonts.googleapis.com/css2?family=Syne:wght@400;500;600;700;800&family=DM+Mono:ital,wght@0,300;0,400;0,500;1,300&family=Lora:ital,wght@0,400;0,500;1,400&display=swap');

   /* ── Variables ─────────────────────────────────────────────── */
   :root {
     --bg:           #080c12;
     --bg-2:         #0d1420;
     --bg-3:         #111b2e;
     --surface:      #0f1a2e;
     --border:       rgba(100, 180, 220, 0.12);
     --border-bright:rgba(100, 180, 220, 0.28);
   
     --accent:       #3ec9e0;
     --accent-dim:   rgba(62, 201, 224, 0.15);
     --accent-glow:  rgba(62, 201, 224, 0.06);
     --amber:        #e0a53e;
     --amber-dim:    rgba(224, 165, 62, 0.12);
     --red:          #e05a3e;
   
     --text:         #d6e8f0;
     --text-muted:   #6a8fa8;
     --text-faint:   #364f62;
     --white:        #f0f8ff;
   
     --font-display: 'Syne', sans-serif;
     --font-mono:    'DM Mono', monospace;
     --font-body:    'Lora', serif;
   
     --radius:       4px;
     --radius-lg:    8px;
     --transition:   0.22s ease;
     --nav-h:        68px;
   }
   
   /* ── Reset & Base ──────────────────────────────────────────── */
   *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
   
   html { scroll-behavior: smooth; font-size: 16px; }
   
   body {
     background-color: var(--bg);
     color: var(--text);
     font-family: var(--font-body);
     line-height: 1.7;
     min-height: 100vh;
     overflow-x: hidden;
   }
   
   img { display: block; max-width: 100%; }
   a  { color: inherit; text-decoration: none; }
   ul { list-style: none; }
   
   /* ── Scrollbar ─────────────────────────────────────────────── */
   ::-webkit-scrollbar              { width: 6px; }
   ::-webkit-scrollbar-track        { background: var(--bg); }
   ::-webkit-scrollbar-thumb        { background: var(--border-bright); border-radius: 3px; }
   ::-webkit-scrollbar-thumb:hover  { background: var(--accent); }
   
   /* ── Selection ─────────────────────────────────────────────── */
   ::selection { background: var(--accent-dim); color: var(--accent); }
   
   /* ============================================================
      NAVIGATION
      ============================================================ */
   .nav {
     position: fixed;
     top: 0; left: 0; right: 0;
     height: var(--nav-h);
     z-index: 1000;
     display: flex;
     align-items: center;
     justify-content: space-between;
     padding: 0 3rem;
     background: rgba(8, 12, 18, 0.72);
     backdrop-filter: blur(18px);
     -webkit-backdrop-filter: blur(18px);
     border-bottom: 1px solid var(--border);
     transition: background var(--transition), border-color var(--transition);
   }
   
   .nav.scrolled {
     background: rgba(8, 12, 18, 0.92);
     border-bottom-color: var(--border-bright);
   }
   
   .nav-logo {
     display: flex;
     flex-direction: column;
     gap: 1px;
   }
   
   .nav-logo-primary {
     font-family: var(--font-display);
     font-weight: 800;
     font-size: 1.1rem;
     letter-spacing: 0.14em;
     color: var(--accent);
     line-height: 1;
   }
   
   .nav-logo-sub {
     font-family: var(--font-mono);
     font-size: 0.58rem;
     letter-spacing: 0.06em;
     color: var(--text-muted);
     line-height: 1;
   }
   
   .nav-links {
     display: flex;
     align-items: center;
     gap: 2.4rem;
   }
   
   .nav-links a {
     font-family: var(--font-display);
     font-size: 0.78rem;
     font-weight: 500;
     letter-spacing: 0.1em;
     text-transform: uppercase;
     color: var(--text-muted);
     transition: color var(--transition);
     position: relative;
   }
   
   .nav-links a::after {
     content: '';
     position: absolute;
     bottom: -4px; left: 0; right: 0;
     height: 1px;
     background: var(--accent);
     transform: scaleX(0);
     transform-origin: left;
     transition: transform var(--transition);
   }
   
