/* ==========================================================================
   Design System & Custom Properties (Light Mode: White & Warm Blue)
   ========================================================================== */
:root {
  --bg-primary: #f8fafc;     /* Soft off-white page background */
  --bg-secondary: #ffffff;   /* Pure white card backgrounds */
  --bg-card: #ffffff;
  --bg-card-hover: #ffffff;
  
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;
  --border-focus: #3b82f6;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  
  --color-blue-light: #60a5fa;
  --color-blue-medium: #3b82f6;
  --color-blue-dark: #1d4ed8;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  
  --gradient-accent: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
  --gradient-hover: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
  --gradient-water: linear-gradient(180deg, #60a5fa 0%, #2563eb 100%);
  
  --font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: 0.15s ease;
  
  --shadow-premium: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
  --shadow-card: 0 1px 3px 0 rgba(0, 0, 0, 0.02), 0 1px 2px -1px rgba(0, 0, 0, 0.02);
  --shadow-glow: 0 4px 14px 0 rgba(59, 130, 246, 0.35);
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  scroll-behavior: smooth;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body {
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary);
}

/* Skip link for keyboard a11y */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--gradient-accent);
  color: #ffffff;
  padding: 1rem 2rem;
  z-index: 9999;
  font-weight: 600;
  border-radius: 0 0 8px 0;
  transition: top var(--transition-fast);
  text-decoration: none;
}

.skip-link:focus {
  top: 0;
  outline: none;
}

/* Focus styles for all elements */
*:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 4px;
}

/* Tabular numbers for clean alignments */
.tabular-nums {
  font-variant-numeric: tabular-nums;
}

/* Screen reader only utility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* Handle prefers-reduced-motion standard */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto !important;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================================================
   Typography & Layout Containers
   ========================================================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.25;
  text-wrap: balance;
  color: var(--text-primary);
}

p {
  color: var(--text-secondary);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
}

.brand-logo {
  font-size: 1.5rem;
}

.brand-name {
  font-size: 1.25rem;
  font-weight: 800;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.header-nav {
  display: flex;
  gap: 1.5rem;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-blue-medium);
}

/* ==========================================================================
   Hero Section (Clean & Airy)
   ========================================================================== */
.hero-section {
  position: relative;
  padding: 4.5rem 0 3rem;
  text-align: center;
  overflow: hidden;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.hero-bg-glow {
  position: absolute;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 450px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.05) 0%, rgba(255, 255, 255, 0) 70%);
  pointer-events: none;
}

.hero-title {
  font-size: clamp(2.25rem, 5vw, 3.25rem);
  font-weight: 800;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.15rem);
  max-width: 650px;
  margin: 0 auto;
  font-weight: 400;
  color: var(--text-secondary);
}

/* ==========================================================================
   Single Column Questionnaire Layout
   ========================================================================== */
.calculator-section {
  padding: 3.5rem 0;
  background-color: var(--bg-primary);
}

.single-column-container {
  max-width: 680px;
  margin: 0 auto;
  padding: 0 1rem;
}

.questions-column {
  width: 100%;
}

.form-title {
  font-size: 1.6rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.form-subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.question-card {
  position: relative;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.25rem;
  transition: border-color var(--transition-smooth), box-shadow var(--transition-smooth);
  box-shadow: var(--shadow-card);
}

.question-card:hover {
  border-color: var(--border-hover);
  box-shadow: 0 4px 10px -2px rgba(0, 0, 0, 0.03);
}

.question-num {
  position: absolute;
  top: 1.25rem;
  right: 1.5rem;
  font-size: 2rem;
  font-weight: 800;
  color: rgba(59, 130, 246, 0.1);
  line-height: 1;
}

.question-legend {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  padding-right: 2.5rem;
  color: var(--text-primary);
  border: none;
}

fieldset {
  border: none;
  padding: 0;
  margin: 0;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.margin-top-lg {
  margin-top: 1rem;
}

