/* ==========================================================================
   DESA55 Official Stylesheet (https://indee.co.in/)
   Semantic-first, Performance-first, Mobile-first, Accessibility WCAG 2.2 AA
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Custom Properties / Design Tokens
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette - Light Theme */
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-surface-subtle: #f1f5f9;
  --color-surface-elevated: #ffffff;
  --color-border: #e2e8f0;
  --color-border-hover: #cbd5e1;

  --color-text-main: #0f172a;
  --color-text-muted: #475569;
  --color-text-subtle: #64748b;
  --color-text-inverse: #ffffff;

  /* Brand Accents */
  --color-brand-primary: #1d4ed8;
  --color-brand-primary-hover: #1e40af;
  --color-brand-secondary: #0d9488;
  --color-brand-accent: #f59e0b;
  --color-brand-gradient: linear-gradient(135deg, #1d4ed8 0%, #0d9488 100%);
  --color-brand-gradient-subtle: linear-gradient(135deg, rgba(29, 78, 216, 0.06) 0%, rgba(13, 148, 136, 0.06) 100%);
  
  /* Status Colors */
  --color-success: #15803d;
  --color-success-bg: #f0fdf4;
  --color-warning: #b45309;
  --color-warning-bg: #fffbeb;
  --color-info: #0369a1;
  --color-info-bg: #f0f9ff;

  /* 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;

  --fs-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.8125rem);
  --fs-sm: clamp(0.875rem, 0.825rem + 0.25vw, 0.9375rem);
  --fs-base: clamp(1rem, 0.95rem + 0.25vw, 1.0625rem);
  --fs-md: clamp(1.125rem, 1.05rem + 0.35vw, 1.25rem);
  --fs-lg: clamp(1.25rem, 1.15rem + 0.5vw, 1.5rem);
  --fs-xl: clamp(1.5rem, 1.35rem + 0.75vw, 1.875rem);
  --fs-2xl: clamp(1.875rem, 1.6rem + 1.25vw, 2.375rem);
  --fs-3xl: clamp(2.25rem, 1.85rem + 2vw, 3rem);

  --lh-tight: 1.2;
  --lh-snug: 1.35;
  --lh-normal: 1.5;
  --lh-relaxed: 1.7;

  /* Spacing */
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4.5rem;

  /* Layout */
  --container-max: 1200px;
  --container-narrow: 840px;
  --header-height: 4.25rem;
  --radius-sm: 0.375rem;
  --radius-md: 0.625rem;
  --radius-lg: 1rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-glow: 0 0 20px rgba(29, 78, 216, 0.15);

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

/* Dark Mode Preference Support */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #090d16;
    --color-surface: #111827;
    --color-surface-subtle: #1f2937;
    --color-surface-elevated: #1e293b;
    --color-border: #334155;
    --color-border-hover: #475569;

    --color-text-main: #f8fafc;
    --color-text-muted: #cbd5e1;
    --color-text-subtle: #94a3b8;

    --color-brand-primary: #3b82f6;
    --color-brand-primary-hover: #60a5fa;
    --color-brand-secondary: #14b8a6;
    --color-brand-gradient-subtle: linear-gradient(135deg, rgba(59, 130, 246, 0.12) 0%, rgba(20, 184, 166, 0.12) 100%);

    --color-success: #4ade80;
    --color-success-bg: rgba(74, 222, 128, 0.1);
    --color-warning: #fbbf24;
    --color-warning-bg: rgba(251, 191, 36, 0.1);
    --color-info: #38bdf8;
    --color-info-bg: rgba(56, 189, 248, 0.1);

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
  }
}

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

html {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: var(--lh-normal);
  color: var(--color-text-main);
  background-color: var(--color-bg);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

a:hover {
  color: var(--color-brand-primary-hover);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

button {
  background: none;
  border: none;
  cursor: pointer;
}

/* Accessibility Focus States */
:focus-visible {
  outline: 2px solid var(--color-brand-primary);
  outline-offset: 3px;
}

/* Skip to main content link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 9999;
  background: var(--color-brand-primary);
  color: var(--color-text-inverse);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-weight: 600;
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 1rem;
}