   .nav-links a:hover,
   .nav-links a.active {
     color: var(--accent);
   }
   
   .nav-links a:hover::after,
   .nav-links a.active::after {
     transform: scaleX(1);
   }
   
   .nav-toggle {
     display: none;
     flex-direction: column;
     justify-content: center;
     gap: 5px;
     cursor: pointer;
     padding: 10px 8px;
     background: none;
     border: none;
     min-width: 44px;
     min-height: 44px;
     align-items: center;
   }
   
   .nav-toggle span {
     display: block;
     width: 22px;
     height: 2px;
     background: var(--text-muted);
     border-radius: 2px;
     transition: transform var(--transition), opacity var(--transition), background var(--transition);
     transform-origin: center;
   }
   
   /* Animated X when open */
   .nav-toggle[aria-expanded="true"] span:nth-child(1) {
     transform: translateY(7px) rotate(45deg);
     background: var(--accent);
   }
   .nav-toggle[aria-expanded="true"] span:nth-child(2) {
     opacity: 0;
     transform: scaleX(0);
   }
   .nav-toggle[aria-expanded="true"] span:nth-child(3) {
     transform: translateY(-7px) rotate(-45deg);
     background: var(--accent);
   }
   
   /* ============================================================
      HERO
      ============================================================ */
   .hero {
     min-height: 100vh;
     display: flex;
     flex-direction: column;
     justify-content: center;
     padding: calc(var(--nav-h) + 4rem) 3rem 4rem;
     position: relative;
     overflow: hidden;
   }
   
   .hero-grid-bg {
     position: absolute;
     inset: 0;
     background-image:
       linear-gradient(rgba(62, 201, 224, 0.035) 1px, transparent 1px),
       linear-gradient(90deg, rgba(62, 201, 224, 0.035) 1px, transparent 1px);
     background-size: 48px 48px;
     mask-image: radial-gradient(ellipse 80% 80% at 50% 40%, black 30%, transparent 100%);
   }
   
   .hero-glow {
     position: absolute;
     top: 20%;
     left: 50%;
     transform: translateX(-50%);
     width: 600px;
     height: 400px;
     background: radial-gradient(ellipse, rgba(62, 201, 224, 0.07) 0%, transparent 70%);
     pointer-events: none;
   }
   
   .hero-content {
     position: relative;
     max-width: 900px;
   }
   
   .hero-tag {
     font-family: var(--font-mono);
     font-size: 0.7rem;
     letter-spacing: 0.16em;
     text-transform: uppercase;
     color: var(--accent);
     display: inline-flex;
     align-items: center;
     gap: 0.6rem;
     margin-bottom: 2rem;
     opacity: 0;
     animation: fadeUp 0.7s ease 0.2s forwards;
   }
   
   .hero-tag::before {
     content: '';
     display: block;
     width: 28px;
     height: 1px;
     background: var(--accent);
   }
   
   .hero-title {
     font-family: var(--font-display);
     font-weight: 800;
     font-size: clamp(2.8rem, 7vw, 6rem);
     line-height: 1.0;
     letter-spacing: -0.02em;
     color: var(--white);
     margin-bottom: 0.4rem;
     opacity: 0;
     animation: fadeUp 0.7s ease 0.35s forwards;
   }
   
   .hero-title span {
     color: var(--accent);
   }
   
   .hero-subtitle {
     font-family: var(--font-display);
     font-weight: 400;
     font-size: clamp(1rem, 2.2vw, 1.4rem);
     letter-spacing: 0.04em;
     color: var(--text-muted);
     margin-bottom: 2.4rem;
     opacity: 0;
     animation: fadeUp 0.7s ease 0.45s forwards;
   }
   
   .hero-description {
     font-family: var(--font-body);
     font-size: 1.05rem;
     color: var(--text);
     max-width: 640px;
     line-height: 1.8;
     margin-bottom: 3rem;
     opacity: 0;
     animation: fadeUp 0.7s ease 0.55s forwards;
   }
   
