/* ============================================================
   POROSIMETRY.COM — Global Stylesheet
   Design System: Precision Scientific Editorial
   ============================================================ */

/* --- CSS Custom Properties --- */
:root {
  /* Primary Palette — Deep scientific blues */
  --color-bg:          #0B1120;
  --color-bg-elevated: #111827;
  --color-bg-card:     #151E2E;
  --color-bg-subtle:   #1A2332;
  --color-surface:     #1E293B;

  /* Accent — Lab-instrument cyan/teal */
  --color-accent:      #22D3EE;
  --color-accent-dim:  #0891B2;
  --color-accent-glow: rgba(34, 211, 238, 0.15);
  --color-accent-soft: rgba(34, 211, 238, 0.08);

  /* Secondary accent — Warm amber for CTA */
  --color-cta:         #F59E0B;
  --color-cta-hover:   #FBBF24;

  /* Text hierarchy */
  --color-text:        #E2E8F0;
  --color-text-muted:  #94A3B8;
  --color-text-dim:    #64748B;
  --color-heading:     #F1F5F9;

  /* Borders */
  --color-border:      rgba(148, 163, 184, 0.12);
  --color-border-hover:rgba(34, 211, 238, 0.3);

  /* Typography */
  --font-display:      'DM Serif Display', Georgia, serif;
  --font-heading:      'Instrument Sans', 'Segoe UI', sans-serif;
  --font-body:         'Source Sans 3', 'Segoe UI', sans-serif;
  --font-mono:         'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing scale */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Layout */
  --max-width:     1280px;
  --max-width-sm:  960px;
  --radius:        6px;
  --radius-lg:     12px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --duration: 0.3s;
}


/* --- Reset & Base --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }
a { color: var(--color-accent); text-decoration: none; transition: color var(--duration) var(--ease-out); }
a:hover { color: var(--color-accent-dim); }
button { cursor: pointer; font-family: inherit; }

/* Focus styles */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}


/* --- Utility --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.container--sm {
  max-width: var(--max-width-sm);
}

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

.section {
  padding-block: var(--space-4xl);
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.section-label::before {
  content: '';
  display: inline-block;
  width: 24px;
  height: 1px;
  background: var(--color-accent);
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  color: var(--color-heading);
  line-height: 1.2;
  margin-bottom: var(--space-md);
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 640px;
  line-height: 1.7;
}


/* --- Header / Navigation --- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(11, 17, 32, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--duration) var(--ease-out),
              box-shadow var(--duration) var(--ease-out);
}

.site-header.scrolled {
  background: rgba(11, 17, 32, 0.95);
  box-shadow: 0 4px 30px rgba(0,0,0,0.3);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--color-heading);
  text-decoration: none;
}

.logo-icon {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-dim));
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.logo-icon::after {
  content: '';
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 2px solid var(--color-bg);
  background: transparent;
}

.logo span {
  color: var(--color-accent);
}

/* Main nav */
.main-nav { display: flex; align-items: center; gap: var(--space-xs); }

.nav-link {
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius);
  transition: color var(--duration) var(--ease-out),
              background var(--duration) var(--ease-out);
  white-space: nowrap;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--color-heading);
  background: var(--color-accent-soft);
}

.nav-link--active {
  color: var(--color-accent);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.nav-dropdown-trigger {
  display: flex;
  align-items: center;
  gap: 4px;
  background: none;
  border: none;
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius);
  transition: color var(--duration) var(--ease-out),
              background var(--duration) var(--ease-out);
}

.nav-dropdown-trigger:hover {
  color: var(--color-heading);
  background: var(--color-accent-soft);
}

.nav-dropdown-trigger svg {
  width: 14px;
  height: 14px;
  transition: transform var(--duration) var(--ease-out);
}

.nav-dropdown.open .nav-dropdown-trigger svg {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(-4px);
  min-width: 260px;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-sm);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity var(--duration) var(--ease-out),
              transform var(--duration) var(--ease-out),
              visibility var(--duration);
  box-shadow: 0 20px 50px rgba(0,0,0,0.4);
}