/* --------------------------------------------------------------------------
   3. Typography & Headings (Strict Hierarchy)
   -------------------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-text-main);
  font-weight: 700;
  line-height: var(--lh-tight);
}

h1 {
  font-size: var(--fs-3xl);
  letter-spacing: -0.025em;
  margin-bottom: var(--space-md);
}

h2 {
  font-size: var(--fs-2xl);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-sm);
}

h3 {
  font-size: var(--fs-xl);
  letter-spacing: -0.015em;
  margin-bottom: var(--space-xs);
}

h4 {
  font-size: var(--fs-lg);
  margin-bottom: var(--space-xs);
}

p {
  color: var(--color-text-muted);
  line-height: var(--lh-relaxed);
  margin-bottom: var(--space-md);
  font-size: var(--fs-base);
}

p.lead {
  font-size: var(--fs-md);
  color: var(--color-text-main);
  line-height: var(--lh-snug);
}

strong {
  color: var(--color-text-main);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   4. Layout & Containers
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-md);
  padding-right: var(--space-md);
}

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

.section {
  padding-top: var(--space-2xl);
  padding-bottom: var(--space-2xl);
}

@media (min-width: 768px) {
  .section {
    padding-top: var(--space-3xl);
    padding-bottom: var(--space-3xl);
  }
}

.section-subtle {
  background-color: var(--color-surface-subtle);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: var(--space-2xl);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  background: var(--color-brand-gradient-subtle);
  color: var(--color-brand-primary);
  border: 1px solid var(--color-border);
  padding: var(--space-2xs) var(--space-sm);
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

/* --------------------------------------------------------------------------
   5. Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  transition: background-color var(--transition-normal);
}

@media (prefers-color-scheme: dark) {
  .site-header {
    background-color: rgba(17, 24, 39, 0.95);
  }
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.brand-link {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  line-height: 1;
}

.brand-link:hover {
  text-decoration: none;
}

.brand-logo-img {
  height: 42px;
  width: auto;
  max-width: 175px;
  object-fit: contain;
  display: block;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.brand-link:hover .brand-logo-img {
  opacity: 0.92;
  transform: translateY(-1px);
}

@media (max-width: 480px) {
  .brand-logo-img {
    height: 36px;
    max-width: 145px;
  }
}

@media (prefers-color-scheme: dark) {
  .brand-logo-img {
    background: rgba(255, 255, 255, 0.95);
    padding: 3px 8px;
    border-radius: var(--radius-sm);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.25);
  }
}

.nav-desktop {
  display: none;
}

@media (min-width: 900px) {
  .nav-desktop {
    display: flex;
    align-items: center;
    gap: var(--space-md);
  }
}

.nav-list {
  display: flex;
  list-style: none;
  gap: var(--space-xs);
}

.nav-item-link {
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: var(--fs-sm);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  text-decoration: none;
}

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

.nav-item-link[aria-current="page"] {
  color: var(--color-brand-primary);
  background-color: var(--color-brand-gradient-subtle);
  font-weight: 600;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  color: var(--color-text-main);
  background: var(--color-surface);
}

@media (min-width: 900px) {
  .mobile-menu-toggle {
    display: none;
  }
}

/* Mobile Drawer */
.mobile-nav-drawer {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-lg) var(--space-md);
  display: none;
  flex-direction: column;
  gap: var(--space-md);
  overflow-y: auto;
  z-index: 999;
}

.mobile-nav-drawer.is-open {
  display: flex;
}

.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.mobile-nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-weight: 500;
  color: var(--color-text-main);
  background-color: var(--color-surface-subtle);
  text-decoration: none;
  font-size: var(--fs-base);
}

.mobile-nav-link:hover,
.mobile-nav-link[aria-current="page"] {
  background-color: var(--color-brand-primary);
  color: var(--color-text-inverse);
  text-decoration: none;
}

/* --------------------------------------------------------------------------
   6. Buttons & CTAs
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  min-height: 44px;
  padding: var(--space-xs) var(--space-lg);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: var(--fs-sm);
  line-height: 1;
  text-decoration: none;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: 1px solid transparent;
}

.btn-primary {
  background-color: var(--color-brand-primary);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background-color: var(--color-brand-primary-hover);
  color: var(--color-text-inverse);
  text-decoration: none;
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background-color: var(--color-surface);
  color: var(--color-text-main);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  background-color: var(--color-surface-subtle);
  border-color: var(--color-border-hover);
  color: var(--color-text-main);
  text-decoration: none;
}

.btn-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
}

/* --------------------------------------------------------------------------
   7. Breadcrumb Navigation
   -------------------------------------------------------------------------- */
.breadcrumb-wrapper {
  padding-top: var(--space-sm);
  padding-bottom: var(--space-sm);
  background-color: var(--color-surface-subtle);
  border-bottom: 1px solid var(--color-border);
  font-size: var(--fs-xs);
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  list-style: none;
  gap: var(--space-xs);
  color: var(--color-text-subtle);
}