   .hero-cta {
     display: flex;
     gap: 1rem;
     flex-wrap: wrap;
     opacity: 0;
     animation: fadeUp 0.7s ease 0.65s forwards;
   }
   
   .hero-scroll {
     position: absolute;
     bottom: 2.5rem;
     left: 3rem;
     display: flex;
     align-items: center;
     gap: 0.8rem;
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.12em;
     text-transform: uppercase;
     color: var(--text-faint);
     opacity: 0;
     animation: fadeIn 1s ease 1.2s forwards;
   }
   
   .hero-scroll-line {
     width: 1px;
     height: 48px;
     background: linear-gradient(to bottom, var(--accent), transparent);
     animation: scrollPulse 2s ease infinite;
   }
   
   /* ============================================================
      BUTTONS
      ============================================================ */
   .btn {
     display: inline-flex;
     align-items: center;
     gap: 0.5rem;
     padding: 0.75rem 1.8rem;
     font-family: var(--font-display);
     font-size: 0.78rem;
     font-weight: 600;
     letter-spacing: 0.1em;
     text-transform: uppercase;
     border-radius: var(--radius);
     cursor: pointer;
     transition: all var(--transition);
     border: 1px solid transparent;
     white-space: nowrap;
   }
   
   .btn-primary {
     background: var(--accent);
     color: var(--bg);
     border-color: var(--accent);
   }
   
   .btn-primary:hover {
     background: transparent;
     color: var(--accent);
     box-shadow: 0 0 24px rgba(62, 201, 224, 0.2);
   }
   
   .btn-outline {
     background: transparent;
     color: var(--text);
     border-color: var(--border-bright);
   }
   
   .btn-outline:hover {
     border-color: var(--accent);
     color: var(--accent);
     background: var(--accent-glow);
   }
   
   .btn-sm {
     padding: 0.5rem 1.2rem;
     font-size: 0.72rem;
   }
   
   /* ============================================================
      LAYOUT & CONTAINERS
      ============================================================ */
   .container {
     max-width: 1180px;
     margin: 0 auto;
     padding: 0 3rem;
   }
   
   .section {
     padding: 7rem 0;
   }
   
   .section-sm {
     padding: 4rem 0;
   }
   
   .section-tag {
     font-family: var(--font-mono);
     font-size: 0.68rem;
     letter-spacing: 0.16em;
     text-transform: uppercase;
     color: var(--accent);
     display: inline-flex;
     align-items: center;
     gap: 0.6rem;
     margin-bottom: 1rem;
   }
   
   .section-tag::before {
     content: '';
     display: block;
     width: 20px;
     height: 1px;
     background: var(--accent);
   }
   
   .section-title {
     font-family: var(--font-display);
     font-weight: 700;
     font-size: clamp(1.8rem, 4vw, 3rem);
     letter-spacing: -0.02em;
     color: var(--white);
     margin-bottom: 1.2rem;
     line-height: 1.1;
   }
   
   .section-intro {
     font-size: 1.05rem;
     color: var(--text-muted);
     max-width: 580px;
     line-height: 1.8;
   }
   
   .divider {
     height: 1px;
     background: linear-gradient(to right, transparent, var(--border-bright), transparent);
     margin: 0;
   }
   
   /* ============================================================
      CARDS
      ============================================================ */
   .card {
     background: var(--surface);
     border: 1px solid var(--border);
     border-radius: var(--radius-lg);
     padding: 2rem;
     transition: border-color var(--transition), box-shadow var(--transition);
   }
   
   .card:hover {
     border-color: var(--border-bright);
     box-shadow: 0 0 32px rgba(62, 201, 224, 0.05);
   }
   
   .card-icon {
     width: 40px;
     height: 40px;
     border-radius: var(--radius);
     background: var(--accent-dim);
     display: flex;
     align-items: center;
     justify-content: center;
     margin-bottom: 1.2rem;
     color: var(--accent);
     font-size: 1.2rem;
   }
   
   .card-title {
     font-family: var(--font-display);
     font-weight: 600;
     font-size: 1.05rem;
     color: var(--white);
     margin-bottom: 0.6rem;
     letter-spacing: -0.01em;
   }
   
