/* ==========================================================================
   BMI CALCULATOR - PRODUCTION CORE STYLESHEET
   High-Performance, Zero-CLS, Mobile-First, Light/Dark Theming
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Custom Properties (Theme Tokens)
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette - Light Theme (Default) */
  --bg-body: #f8fafc;
  --bg-surface: #ffffff;
  --bg-card: #ffffff;
  --bg-card-subtle: #f1f5f9;
  --bg-input: #ffffff;
  --bg-hover: #f1f5f9;
  
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --text-inverse: #ffffff;
  
  --border-subtle: #e2e8f0;
  --border-medium: #cbd5e1;
  --border-focus: #2563eb;
  
  --brand-primary: #2563eb;
  --brand-primary-hover: #1d4ed8;
  --brand-primary-light: #dbeafe;
  --brand-accent: #0284c7;
  
  /* Medical Category Status Colors (WCAG AA Compliant) */
  --color-severe-thin: #3b82f6; /* Severe Thinness (< 16.0) */
  --color-underweight: #0284c7;  /* Underweight (16.0 - 18.4) */
  --color-normal: #16a34a;       /* Normal Weight (18.5 - 24.9) */
  --color-overweight: #d97706;   /* Overweight (25.0 - 29.9) */
  --color-obese1: #ea580c;       /* Obese Class I (30.0 - 34.9) */
  --color-obese2: #dc2626;       /* Obese Class II (35.0 - 39.9) */
  --color-obese3: #991b1b;       /* Obese Class III (≥ 40.0) */
  
  /* Shadows & Elevations */
  --shadow-sm: 0 1px 2px 0 rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.07), 0 2px 4px -2px rgba(15, 23, 42, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.04);
  --shadow-xl: 0 20px 25px -5px rgba(15, 23, 42, 0.1), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
  
  /* Radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-body: #090d16;
  --bg-surface: #0f172a;
  --bg-card: #131d31;
  --bg-card-subtle: #1e293b;
  --bg-input: #0f172a;
  --bg-hover: #1e293b;
  
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #0f172a;
  
  --border-subtle: #1e293b;
  --border-medium: #334155;
  --border-focus: #3b82f6;
  
  --brand-primary: #3b82f6;
  --brand-primary-hover: #60a5fa;
  --brand-primary-light: #1e3a8a;
  --brand-accent: #38bdf8;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
}

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

html {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-body);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-body);
  color: var(--text-primary);
  transition: background-color var(--transition-base), color var(--transition-base);
}

img, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--brand-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  text-decoration: underline;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

/* --------------------------------------------------------------------------
   Layout Containers & Grid System
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding-left: clamp(16px, 4vw, 24px);
  padding-right: clamp(16px, 4vw, 24px);
}

.container-narrow {
  max-width: 860px;
}

.main-content {
  flex: 1 0 auto;
  padding-bottom: 64px;
}

/* --------------------------------------------------------------------------
   Breadcrumbs (Semantic & Visible)
   -------------------------------------------------------------------------- */
.breadcrumbs {
  padding: 16px 0 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.breadcrumb-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb-item a {
  color: var(--text-secondary);
  font-weight: 500;
}

.breadcrumb-item a:hover {
  color: var(--brand-primary);
}

.breadcrumb-item[aria-current="page"] {
  color: var(--text-primary);
  font-weight: 600;
}

.breadcrumb-separator {
  color: var(--text-muted);
  user-select: none;
}

/* --------------------------------------------------------------------------
   Header & Top-Right Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  transition: background-color var(--transition-base), border-color var(--transition-base);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 20px;
}

.site-logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.site-logo:hover {
  text-decoration: none;
  color: var(--brand-primary);
}

.logo-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #2563eb, #0284c7);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-weight: 800;
  font-size: 1.15rem;
  box-shadow: var(--shadow-sm);
}

/* Top-Right Menu & Navigation */
.header-right-nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

.site-nav {
  display: flex;
  align-items: center;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 14px;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.nav-link:hover {
  color: var(--brand-primary);
  background-color: var(--bg-hover);
  text-decoration: none;
}