.nav-dropdown.open .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: all;
  transform: translateX(-50%) translateY(0);
}

.dropdown-link {
  display: block;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius);
  color: var(--color-text-muted);
  font-size: 0.875rem;
  transition: background var(--duration) var(--ease-out),
              color var(--duration) var(--ease-out);
}

.dropdown-link:hover {
  background: var(--color-accent-soft);
  color: var(--color-heading);
}

.dropdown-link small {
  display: block;
  font-size: 0.75rem;
  color: var(--color-text-dim);
  margin-top: 2px;
}

.nav-cta {
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-bg);
  background: var(--color-accent);
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius);
  border: none;
  transition: background var(--duration) var(--ease-out),
              transform var(--duration) var(--ease-out);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: var(--space-sm);
}

.nav-cta:hover {
  background: var(--color-cta);
  color: var(--color-bg);
  transform: translateY(-1px);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text);
  padding: var(--space-sm);
}

.nav-toggle svg {
  width: 24px;
  height: 24px;
}


/* --- Hero Section --- */
.hero {
  padding-top: calc(72px + var(--space-4xl));
  padding-bottom: var(--space-4xl);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px;
  right: -200px;
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--color-accent-glow) 0%, transparent 70%);
  pointer-events: none;
  animation: heroGlow 8s ease-in-out infinite alternate;
}

@keyframes heroGlow {
  0%   { opacity: 0.4; transform: translate(0, 0); }
  100% { opacity: 0.7; transform: translate(-40px, 40px); }
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.hero-label .pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; box-shadow: 0 0 0 0 rgba(34, 211, 238, 0.6); }
  50%      { opacity: 0.8; box-shadow: 0 0 0 8px rgba(34, 211, 238, 0); }
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  color: var(--color-heading);
  line-height: 1.1;
  margin-bottom: var(--space-lg);
}

.hero-title em {
  font-style: normal;
  color: var(--color-accent);
  position: relative;
}

.hero-description {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  line-height: 1.75;
  margin-bottom: var(--space-2xl);
  max-width: 540px;
}

.hero-actions {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.85rem 1.75rem;
  border-radius: var(--radius);
  border: none;
  transition: all var(--duration) var(--ease-out);
  text-decoration: none;
}

.btn--primary {
  background: var(--color-accent);
  color: var(--color-bg);
}

.btn--primary:hover {
  background: var(--color-cta);
  color: var(--color-bg);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(34, 211, 238, 0.25);
}

.btn--outline {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn--outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-soft);
}

.btn svg { width: 18px; height: 18px; }

/* Hero visual — pore network diagram */
.hero-visual {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-diagram {
  width: 100%;
  max-width: 480px;
  aspect-ratio: 1;
  position: relative;
}

.hero-diagram canvas {
  width: 100%;
  height: 100%;
  border-radius: var(--radius-lg);
}

/* Trust bar */
.hero-trust {
  margin-top: var(--space-3xl);
  padding-top: var(--space-2xl);
  border-top: 1px solid var(--color-border);
}

.trust-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-text-dim);
  margin-bottom: var(--space-lg);
}

.trust-items {
  display: flex;
  gap: var(--space-2xl);
  flex-wrap: wrap;
  align-items: center;
}

.trust-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.trust-item svg {
  width: 18px;
  height: 18px;
  color: var(--color-accent);
  flex-shrink: 0;
}


/* --- Metrics Bar --- */
.metrics {
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding-block: var(--space-2xl);
  background: var(--color-bg-elevated);
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
  text-align: center;
}

.metric-value {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  color: var(--color-accent);
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.metric-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-dim);
}


/* --- Core Methods Section --- */
.methods {
  background: var(--color-bg);
}

.methods-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.methods-header .section-subtitle {
  margin-inline: auto;
}

.methods-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.method-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  transition: border-color var(--duration) var(--ease-out),
              transform var(--duration) var(--ease-out),
              box-shadow var(--duration) var(--ease-out);
  position: relative;
  overflow: hidden;
}

.method-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.5s var(--ease-out);
}

.method-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.3);
}

.method-card:hover::before {
  transform: scaleX(1);
}

.method-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius);
  background: var(--color-accent-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-lg);
}