   .card-body {
     font-size: 0.92rem;
     color: var(--text-muted);
     line-height: 1.7;
   }
   
   /* ============================================================
      STAT STRIP
      ============================================================ */
   .stats-strip {
     background: var(--bg-2);
     border-top: 1px solid var(--border);
     border-bottom: 1px solid var(--border);
     padding: 3rem 0;
   }
   
   .stats-grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
     gap: 2rem;
     text-align: center;
   }
   
   .stat-value {
     font-family: var(--font-display);
     font-size: 2.2rem;
     font-weight: 800;
     color: var(--accent);
     letter-spacing: -0.03em;
     line-height: 1;
     margin-bottom: 0.4rem;
   }
   
   .stat-label {
     font-family: var(--font-mono);
     font-size: 0.68rem;
     letter-spacing: 0.12em;
     text-transform: uppercase;
     color: var(--text-muted);
   }
   
   /* ============================================================
      GRID LAYOUTS
      ============================================================ */
   .grid-3 {
     display: grid;
     grid-template-columns: repeat(3, 1fr);
     gap: 1.5rem;
   }
   
   .grid-2 {
     display: grid;
     grid-template-columns: repeat(2, 1fr);
     gap: 1.5rem;
   }
   
   .grid-2-1 {
     display: grid;
     grid-template-columns: 2fr 1fr;
     gap: 3rem;
     align-items: start;
   }
   
   /* ============================================================
      PAGE HERO (inner pages)
      ============================================================ */
   .page-hero {
     padding: calc(var(--nav-h) + 5rem) 0 4rem;
     position: relative;
     overflow: hidden;
   }
   
   .page-hero-bg {
     position: absolute;
     inset: 0;
     background-image:
       linear-gradient(rgba(62, 201, 224, 0.025) 1px, transparent 1px),
       linear-gradient(90deg, rgba(62, 201, 224, 0.025) 1px, transparent 1px);
     background-size: 48px 48px;
     mask-image: radial-gradient(ellipse 100% 100% at 50% 0%, black 0%, transparent 70%);
   }
   
   .page-hero-content {
     position: relative;
   }
   
   .page-hero .section-title {
     font-size: clamp(2.2rem, 5vw, 4rem);
   }
   
   /* ============================================================
      SENSOR STACK CARDS
      ============================================================ */
   .stack-card {
     background: var(--surface);
     border: 1px solid var(--border);
     border-radius: var(--radius-lg);
     overflow: hidden;
     transition: border-color var(--transition), box-shadow var(--transition);
   }
   
   .stack-card:hover {
     border-color: var(--border-bright);
     box-shadow: 0 0 40px rgba(62, 201, 224, 0.06);
   }
   
   .stack-card-header {
     padding: 1.6rem 2rem;
     border-bottom: 1px solid var(--border);
     display: flex;
     align-items: center;
     gap: 1rem;
   }
   
   .stack-number {
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.1em;
     color: var(--accent);
     background: var(--accent-dim);
     padding: 0.2rem 0.5rem;
     border-radius: 2px;
     white-space: nowrap;
   }
   
   .stack-card-title {
     font-family: var(--font-display);
     font-weight: 700;
     font-size: 0.95rem;
     color: var(--white);
     letter-spacing: -0.01em;
   }
   
   .stack-card-body {
     padding: 1.6rem 2rem;
   }
   
   .stack-sensors {
     display: flex;
     flex-wrap: wrap;
     gap: 0.4rem;
     margin-bottom: 1.2rem;
   }
   
   .sensor-tag {
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.05em;
     padding: 0.2rem 0.55rem;
     border-radius: 2px;
     border: 1px solid var(--border-bright);
     color: var(--text-muted);
   }
   
   .stack-research-list {
     font-size: 0.88rem;
     color: var(--text-muted);
     line-height: 1.6;
   }
   
   .stack-research-list li {
     padding: 0.3rem 0;
     padding-left: 1rem;
     position: relative;
   }
   
   .stack-research-list li::before {
     content: '→';
     position: absolute;
     left: 0;
     color: var(--accent);
     font-size: 0.75rem;
   }
   