.nav-link.active {
  color: var(--brand-primary);
  background-color: var(--brand-primary-light);
  font-weight: 600;
}

[data-theme="dark"] .nav-link.active {
  color: #93c5fd;
  background-color: rgba(37, 99, 235, 0.2);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.theme-toggle-btn {
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: all var(--transition-fast);
}

.theme-toggle-btn:hover {
  background-color: var(--bg-hover);
  border-color: var(--border-medium);
  transform: translateY(-1px);
}

.mobile-menu-btn {
  display: none;
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  width: 40px;
  height: 40px;
  padding: 0;
  color: var(--text-primary);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.mobile-menu-btn:hover {
  background-color: var(--bg-hover);
  border-color: var(--border-medium);
}

/* --------------------------------------------------------------------------
   Mobile Drawer & Backdrop Overlay
   -------------------------------------------------------------------------- */
.mobile-drawer-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 150;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
  backdrop-filter: blur(4px);
}

.mobile-drawer-backdrop.active {
  opacity: 1;
  visibility: visible;
}

.mobile-nav-drawer {
  position: fixed;
  top: 0;
  right: 0;
  width: min(340px, 85vw);
  height: 100vh;
  background-color: var(--bg-surface);
  box-shadow: var(--shadow-lg);
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
  border-left: 1px solid var(--border-subtle);
}

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

.mobile-drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 20px;
  border-bottom: 1px solid var(--border-subtle);
}

.mobile-drawer-close {
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.mobile-drawer-close:hover {
  background-color: var(--bg-hover);
  color: var(--color-obese-3);
}

.mobile-drawer-body {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.mobile-drawer-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.mobile-drawer-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-primary);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.mobile-drawer-link .link-icon {
  font-size: 1.2rem;
}

.mobile-drawer-link:hover {
  background-color: var(--bg-hover);
  color: var(--brand-primary);
  text-decoration: none;
}

.mobile-drawer-link.active {
  background-color: var(--brand-primary-light);
  color: var(--brand-primary);
  font-weight: 600;
}

[data-theme="dark"] .mobile-drawer-link.active {
  background-color: rgba(37, 99, 235, 0.25);
  color: #93c5fd;
}

.nav-badge {
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background-color: var(--brand-primary);
  color: #ffffff;
  font-weight: 700;
  margin-left: auto;
}

.mobile-drawer-footer {
  padding-top: 20px;
  border-top: 1px solid var(--border-subtle);
  margin-top: 24px;
}

.mobile-theme-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.theme-toggle-btn-mobile {
  padding: 8px 14px;
  border-radius: var(--radius-md);
  background: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
}

/* --------------------------------------------------------------------------
   Homepage Specific Styles
   -------------------------------------------------------------------------- */
.home-hero-section {
  padding: clamp(32px, 5vw, 64px) 0 clamp(24px, 4vw, 48px);
  background: linear-gradient(180deg, var(--bg-card-subtle) 0%, var(--bg-surface) 100%);
  border-bottom: 1px solid var(--border-subtle);
}

.home-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  align-items: center;
}

@media (min-width: 960px) {
  .home-hero-grid {
    grid-template-columns: 1.25fr 0.95fr;
    gap: 48px;
  }
}

.home-hero-title {
  font-size: clamp(2rem, 3.8vw, 2.75rem);
  font-weight: 800;
  line-height: 1.15;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  margin-bottom: 16px;
}

.home-hero-subtitle {
  font-size: clamp(1.05rem, 1.8vw, 1.2rem);
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 28px;
  max-width: 600px;
}

.home-hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-bottom: 28px;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1.05rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-arrow {
  transition: transform var(--transition-fast);
}

.btn-lg:hover .btn-arrow {
  transform: translateX(4px);
}

.trust-pills-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.trust-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.825rem;
  font-weight: 500;
  color: var(--text-secondary);
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  padding: 6px 12px;
  border-radius: var(--radius-full);
}

.trust-icon {
  font-size: 0.95rem;
}

/* Home Quick BMI Preview Widget */
.home-hero-widget-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  padding: 24px;
  position: relative;
  overflow: hidden;
}