.field-label {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.form-select {
  appearance: none;
  background-color: var(--bg-primary);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%23475569'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2.5' d='M19 9l-7 7-7-7'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 1rem;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  color: var(--text-primary);
  padding: 0.75rem 2.5rem 0.75rem 1rem;
  font-size: 0.95rem;
  font-family: var(--font-sans);
  font-weight: 500;
  cursor: pointer;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.02);
}

.form-select:hover {
  border-color: #94a3b8;
}

.form-select:focus-visible {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.12);
  outline: none;
}

.form-select.has-error {
  border-color: var(--color-error) !important;
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.12) !important;
}

.error-msg {
  color: var(--color-error);
  font-size: 0.8rem;
  font-weight: 600;
  margin-top: 0.15rem;
  display: block;
}

.error-msg.hidden {
  display: none !important;
}

.calculate-btn-row {
  margin-top: 0.5rem;
}

.calculate-btn {
  width: 100%;
  padding: 1.1rem;
  border: none;
  border-radius: 10px;
  background: var(--gradient-accent);
  color: #ffffff;
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  box-shadow: var(--shadow-glow);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast);
}

.calculate-btn:hover {
  background: var(--gradient-hover);
  box-shadow: 0 6px 18px 0 rgba(59, 130, 246, 0.45);
  transform: translateY(-1px);
}

.calculate-btn:active {
  transform: translateY(0);
}

/* ==========================================================================
   Visualizer Card Panel (Now located below the button)
   ========================================================================== */
.visualizer-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: var(--shadow-card);
}

.visualizer-card h3 {
  font-size: 1.15rem;
  margin-bottom: 0.25rem;
  color: var(--color-blue-dark);
}

.visualizer-intro {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
}

.live-values-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.live-val-box {
  padding: 0.85rem;
  border-radius: 8px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  text-align: center;
}

.live-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  display: block;
}

.live-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-blue-medium);
  display: block;
  margin: 0.15rem 0;
}

.secondary-num {
  color: var(--text-primary);
}

.live-sublabel {
  font-size: 0.7rem;
  color: var(--text-muted);
  display: block;
}

/* Cylinder Water Tank Visualizer */
.cylinder-container-wrapper {
  display: flex;
  justify-content: center;
  margin: 1rem 0 1.5rem;
}

.tank-cylinder {
  position: relative;
  width: 120px;
  height: 240px;
  background: var(--bg-secondary);
  border: 4px solid #cbd5e1;
  border-radius: 20px;
  overflow: hidden;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.04) inset;
}

/* Grid lines inside cylinder */
.tank-grid-lines {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 1.25rem 0;
  pointer-events: none;
  z-index: 10;
}

.tank-grid-lines span {
  display: block;
  width: 100%;
  font-size: 0.6rem;
  font-weight: 700;
  color: var(--text-muted);
  border-bottom: 1px dashed rgba(71, 85, 105, 0.12);
  padding-left: 0.5rem;
  line-height: 1;
}

/* Water block and wave animations */
.tank-water {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 20%;
  background: var(--gradient-water);
  transition: height 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Wave SVGs positioning */
.water-waves {
  position: absolute;
  top: -18px;
  left: 0;
  width: 200%;
  height: 20px;
  overflow: hidden;
}

.wave-front {
  fill: #60a5fa;
  opacity: 0.8;
  animation: wave-slide 4s linear infinite;
}

.wave-back {
  fill: #3b82f6;
  opacity: 0.5;
  animation: wave-slide-reverse 6s linear infinite;
}

@keyframes wave-slide {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

@keyframes wave-slide-reverse {
  0% { transform: translateX(-50%); }
  100% { transform: translateX(0); }
}

/* Dynamic Status description */
.visualizer-status-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
}

.status-indicator-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--color-success);
  flex-shrink: 0;
  box-shadow: 0 0 6px var(--color-success);
  transition: background-color var(--transition-smooth), box-shadow var(--transition-smooth);
}