   /* ============================================================
      SENSOR TABLE
      ============================================================ */
   .sensor-table {
     width: 100%;
     border-collapse: collapse;
     font-size: 0.9rem;
   }
   
   .sensor-table th {
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.12em;
     text-transform: uppercase;
     color: var(--text-muted);
     text-align: left;
     padding: 0.8rem 1.2rem;
     border-bottom: 1px solid var(--border);
     font-weight: 400;
   }
   
   .sensor-table td {
     padding: 1rem 1.2rem;
     border-bottom: 1px solid var(--border);
     vertical-align: top;
     color: var(--text);
     font-size: 0.88rem;
     line-height: 1.5;
   }
   
   .sensor-table tr:last-child td {
     border-bottom: none;
   }
   
   .sensor-table tr:hover td {
     background: var(--accent-glow);
   }
   
   .sensor-table td:first-child {
     font-family: var(--font-mono);
     font-size: 0.8rem;
     color: var(--accent);
     white-space: nowrap;
   }
   
   /* ============================================================
      COMING SOON BLOCK
      ============================================================ */
   .coming-soon {
     text-align: center;
     padding: 6rem 2rem;
     border: 1px dashed var(--border-bright);
     border-radius: var(--radius-lg);
     background: var(--accent-glow);
   }
   
   .coming-soon-icon {
     font-size: 2.5rem;
     margin-bottom: 1.5rem;
     opacity: 0.5;
   }
   
   .coming-soon h3 {
     font-family: var(--font-display);
     font-weight: 700;
     font-size: 1.3rem;
     color: var(--white);
     margin-bottom: 0.6rem;
   }
   
   .coming-soon p {
     font-size: 0.95rem;
     color: var(--text-muted);
     max-width: 400px;
     margin: 0 auto 2rem;
   }
   
   /* ============================================================
      TIMELINE
      ============================================================ */
   .timeline {
     position: relative;
     padding-left: 2rem;
   }
   
   .timeline::before {
     content: '';
     position: absolute;
     left: 0;
     top: 8px;
     bottom: 8px;
     width: 1px;
     background: linear-gradient(to bottom, var(--accent), var(--border));
   }
   
   .timeline-item {
     position: relative;
     padding-bottom: 2.5rem;
   }
   
   .timeline-item:last-child {
     padding-bottom: 0;
   }
   
   .timeline-dot {
     position: absolute;
     left: -2rem;
     top: 8px;
     transform: translateX(-50%);
     width: 8px;
     height: 8px;
     border-radius: 50%;
     background: var(--accent);
     border: 1px solid var(--bg);
     box-shadow: 0 0 10px rgba(62, 201, 224, 0.5);
   }
   
   .timeline-dot.pending {
     background: var(--surface);
     border-color: var(--border-bright);
     box-shadow: none;
   }
   
   .timeline-label {
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.1em;
     text-transform: uppercase;
     color: var(--accent);
     margin-bottom: 0.3rem;
   }
   
   .timeline-title {
     font-family: var(--font-display);
     font-weight: 600;
     font-size: 0.95rem;
     color: var(--white);
     margin-bottom: 0.3rem;
   }
   
   .timeline-body {
     font-size: 0.88rem;
     color: var(--text-muted);
     line-height: 1.6;
   }
   
   /* ============================================================
      CONSTRAINT GRID
      ============================================================ */
   .constraint-item {
     padding: 1.4rem;
     border: 1px solid var(--border);
     border-radius: var(--radius);
     background: var(--surface);
     transition: border-color var(--transition);
   }
   
   .constraint-item:hover {
     border-color: var(--border-bright);
   }
   
   .constraint-label {
     font-family: var(--font-mono);
     font-size: 0.68rem;
     letter-spacing: 0.1em;
     text-transform: uppercase;
     color: var(--amber);
     margin-bottom: 0.5rem;
   }
   
   .constraint-text {
     font-size: 0.88rem;
     color: var(--text-muted);
     line-height: 1.6;
   }
   
   /* ============================================================
      CONTACT FORM
      ============================================================ */
   .form-group {
     margin-bottom: 1.4rem;
   }
   