.home-hero-widget-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #2563eb, #38bdf8, #10b981);
}

.widget-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.widget-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.widget-badge {
  font-size: 0.75rem;
  font-weight: 600;
  background-color: var(--brand-primary-light);
  color: var(--brand-primary);
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

[data-theme="dark"] .widget-badge {
  background-color: rgba(37, 99, 235, 0.25);
  color: #93c5fd;
}

.widget-body {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.widget-inputs-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.widget-result-box {
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.widget-bmi-val {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: baseline;
  gap: 6px;
  letter-spacing: -0.02em;
}

.widget-bmi-unit {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}

.widget-action-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border-radius: var(--radius-md);
  background-color: var(--brand-primary-light);
  color: var(--brand-primary);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.widget-action-link:hover {
  background-color: var(--brand-primary);
  color: #ffffff;
  text-decoration: none;
}

[data-theme="dark"] .widget-action-link {
  background-color: rgba(37, 99, 235, 0.25);
  color: #93c5fd;
}

[data-theme="dark"] .widget-action-link:hover {
  background-color: #2563eb;
  color: #ffffff;
}

/* Features Grid */
.trust-features-section {
  padding: 48px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

@media (min-width: 640px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.feature-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

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

.feature-icon-box {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background-color: var(--bg-card-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 16px;
  border: 1px solid var(--border-subtle);
}

.feature-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.feature-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* Tools Directory Grid */
.tools-suite-section {
  padding: 48px 0;
  background-color: var(--bg-card-subtle);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.section-header-centered {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 40px;
}

.section-title {
  font-size: clamp(1.6rem, 2.5vw, 2.1rem);
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.tools-directory-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 640px) {
  .tools-directory-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .tools-directory-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.tool-directory-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

.tool-directory-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--brand-primary);
}

.tool-directory-card.featured-card {
  border-color: var(--brand-primary);
  background: linear-gradient(180deg, var(--bg-card) 0%, var(--brand-primary-light) 150%);
}

[data-theme="dark"] .tool-directory-card.featured-card {
  background: linear-gradient(180deg, var(--bg-card) 0%, rgba(37, 99, 235, 0.15) 150%);
}

.tool-card-badge {
  position: absolute;
  top: 18px;
  right: 18px;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background-color: var(--brand-primary);
  color: #ffffff;
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.tool-card-icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.tool-card-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
  line-height: 1.3;
}

.tool-card-desc {
  font-size: 0.925rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 18px;
  flex: 1;
}

.tool-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 20px;
}

.tag {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
}

.tool-card-cta {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--brand-primary);
  text-decoration: none;
  padding-top: 14px;
  border-top: 1px solid var(--border-subtle);
  transition: all var(--transition-fast);
}

.tool-card-cta .arrow {
  transition: transform var(--transition-fast);
}

.tool-directory-card:hover .tool-card-cta .arrow {
  transform: translateX(4px);
}

/* Home Guide Section */
.home-guide-section {
  padding: 56px 0;
}

.guide-content-wrapper {
  max-width: 920px;
  margin: 0 auto;
}

.guide-columns-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  margin-top: 32px;
}

@media (min-width: 768px) {
  .guide-columns-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.guide-col {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 28px;
}

.guide-col-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.guide-col-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 14px;
}

.guide-col-list {
  padding-left: 20px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Editorial Banner */
.editorial-banner {
  background: linear-gradient(135deg, var(--brand-primary-light), var(--bg-card));
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-xl);
  padding: 28px 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  align-items: flex-start;
}

@media (min-width: 768px) {
  .editorial-banner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

[data-theme="dark"] .editorial-banner {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.15), var(--bg-card));
}

.editorial-icon {
  font-size: 2.2rem;
  flex-shrink: 0;
}

.editorial-text h4 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.editorial-text p {
  font-size: 0.925rem;
  color: var(--text-secondary);
  line-height: 1.55;
  margin: 0;
}

.tool-cta-banner {
  margin-top: 48px;
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  align-items: flex-start;
}

@media (min-width: 768px) {
  .tool-cta-banner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

.tool-cta-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.tool-cta-content p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin: 0;
}