.status-text-desc {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
}

/* ==========================================================================
   Comprehensive Results Panel (revealed on submission)
   ========================================================================== */
.result-area-section {
  padding: 4.5rem 0;
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.result-display-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 3rem;
  box-shadow: var(--shadow-premium);
  animation: fadeIn 0.6s ease forwards;
}

.result-main-title {
  font-size: 1.8rem;
  color: var(--color-blue-dark);
  margin-bottom: 0.5rem;
  text-align: center;
}

.result-main-subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  text-align: center;
}

.result-details-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
  align-items: start;
}

.result-rec-info {
  display: flex;
  flex-direction: column;
}

.recommendation-header {
  font-size: 1.25rem;
  color: var(--color-blue-medium);
  margin-bottom: 0.75rem;
  border-bottom: 2px solid var(--bg-primary);
  padding-bottom: 0.5rem;
}

.recommendation-text {
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-secondary);
  margin-bottom: 1.75rem;
}

.features-checklist-box h4 {
  font-size: 1.05rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.features-list li {
  position: relative;
  padding-left: 1.5rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.features-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-blue-medium);
  font-weight: 900;
}

/* Math breakdown panel */
.result-math-breakdown {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  padding: 2rem;
  border-radius: 12px;
}

.result-math-breakdown h3 {
  font-size: 1.1rem;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.breakdown-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.breakdown-list li {
  display: flex;
  justify-content: space-between;
  font-size: 0.88rem;
  color: var(--text-secondary);
  border-bottom: 1px dashed var(--border-color);
  padding-bottom: 0.4rem;
}

.breakdown-list li:last-child {
  border-bottom: none;
  padding-bottom: 0;
  font-weight: 700;
  color: var(--color-blue-dark);
}

.breakdown-val {
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
  font-weight: 600;
}

.reset-button-row {
  display: flex;
  justify-content: center;
}

.reset-action-btn {
  padding: 0.75rem 1.75rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.reset-action-btn:hover {
  background: #f1f5f9;
  border-color: #cbd5e1;
}

/* ==========================================================================
   DOE vs AHAM Standard Section
   ========================================================================== */
.standards-section {
  padding: 5rem 0;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.section-title {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: var(--color-blue-dark);
}

.section-subtitle {
  text-align: center;
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 3.5rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.standards-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 3rem;
  align-items: center;
}

.standards-info-card h3 {
  font-size: 1.35rem;
  margin-bottom: 0.75rem;
}

.standards-info-card p {
  margin-bottom: 1rem;
  font-size: 0.95rem;
}

/* Note Alert */
.alert-box {
  display: flex;
  gap: 1rem;
  padding: 1.25rem;
  border-radius: 10px;
  margin-top: 1.5rem;
}

.note-alert {
  background: rgba(59, 130, 246, 0.04);
  border: 1px solid rgba(59, 130, 246, 0.12);
}

.alert-icon {
  font-size: 1.15rem;
  flex-shrink: 0;
}

.alert-content {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 0 !important;
}

/* Slider Box styling */
.interactive-slider-box {
  padding: 2rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
}

.interactive-slider-box h3 {
  font-size: 1.15rem;
  margin-bottom: 0.5rem;
}

.slider-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.75rem;
}

.slider-container {
  position: relative;
  margin-bottom: 2rem;
}

.capacity-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: #e2e8f0;
  outline: none;
  cursor: pointer;
}

.capacity-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--gradient-accent);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
  transition: transform var(--transition-fast);
}

.capacity-slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.capacity-slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border: none;
  border-radius: 50%;
  background: var(--gradient-accent);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
  transition: transform var(--transition-fast);
}

.capacity-slider::-moz-range-thumb:hover {
  transform: scale(1.2);
}

.slider-markers {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.slider-results-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
}

.slider-result-col {
  display: flex;
  flex-direction: column;
}

.slider-result-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
}

.slider-result-val {
  font-size: 1.5rem;
  font-weight: 800;
  margin: 0.15rem 0;
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
}