.method-icon svg {
  width: 26px;
  height: 26px;
  color: var(--color-accent);
}

.method-tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent-dim);
  margin-bottom: var(--space-sm);
}

.method-card h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-heading);
  margin-bottom: var(--space-sm);
}

.method-card p {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  line-height: 1.7;
}

.method-specs {
  list-style: none;
  margin-bottom: var(--space-lg);
}

.method-specs li {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
}

.method-specs li:last-child { border-bottom: none; }

.method-specs .spec-label { color: var(--color-text-dim); }
.method-specs .spec-value {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--color-accent);
}

.method-link {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.875rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-accent);
  transition: gap var(--duration) var(--ease-out);
}

.method-link:hover { gap: 10px; }

.method-link svg { width: 16px; height: 16px; }


/* --- Comparison Section --- */
.comparison {
  background: var(--color-bg-elevated);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

.comparison-content { max-width: 500px; }

.comparison-list {
  list-style: none;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.comparison-list li {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
}

.comparison-list li:last-child { border-bottom: none; }

.comparison-list .check {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-accent-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 2px;
}

.comparison-list .check svg {
  width: 12px; height: 12px;
  color: var(--color-accent);
}

.comparison-list .text strong {
  display: block;
  color: var(--color-heading);
  font-size: 0.92rem;
  margin-bottom: 2px;
}

.comparison-list .text span {
  font-size: 0.82rem;
  color: var(--color-text-dim);
}

/* Comparison table card */
.comparison-table-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.comparison-table-header {
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--color-heading);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}

.comparison-table th,
.comparison-table td {
  padding: var(--space-sm) var(--space-lg);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.comparison-table th {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-dim);
  background: var(--color-bg-subtle);
}

.comparison-table td {
  color: var(--color-text-muted);
}

.comparison-table td:first-child {
  color: var(--color-heading);
  font-weight: 500;
}

.comparison-table tr:last-child td { border-bottom: none; }

.comparison-table .highlight {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 0.78rem;
}


/* --- Applications / Industries --- */
.applications-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
  margin-top: var(--space-3xl);
}

.app-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: border-color var(--duration) var(--ease-out),
              transform var(--duration) var(--ease-out);
}

.app-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-2px);
}

.app-card-icon {
  font-size: 1.5rem;
  margin-bottom: var(--space-md);
}

.app-card h3 {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-heading);
  margin-bottom: var(--space-sm);
}

.app-card p {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}


/* --- Pore Calculator Tool --- */
.calculator {
  background: var(--color-bg-elevated);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.calculator-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

.calc-box {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
}

.calc-box h3 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-heading);
  margin-bottom: var(--space-xs);
}

.calc-box .calc-desc {
  font-size: 0.85rem;
  color: var(--color-text-dim);
  margin-bottom: var(--space-xl);
}

.calc-field {
  margin-bottom: var(--space-lg);
}

.calc-field label {
  display: block;
  font-family: var(--font-heading);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.calc-field input,
.calc-field select {
  width: 100%;
  padding: 0.65rem 0.9rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  transition: border-color var(--duration) var(--ease-out);
  appearance: none;
}

.calc-field input:focus,
.calc-field select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.calc-field select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%2394A3B8'%3E%3Cpath d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

.calc-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.calc-btn {
  width: 100%;
  padding: 0.75rem;
  background: var(--color-accent);
  color: var(--color-bg);
  border: none;
  border-radius: var(--radius);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.9rem;
  transition: background var(--duration) var(--ease-out);
  margin-top: var(--space-sm);
}

.calc-btn:hover { background: var(--color-cta); }

.calc-result {
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  background: var(--color-accent-soft);
  border: 1px solid var(--color-border-hover);
  border-radius: var(--radius);
  display: none;
}

.calc-result.visible { display: block; }

.calc-result-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent-dim);
  margin-bottom: var(--space-xs);
}

.calc-result-value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-accent);
}

.calc-result-equation {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--color-text-dim);
  margin-top: var(--space-sm);
}


/* --- Standards & Authority --- */
.standards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