/* --------------------------------------------------------------------------
   Hero & Tool Section
   -------------------------------------------------------------------------- */
.hero-section {
  padding: clamp(20px, 3vw, 40px) 0 clamp(16px, 2.5vw, 28px);
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--brand-primary);
  background-color: var(--brand-primary-light);
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

[data-theme="dark"] .hero-badge {
  color: #93c5fd;
  background-color: rgba(37, 99, 235, 0.25);
}

.hero-title {
  font-size: clamp(2rem, 4vw + 0.8rem, 3.1rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  max-width: 920px;
  margin: 0 auto 16px;
}

.hero-subtitle {
  font-size: clamp(1rem, 1.3vw + 0.5rem, 1.2rem);
  color: var(--text-secondary);
  max-width: 760px;
  margin: 0 auto 28px;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   Calculator Layout (App Card)
   -------------------------------------------------------------------------- */
.calculator-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
  margin-bottom: 48px;
  display: grid;
  grid-template-columns: 1fr;
  transition: box-shadow var(--transition-base), border-color var(--transition-base);
}

@media (min-width: 992px) {
  .calculator-card {
    grid-template-columns: 1.15fr 1fr;
  }
}

.calc-input-panel {
  padding: clamp(20px, 3vw, 36px);
  border-bottom: 1px solid var(--border-subtle);
}

@media (min-width: 992px) {
  .calc-input-panel {
    border-bottom: none;
    border-right: 1px solid var(--border-subtle);
  }
}

.calc-result-panel {
  padding: clamp(20px, 3vw, 36px);
  background-color: var(--bg-card-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

/* Pediatric & Clinical Notices */
.pediatric-notice {
  display: none;
  background-color: #eff6ff;
  border-left: 4px solid #3b82f6;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 12px 16px;
  margin-bottom: 18px;
  font-size: 0.875rem;
  color: #1e40af;
  line-height: 1.5;
}

[data-theme="dark"] .pediatric-notice {
  background-color: rgba(30, 58, 138, 0.35);
  border-left-color: #60a5fa;
  color: #bfdbfe;
}

.pediatric-notice.visible {
  display: block;
}

/* Unit Switch Tabs */
.unit-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  background-color: var(--bg-card-subtle);
  padding: 6px;
  border-radius: var(--radius-lg);
  margin-bottom: 24px;
  border: 1px solid var(--border-subtle);
}

.tab-btn {
  padding: 10px 16px;
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.tab-btn.active {
  background-color: var(--bg-surface);
  color: var(--brand-primary);
  box-shadow: var(--shadow-sm);
}

/* Form Controls */
.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.label-hint {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--text-muted);
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.form-input {
  width: 100%;
  height: 48px;
  padding: 0 54px 0 16px;
  font-size: 1rem;
  color: var(--text-primary);
  background-color: var(--bg-input);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.input-unit {
  position: absolute;
  right: 16px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  pointer-events: none;
}

.input-row-dual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

/* Gender Toggle */
.gender-toggle-group {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 8px;
}

.gender-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 12px;
  background-color: var(--bg-input);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.gender-btn:hover {
  background-color: var(--bg-hover);
}

.gender-btn.active {
  border-color: var(--brand-primary);
  background-color: var(--brand-primary-light);
  color: var(--brand-primary);
  font-weight: 600;
}

[data-theme="dark"] .gender-btn.active {
  background-color: rgba(37, 99, 235, 0.2);
  color: #60a5fa;
}

/* Field Error Alerts */
.field-error {
  display: none;
  font-size: 0.8rem;
  color: #dc2626;
  margin-top: 6px;
}

.field-error.visible {
  display: block;
}

.form-input.has-error {
  border-color: #dc2626;
}

/* Buttons */
.btn-group {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  margin-top: 24px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 48px;
  padding: 0 24px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background-color: var(--brand-primary);
  color: #ffffff;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background-color: var(--brand-primary-hover);
  box-shadow: var(--shadow-lg);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-surface);
  color: var(--text-secondary);
  border: 1px solid var(--border-medium);
}