   .form-label {
     display: block;
     font-family: var(--font-mono);
     font-size: 0.68rem;
     letter-spacing: 0.1em;
     text-transform: uppercase;
     color: var(--text-muted);
     margin-bottom: 0.5rem;
   }
   
   .form-input,
   .form-textarea,
   .form-select {
     width: 100%;
     background: var(--surface);
     border: 1px solid var(--border);
     border-radius: var(--radius);
     padding: 0.8rem 1rem;
     color: var(--text);
     font-family: var(--font-body);
     font-size: 0.95rem;
     transition: border-color var(--transition), box-shadow var(--transition);
     outline: none;
   }
   
   .form-input:focus,
   .form-textarea:focus,
   .form-select:focus {
     border-color: var(--accent);
     box-shadow: 0 0 0 3px rgba(62, 201, 224, 0.08);
   }
   
   .form-textarea {
     resize: vertical;
     min-height: 140px;
   }
   
   .form-select option {
     background: var(--surface);
     color: var(--text);
   }
   
   /* ============================================================
      FOOTER
      ============================================================ */
   .footer {
     background: var(--bg-2);
     border-top: 1px solid var(--border);
     padding: 4rem 0 2rem;
   }
   
   .footer-top {
     display: grid;
     grid-template-columns: 1.6fr 1fr 1fr;
     gap: 4rem;
     margin-bottom: 3rem;
   }
   
   .footer-brand-name {
     font-family: var(--font-display);
     font-weight: 800;
     font-size: 1.1rem;
     letter-spacing: 0.12em;
     color: var(--accent);
     margin-bottom: 0.3rem;
   }
   
   .footer-brand-full {
     font-family: var(--font-mono);
     font-size: 0.62rem;
     letter-spacing: 0.05em;
     color: var(--text-faint);
     margin-bottom: 1rem;
   }
   
   .footer-tagline {
     font-size: 0.88rem;
     color: var(--text-muted);
     line-height: 1.7;
     max-width: 280px;
   }
   
   .footer-col-title {
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.14em;
     text-transform: uppercase;
     color: var(--text-muted);
     margin-bottom: 1rem;
   }
   
   .footer-links {
     display: flex;
     flex-direction: column;
     gap: 0.6rem;
   }
   
   .footer-links a {
     font-size: 0.88rem;
     color: var(--text-faint);
     transition: color var(--transition);
   }
   
   .footer-links a:hover {
     color: var(--accent);
   }
   
   .footer-bottom {
     padding-top: 2rem;
     border-top: 1px solid var(--border);
     display: flex;
     align-items: center;
     justify-content: space-between;
     gap: 1rem;
   }
   
   .footer-copy {
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.06em;
     color: var(--text-faint);
   }
   
   .footer-status {
     display: flex;
     align-items: center;
     gap: 0.5rem;
     font-family: var(--font-mono);
     font-size: 0.65rem;
     letter-spacing: 0.06em;
     color: var(--text-faint);
   }
   
   .status-dot {
     width: 6px;
     height: 6px;
     border-radius: 50%;
     background: var(--amber);
     animation: pulse 2.5s ease infinite;
   }
   
   /* ============================================================
      INLINE HIGHLIGHT / MONO SPANS
      ============================================================ */
   .mono {
     font-family: var(--font-mono);
     font-size: 0.85em;
     color: var(--accent);
   }
   
   .highlight {
     color: var(--accent);
   }
   
   .text-muted {
     color: var(--text-muted);
   }
   
   .text-amber {
     color: var(--amber);
   }
   
   /* ============================================================
      NOTICE BANNER
      ============================================================ */
   .notice {
     background: var(--amber-dim);
     border: 1px solid rgba(224, 165, 62, 0.25);
     border-radius: var(--radius);
     padding: 1rem 1.4rem;
     font-size: 0.88rem;
     color: var(--amber);
     display: flex;
     align-items: flex-start;
     gap: 0.8rem;
     margin-bottom: 2rem;
   }
   