.highlight-val {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.slider-result-desc {
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Sizing Chart Section
   ========================================================================== */
.chart-section {
  padding: 5rem 0;
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
}

.table-wrapper {
  overflow-x: auto;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: var(--bg-secondary);
  box-shadow: var(--shadow-card);
}

.sizing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
  min-width: 700px;
}

.sizing-table th, .sizing-table td {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
}

.sizing-table thead tr {
  background: var(--bg-primary);
}

.sizing-table thead th {
  font-weight: 700;
  color: var(--color-blue-dark);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.sizing-table tbody th {
  font-weight: 700;
  color: var(--text-primary);
  max-width: 250px;
}

.condition-header {
  font-size: 0.9rem;
}

.condition-sub {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 400;
  margin-top: 0.2rem;
}

.sizing-table tbody td {
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

.sizing-table tbody tr:last-child th,
.sizing-table tbody tr:last-child td {
  border-bottom: none;
}

.sizing-table tbody tr:hover {
  background: var(--bg-primary);
}

/* ==========================================================================
   Buying Checklist & Sanity Check
   ========================================================================== */
.checklist-section {
  padding: 5rem 0;
  background-color: var(--bg-secondary);
}

.checklist-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  margin-bottom: 3.5rem;
}

.checklist-card {
  padding: 2.5rem 2rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  box-shadow: var(--shadow-card);
}

.card-icon {
  font-size: 2.25rem;
  margin-bottom: 0.75rem;
}

.checklist-card h3 {
  font-size: 1.25rem;
  margin-bottom: 1.25rem;
  color: var(--color-blue-dark);
}

.checklist-items {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.checklist-items li {
  position: relative;
  padding-left: 1.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.checklist-items li::before {
  content: "✔";
  position: absolute;
  left: 0;
  color: var(--color-blue-medium);
  font-weight: 900;
}

/* Sanity Check Box */
.sanity-check-box {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 2.5rem;
  box-shadow: var(--shadow-card);
}

.sanity-title-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.sanity-icon {
  font-size: 1.75rem;
  color: var(--color-warning);
}

.sanity-title-row h3 {
  font-size: 1.35rem;
  color: var(--color-blue-dark);
}

.sanity-content p {
  margin-bottom: 1.75rem;
  font-size: 1rem;
  color: var(--text-secondary);
}

.sanity-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.sanity-scenario {
  padding: 1.5rem;
  border-radius: 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
}

.sanity-scenario h4 {
  font-size: 1.05rem;
  margin-bottom: 0.5rem;
}

.undersized {
  border-left: 4px solid var(--color-error);
}

.oversized {
  border-left: 4px solid var(--color-warning);
}

.sanity-scenario p {
  font-size: 0.88rem;
  line-height: 1.5;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  margin-top: auto;
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0;
  text-align: center;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.footer-links a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--color-blue-medium);
  text-decoration: underline;
}

.site-footer p {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.footer-sub {
  font-size: 0.78rem !important;
  color: var(--text-muted);
}

.site-footer a {
  color: var(--color-blue-medium);
  text-decoration: none;
  font-weight: 600;
}

.site-footer a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Keyframes & Utilities
   ========================================================================== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ==========================================================================
   Media Queries & Responsive Styling
   ========================================================================== */
@media (max-width: 968px) {
  .result-details-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  
  .standards-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
  
  .checklist-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    gap: 1rem;
    align-items: center;
  }

  .header-nav {
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.75rem 1.25rem;
  }
  
  .result-display-card {
    padding: 2rem 1.25rem;
  }
  
  .sanity-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 1rem;
  }
  
  .calculator-card, .visualizer-card, .result-display-card {
    padding: 1.5rem 1rem;
  }
  
  .question-card {
    padding: 1.25rem 1rem;
  }
  
  .rec-pint-badge {
    padding: 1rem 1.5rem;
    gap: 0.75rem;
    border-radius: 1rem;
  }
  