.btn-secondary:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

/* --------------------------------------------------------------------------
   Calculator Results Panel
   -------------------------------------------------------------------------- */
.results-header {
  text-align: center;
  margin-bottom: 20px;
}

.results-eyebrow {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.bmi-number-display {
  font-size: clamp(2.8rem, 5vw, 4rem);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 12px;
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 6px;
}

.bmi-unit {
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--text-muted);
}

.category-badge {
  display: inline-block;
  padding: 8px 18px;
  font-size: 0.95rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  color: #ffffff;
  background-color: var(--color-normal);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

/* Gauge / Visual Meter */
.gauge-wrapper {
  margin: 20px 0 24px;
}

.gauge-bar-track {
  position: relative;
  height: 16px;
  border-radius: var(--radius-full);
  background: linear-gradient(
    to right,
    var(--color-severe-thin) 0%,
    var(--color-underweight) 15%,
    var(--color-normal) 25%,
    var(--color-normal) 45%,
    var(--color-overweight) 60%,
    var(--color-obese1) 75%,
    var(--color-obese2) 88%,
    var(--color-obese3) 100%
  );
  box-shadow: inset 0 2px 4px rgba(0,0,0,0.15);
}

.gauge-needle {
  position: absolute;
  top: -8px;
  left: 31.8%;
  transform: translateX(-50%);
  width: 14px;
  height: 32px;
  background-color: var(--text-primary);
  border: 3px solid var(--bg-surface);
  border-radius: 4px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.3);
  transition: left 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.gauge-needle::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 50%;
  transform: translateX(-50%);
  border-width: 6px 5px 0 5px;
  border-style: solid;
  border-color: var(--text-primary) transparent transparent transparent;
}

.gauge-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
}

/* Results Data Grid */
.results-meta-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 20px;
}

.meta-box {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 12px 14px;
}

.meta-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: 4px;
}

.meta-value {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

.meta-sub {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* Result Action Tools */
.results-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.action-btn-sm {
  padding: 10px;
  font-size: 0.85rem;
  font-weight: 600;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  transition: all var(--transition-fast);
}

.action-btn-sm:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
  border-color: var(--brand-primary);
}

/* Toast Notification */
.toast-msg {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 100;
  background-color: #0f172a;
  color: #ffffff;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  font-size: 0.9rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 8px;
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: opacity 0.25s, transform 0.25s;
}

.toast-msg.show {
  opacity: 1;
  transform: translateY(0);
}

/* --------------------------------------------------------------------------
   Rich SEO Content & Article Typography
   -------------------------------------------------------------------------- */
.seo-article {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: clamp(24px, 5vw, 56px);
  box-shadow: var(--shadow-sm);
  margin-bottom: 48px;
}

.article-header {
  border-bottom: 2px solid var(--border-subtle);
  padding-bottom: 24px;
  margin-bottom: 32px;
}

.article-title {
  font-size: clamp(1.75rem, 3vw, 2.3rem);
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.25;
  margin-bottom: 12px;
}

.author-byline {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.85rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.author-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background-color: var(--brand-primary-light);
  color: var(--brand-primary);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  font-weight: 600;
}

[data-theme="dark"] .author-badge {
  background-color: rgba(37, 99, 235, 0.25);
  color: #93c5fd;
}

/* Section Headings */
.seo-section {
  margin-bottom: 48px;
}

.seo-section:last-child {
  margin-bottom: 0;
}

.section-h2 {
  font-size: clamp(1.35rem, 2.5vw, 1.8rem);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 16px;
  line-height: 1.3;
}

.section-h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 24px 0 12px;
}

.article-p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 20px;
}

/* Formula Presentation Cards */
.formula-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin: 24px 0;
}

@media (min-width: 768px) {
  .formula-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.formula-card {
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.formula-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.formula-math {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--brand-primary);
  background-color: var(--bg-surface);
  border: 1px dashed var(--border-medium);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  margin-bottom: 14px;
}

/* Data Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
  margin: 24px 0;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
}

.health-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

.health-table th {
  background-color: var(--bg-card-subtle);
  color: var(--text-primary);
  font-weight: 700;
  padding: 14px 18px;
  border-bottom: 2px solid var(--border-subtle);
}