   .notice-icon {
     flex-shrink: 0;
     margin-top: 1px;
   }
   
   /* ============================================================
      ANIMATIONS
      ============================================================ */
   @keyframes fadeUp {
     from { opacity: 0; transform: translateY(22px); }
     to   { opacity: 1; transform: translateY(0); }
   }
   
   @keyframes fadeIn {
     from { opacity: 0; }
     to   { opacity: 1; }
   }
   
   @keyframes scrollPulse {
     0%, 100% { opacity: 0.4; }
     50%       { opacity: 1; }
   }
   
   @keyframes pulse {
     0%, 100% { opacity: 0.5; transform: scale(1); }
     50%       { opacity: 1; transform: scale(1.3); }
   }
   
   .fade-in {
     opacity: 0;
     transform: translateY(18px);
     transition: opacity 0.6s ease, transform 0.6s ease;
   }
   
   .fade-in.visible {
     opacity: 1;
     transform: translateY(0);
   }
   
   /* ============================================================
      RESPONSIVE
      ============================================================ */
   @media (max-width: 1024px) {
     .grid-3 { grid-template-columns: repeat(2, 1fr); }
     .footer-top { grid-template-columns: 1fr 1fr; gap: 2.5rem; }
     .grid-2-1 { grid-template-columns: 1fr; gap: 2rem; }
   }
   
   @media (max-width: 768px) {
     :root { --nav-h: 60px; }
   
     .nav { padding: 0 1.25rem; }
   
     /* Mobile nav menu — slide down with opacity transition */
     .nav-links {
       display: flex;
       flex-direction: column;
       position: fixed;
       top: var(--nav-h);
       left: 0;
       right: 0;
       background: rgba(8, 12, 18, 0.97);
       padding: 1.5rem 1.25rem 2rem;
       gap: 0;
       border-bottom: 1px solid var(--border);
       /* Hidden state */
       opacity: 0;
       pointer-events: none;
       transform: translateY(-8px);
       transition: opacity var(--transition), transform var(--transition);
     }
   
     .nav-links.open {
       opacity: 1;
       pointer-events: auto;
       transform: translateY(0);
     }
   
     .nav-links a {
       padding: 0.85rem 0;
       border-bottom: 1px solid var(--border);
       font-size: 0.82rem;
     }
   
     .nav-links a:last-child {
       border-bottom: none;
     }
   
     /* Remove the underline pseudo-element on mobile nav items */
     .nav-links a::after { display: none; }
   
     .nav-toggle { display: flex; }
   
     .container { padding: 0 1.25rem; }
     .section { padding: 4.5rem 0; }
     .section-sm { padding: 3rem 0; }
   
     .hero { padding: calc(var(--nav-h) + 2.5rem) 1.25rem 3rem; }
     .hero-scroll { display: none; } /* hide scroll indicator on mobile */
   
     .page-hero { padding: calc(var(--nav-h) + 3rem) 0 3rem; }
   
     .grid-3, .grid-2 { grid-template-columns: 1fr; }
   
     .stats-strip { padding: 2rem 0; }
     .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
   
     .footer-top { grid-template-columns: 1fr; gap: 2rem; }
     .footer-bottom { flex-direction: column; text-align: center; }
   
     /* Make tables scroll horizontally on mobile */
     .sensor-table-wrap {
       overflow-x: auto;
       -webkit-overflow-scrolling: touch;
       border: 1px solid var(--border);
       border-radius: var(--radius);
     }
   
     .coming-soon { padding: 3.5rem 1.5rem; }
   
     .stack-card-header { padding: 1.2rem 1.4rem; }
     .stack-card-body { padding: 1.2rem 1.4rem; }
   }
   
   @media (max-width: 480px) {
     .hero-title { font-size: 2.2rem; }
     .section-title { font-size: 1.8rem; }
     .page-hero .section-title { font-size: 2rem; }
     .stats-grid { grid-template-columns: repeat(2, 1fr); }
     .hero-cta { flex-direction: column; }
     .btn { justify-content: center; width: 100%; }
     .hero-cta .btn { width: auto; }
   
     .card { padding: 1.4rem; }
   
     .footer-top { gap: 1.5rem; }
   }