  .rec-pint-number {
    font-size: 3.5rem;
  }
  
  .slider-results-row {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }
}

/* Giant Recommendation Callout Card */
.recommendation-callout-card {
  background: linear-gradient(135deg, #ffffff 0%, #f0f7ff 100%);
  border: 2px solid #bfdbfe;
  border-radius: 1.25rem;
  padding: 2.25rem 2rem;
  box-shadow: 0 10px 15px -3px rgba(59, 130, 246, 0.05), 0 4px 6px -2px rgba(59, 130, 246, 0.03);
  text-align: center;
  position: relative;
  overflow: hidden;
  margin-bottom: 1.5rem;
}

.recommendation-callout-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--gradient-accent);
}

.rec-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--color-blue-dark);
  letter-spacing: 0.1em;
  background: #dbeafe;
  padding: 0.35rem 0.85rem;
  border-radius: 9999px;
  text-transform: uppercase;
  margin-bottom: 1.25rem;
}

.rec-pint-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  background: var(--gradient-accent);
  padding: 1.25rem 2.25rem;
  border-radius: 1.25rem;
  margin: 0 auto 1.5rem auto;
  box-shadow: 0 10px 20px -5px rgba(29, 78, 216, 0.25);
  max-width: max-content;
  overflow: visible;
}

.rec-pint-number {
  font-size: 4.5rem;
  font-weight: 850;
  line-height: 1;
  color: #ffffff;
  letter-spacing: -0.02em;
  overflow: visible;
}

.rec-pint-unit {
  font-size: 1.25rem;
  font-weight: 700;
  color: #ffffff;
  line-height: 1.2;
  text-align: left;
}

.doe-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 800;
  background: rgba(255, 255, 255, 0.2);
  color: #ffffff;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  margin-top: 0.25rem;
  text-transform: uppercase;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.rec-class-title {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text-dark);
  margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
}

.rec-simple-desc {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.6;
  max-width: 500px;
  margin: 0 auto 1.5rem auto;
}

.rec-simple-desc strong {
  color: var(--text-dark);
  font-weight: 700;
}

.rec-equivalence-box {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 0.75rem;
  padding: 0.85rem 1.25rem;
  font-size: 0.9rem;
  color: var(--text-dark);
  line-height: 1.5;
  box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
}

.rec-equivalence-box strong {
  font-weight: 700;
}

/* Accordion details/summary styles */
.tech-details-accordion {
  border: 1px solid #e2e8f0;
  border-radius: 0.75rem;
  background: #ffffff;
  overflow: hidden;
  transition: all 0.3s ease;
}

.tech-details-accordion[open] {
  border-color: #bfdbfe;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.accordion-summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.15rem 1.5rem;
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-dark);
  background: #f8fafc;
  cursor: pointer;
  list-style: none; /* Hide default triangle */
  user-select: none;
  transition: background 0.2s ease;
}

.accordion-summary::-webkit-details-marker {
  display: none; /* Hide Safari default triangle */
}

.accordion-summary:hover {
  background: #f1f5f9;
}

.accordion-icon {
  font-size: 0.75rem;
  color: var(--text-muted);
  transition: transform 0.2s ease;
}

.tech-details-accordion[open] .accordion-icon {
  transform: rotate(180deg);
}

.accordion-content {
  padding: 1.5rem;
  border-top: 1px solid #e2e8f0;
  background: #ffffff;
}

.margin-top-md {
  margin-top: 1.5rem;
}

/* Buying Features Checklist Grid Layout */
.buying-features-checklist {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 0.75rem;
  padding: 1.5rem;
}

.features-intro-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  line-height: 1.5;
}

.features-category h5 {
  font-size: 0.95rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.cat-title.must-have {
  color: var(--color-blue-dark);
}

.cat-title.convenience {
  color: var(--text-primary);
}

.features-check-grid {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.features-check-grid li {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
  padding-left: 1.25rem;
  position: relative;
}

.features-check-grid li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--color-success);
  font-weight: 700;
}