.health-table td {
  padding: 14px 18px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-subtle);
}

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

.health-table tr:hover td {
  background-color: var(--bg-hover);
}

.badge-cell {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
}

.dot-indicator {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

/* Callout Box */
.callout-box {
  background-color: var(--bg-card-subtle);
  border-left: 4px solid var(--brand-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 20px 24px;
  margin: 24px 0;
}

.callout-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

/* Steps Grid */
.steps-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: 24px 0;
}

@media (min-width: 768px) {
  .steps-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.step-card {
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.step-number {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background-color: var(--brand-primary);
  color: #ffffff;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  margin-bottom: 12px;
}

.step-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

/* FAQ Accordion */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 24px;
}

.faq-item {
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--bg-surface);
  transition: border-color var(--transition-fast);
}

.faq-item:hover {
  border-color: var(--border-medium);
}

.faq-question {
  width: 100%;
  padding: 18px 20px;
  background: none;
  border: none;
  text-align: left;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  gap: 12px;
}

.faq-icon {
  font-size: 1.25rem;
  font-weight: 400;
  transition: transform var(--transition-fast);
  color: var(--brand-primary);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  padding: 0 20px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  padding-bottom: 20px;
}

/* --------------------------------------------------------------------------
   Hub & All-Tools Page
   -------------------------------------------------------------------------- */
.tools-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin: 32px 0;
}

@media (min-width: 768px) {
  .tools-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.tool-hub-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
}

.tool-hub-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--brand-primary);
}

.tool-badge {
  display: inline-block;
  padding: 4px 10px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  border-radius: var(--radius-full);
  background-color: var(--brand-primary-light);
  color: var(--brand-primary);
  margin-bottom: 12px;
}

[data-theme="dark"] .tool-badge {
  background-color: rgba(37, 99, 235, 0.25);
  color: #93c5fd;
}

.tool-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.tool-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
  line-height: 1.6;
}

.mini-tool-box {
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 20px;
}

/* --------------------------------------------------------------------------
   Contact, About & Legal Pages
   -------------------------------------------------------------------------- */
.contact-form {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: clamp(24px, 4vw, 40px);
  box-shadow: var(--shadow-md);
}

.team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin: 32px 0;
}

@media (min-width: 768px) {
  .team-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.team-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
}

.team-avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: linear-gradient(135deg, #2563eb, #38bdf8);
  color: #ffffff;
  font-size: 1.5rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}

/* --------------------------------------------------------------------------
   Site Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  padding: 56px 0 32px;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
  }
}

.footer-brand p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 14px 0 20px;
  line-height: 1.6;
}

.footer-heading {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

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

.footer-disclaimer-card {
  background-color: var(--bg-card-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin-bottom: 32px;
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-top: 1px solid var(--border-subtle);
  padding-top: 24px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
  }
}

/* --------------------------------------------------------------------------
   Mobile Navigation Responsive Behavior
   -------------------------------------------------------------------------- */
@media (max-width: 880px) {
  .site-nav {
    display: none;
  }

  .mobile-menu-btn {
    display: flex;
  }
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
  z-index: 999;
  background: var(--brand-primary);
  color: #ffffff;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
}

.skip-link:focus {
  position: fixed;
  top: 10px;
  left: 10px;
  width: auto;
  height: auto;
  outline: 2px solid #ffffff;
}

/* --------------------------------------------------------------------------
   Print Stylesheet
   -------------------------------------------------------------------------- */
@media print {
  .site-header, .site-footer, .btn-group, .results-actions, .theme-toggle-btn, .mobile-menu-btn, .faq-list, .breadcrumbs {
    display: none !important;
  }

  body {
    background: #ffffff !important;
    color: #000000 !important;
    font-size: 12pt;
  }

  .calculator-card {
    border: 1px solid #000000 !important;
    box-shadow: none !important;
    display: block !important;
  }

  .calc-result-panel {
    background: #f8fafc !important;
    padding: 20px !important;
  }

  .category-badge {
    border: 1px solid #000000 !important;
    color: #000000 !important;
    background: #e2e8f0 !important;
  }
}