.standard-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.standard-card h4 {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
}

.standard-card p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}


/* --- Lead Generation / CTA Section --- */
.cta-section {
  background: linear-gradient(135deg, var(--color-bg-elevated) 0%, var(--color-bg-subtle) 100%);
  border-top: 1px solid var(--color-border);
}

.cta-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
}

.cta-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  transition: border-color var(--duration) var(--ease-out);
}

.cta-card:hover {
  border-color: var(--color-border-hover);
}

.cta-card h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-heading);
  margin-bottom: var(--space-sm);
}

.cta-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
}

.cta-card .btn { width: 100%; justify-content: center; }

/* Whitepaper list */
.whitepaper-list {
  list-style: none;
  margin-bottom: var(--space-xl);
}

.whitepaper-list li {
  padding: var(--space-sm) 0;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.whitepaper-list li svg {
  width: 16px; height: 16px;
  color: var(--color-accent);
  flex-shrink: 0;
}

/* RFQ form */
.rfq-form { display: flex; flex-direction: column; gap: var(--space-md); }

.rfq-form input,
.rfq-form select,
.rfq-form textarea {
  width: 100%;
  padding: 0.7rem 0.9rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 0.88rem;
  transition: border-color var(--duration) var(--ease-out);
}

.rfq-form input:focus,
.rfq-form select:focus,
.rfq-form textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.rfq-form select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%2394A3B8'%3E%3Cpath d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

.rfq-form textarea {
  min-height: 80px;
  resize: vertical;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}


/* --- Footer --- */
.site-footer {
  background: var(--color-bg-elevated);
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-3xl);
}

.footer-brand p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-top: var(--space-md);
  max-width: 320px;
}

.footer-col h4 {
  font-family: var(--font-heading);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-dim);
  margin-bottom: var(--space-lg);
}

.footer-links {
  list-style: none;
}

.footer-links li { margin-bottom: var(--space-sm); }

.footer-links a {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  transition: color var(--duration) var(--ease-out);
}

.footer-links a:hover { color: var(--color-accent); }

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-xl);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-bottom p {
  font-size: 0.78rem;
  color: var(--color-text-dim);
}

.footer-bottom-links {
  display: flex;
  gap: var(--space-lg);
}

.footer-bottom-links a {
  font-size: 0.78rem;
  color: var(--color-text-dim);
}

.footer-bottom-links a:hover { color: var(--color-accent); }


/* --- Scroll Reveal Animations --- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s var(--ease-out),
              transform 0.7s var(--ease-out);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }


/* --- Responsive --- */
@media (max-width: 1024px) {
  .hero-grid { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
  .methods-grid { grid-template-columns: 1fr 1fr; }
  .applications-grid { grid-template-columns: 1fr 1fr; }
  .comparison-grid { grid-template-columns: 1fr; }
  .calculator-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  :root {
    --space-4xl: 3rem;
    --space-3xl: 2rem;
  }

  .nav-toggle { display: flex; }

  .main-nav {
    position: fixed;
    top: 72px; left: 0; right: 0; bottom: 0;
    background: var(--color-bg-elevated);
    flex-direction: column;
    padding: var(--space-xl);
    gap: var(--space-xs);
    transform: translateX(100%);
    transition: transform 0.4s var(--ease-out);
    overflow-y: auto;
  }

  .main-nav.open {
    transform: translateX(0);
  }

  .nav-dropdown-menu {
    position: static;
    transform: none;
    box-shadow: none;
    border: none;
    background: var(--color-bg-subtle);
    border-radius: var(--radius);
    margin-top: var(--space-xs);
  }

  .nav-dropdown.open .nav-dropdown-menu {
    transform: none;
  }

  .nav-cta {
    margin-left: 0;
    margin-top: var(--space-md);
    justify-content: center;
  }

  .methods-grid { grid-template-columns: 1fr; }
  .metrics-grid { grid-template-columns: 1fr 1fr; gap: var(--space-lg); }
  .applications-grid { grid-template-columns: 1fr; }
  .cta-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .calc-row { grid-template-columns: 1fr; }
  .standards-grid { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { justify-content: center; }
}