@media (max-width: 600px) {
  .features-check-grid {
    grid-template-columns: 1fr;
  }
}

/* SEO Article Guide Section */
.seo-guide-section {
  padding: 4.5rem 0;
  background-color: #ffffff;
  border-top: 1px solid var(--border-color);
}

.seo-article {
  max-width: 800px;
  margin: 0 auto;
}

.seo-article-title {
  font-size: 2rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 2rem;
  text-align: center;
  letter-spacing: -0.02em;
}

.seo-article-content h3 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-blue-dark);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.seo-article-content p {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.seo-article-content ul, .seo-article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.seo-article-content li {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 0.75rem;
}

.seo-article-content strong {
  color: var(--text-primary);
}

@media (max-width: 768px) {
  .seo-guide-section {
    padding: 3rem 0;
  }
  .seo-article-title {
    font-size: 1.65rem;
  }
}

/* FAQ Accordion Styling */
.faq-section {
  padding: 4.5rem 0;
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border-color);
}

.faq-grid {
  max-width: 800px;
  margin: 2.5rem auto 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  overflow: hidden;
  transition: border-color var(--transition-smooth), box-shadow var(--transition-smooth);
}

.faq-item[open] {
  border-color: var(--border-focus);
  box-shadow: var(--shadow-premium);
}

.faq-question {
  padding: 1.25rem 1.5rem;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
}

.faq-question::-webkit-details-marker {
  display: none;
}

.faq-toggle {
  font-size: 0.8rem;
  color: var(--text-muted);
  transition: transform var(--transition-smooth);
}

.faq-item[open] .faq-toggle {
  transform: rotate(180deg);
  color: var(--color-blue-medium);
}

.faq-answer {
  padding: 0 1.5rem 1.5rem 1.5rem;
  border-top: 1px solid var(--bg-primary);
  margin-top: 0;
}

.faq-answer p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-top: 1rem;
}

@media (max-width: 768px) {
  .faq-section {
    padding: 3rem 0;
  }
}

/* MPA Secondary Pages Styling */
.page-hero-section {
  padding: 4rem 0 2.5rem;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  text-align: center;
}

.page-hero-section h1 {
  font-size: 2.5rem;
  font-weight: 850;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.page-hero-section p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.page-content-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2.5rem;
  margin: 3rem auto;
  max-width: 800px;
  box-shadow: var(--shadow-card);
}

.page-content-card h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-blue-dark);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.page-content-card p {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.page-content-card ul, .page-content-card ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.page-content-card li {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 0.75rem;
}

.page-content-card strong {
  color: var(--text-primary);
}

/* Contact Form Styling */
.contact-form {
  margin-top: 2rem;
}

.form-group-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

@media (max-width: 600px) {
  .form-group-row {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }
}

.contact-submit-btn {
  background: var(--gradient-accent);
  color: #ffffff;
  border: none;
  border-radius: 8px;
  padding: 0.85rem 2rem;
  font-size: 1rem;
  font-family: var(--font-sans);
  font-weight: 700;
  cursor: pointer;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  box-shadow: var(--shadow-glow);
  width: 100%;
}

.contact-submit-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px 0 rgba(59, 130, 246, 0.4);
}

.contact-submit-btn:active {
  transform: translateY(0);
}

/* Error Page Specific Layout */
.error-page-card {
  text-align: center;
  max-width: 500px;
  margin: 5rem auto;
  padding: 3.5rem 2rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  box-shadow: var(--shadow-premium);
}

.error-code {
  font-size: 6rem;
  font-weight: 900;
  line-height: 1;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 1rem;
}

.error-title {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.error-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 2rem;
}

.error-home-btn {
  display: inline-block;
  background: var(--gradient-accent);
  color: #ffffff;
  text-decoration: none;
  font-weight: 700;
  padding: 0.85rem 2rem;
  border-radius: 8px;
  box-shadow: var(--shadow-glow);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.error-home-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px 0 rgba(59, 130, 246, 0.4);
}

.hidden {
  display: none !important;
}