.breadcrumb-item {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.breadcrumb-item a {
  color: var(--color-text-subtle);
  text-decoration: none;
}

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

.breadcrumb-separator {
  user-select: none;
  color: var(--color-text-subtle);
  font-size: 0.75rem;
}

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

/* --------------------------------------------------------------------------
   8. Hero Section
   -------------------------------------------------------------------------- */
.hero {
  padding-top: var(--space-2xl);
  padding-bottom: var(--space-3xl);
  background: var(--color-brand-gradient-subtle);
  border-bottom: 1px solid var(--color-border);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
  align-items: center;
}

@media (min-width: 992px) {
  .hero-grid {
    grid-template-columns: 1.15fr 0.85fr;
  }
}

.hero-content h1 {
  font-size: var(--fs-3xl);
  margin-bottom: var(--space-md);
}

.hero-lead {
  font-size: var(--fs-md);
  color: var(--color-text-muted);
  line-height: var(--lh-relaxed);
  margin-bottom: var(--space-lg);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.stat-item-number {
  font-size: var(--fs-xl);
  font-weight: 800;
  color: var(--color-brand-primary);
  line-height: 1;
}

.stat-item-label {
  font-size: var(--fs-xs);
  color: var(--color-text-subtle);
  margin-top: var(--space-2xs);
  line-height: var(--lh-snug);
}

.hero-visual-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-lg);
}

.hero-visual-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-md);
}

.window-dots {
  display: flex;
  gap: 6px;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: var(--radius-full);
}
.dot-red { background-color: #ef4444; }
.dot-yellow { background-color: #f59e0b; }
.dot-green { background-color: #10b981; }

.visual-preview-box {
  background: var(--color-surface-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-md);
}

/* --------------------------------------------------------------------------
   9. Cards & Grids
   -------------------------------------------------------------------------- */
.cards-grid-4 {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

@media (min-width: 640px) {
  .cards-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

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

@media (min-width: 640px) {
  .cards-grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.cards-grid-2 {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

@media (min-width: 768px) {
  .cards-grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }
}

.card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
  display: flex;
  flex-direction: column;
}

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

.card-icon-wrapper {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--color-brand-gradient-subtle);
  color: var(--color-brand-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-md);
  border: 1px solid var(--color-border);
}

.card-icon-wrapper svg {
  width: 24px;
  height: 24px;
}

.card h3 {
  font-size: var(--fs-md);
  margin-bottom: var(--space-xs);
}

.card p {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  flex-grow: 1;
}

.card-link {
  font-size: var(--fs-sm);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2xs);
  color: var(--color-brand-primary);
}

/* --------------------------------------------------------------------------
   10. Multi-Device Experience Grid
   -------------------------------------------------------------------------- */
.device-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

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

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

.device-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-sm);
}

.device-tag {
  background: var(--color-surface-subtle);
  color: var(--color-text-subtle);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  font-weight: 600;
  border: 1px solid var(--color-border);
}

.device-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

.device-list li {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  display: flex;
  align-items: flex-start;
  gap: var(--space-xs);
}

.device-list li::before {
  content: "✓";
  color: var(--color-brand-secondary);
  font-weight: bold;
}

/* --------------------------------------------------------------------------
   11. Steps / Onboarding Flow
   -------------------------------------------------------------------------- */
.steps-container {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

@media (min-width: 768px) {
  .steps-container {
    grid-template-columns: repeat(4, 1fr);
  }
}

.step-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  position: relative;
}

.step-number {
  font-size: var(--fs-xs);
  font-weight: 800;
  color: var(--color-brand-primary);
  background: var(--color-brand-gradient-subtle);
  border: 1px solid var(--color-border);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-sm);
}

/* --------------------------------------------------------------------------
   12. FAQ Accordion (Semantic Details/Summary & Accessible Controls)
   -------------------------------------------------------------------------- */
.faq-wrapper {
  max-width: 840px;
  margin-left: auto;
  margin-right: auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

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

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

.faq-question {
  width: 100%;
  text-align: left;
  padding: var(--space-md) var(--space-lg);
  font-size: var(--fs-base);
  font-weight: 600;
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  cursor: pointer;
  background: none;
}

.faq-question:focus-visible {
  outline: 2px solid var(--color-brand-primary);
  outline-offset: -2px;
}

.faq-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.faq-item.is-open .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 var(--space-lg) var(--space-md);
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-relaxed);
  display: none;
}

.faq-item.is-open .faq-answer {
  display: block;
}

/* --------------------------------------------------------------------------
   13. Content Box / Trust / Callout
   -------------------------------------------------------------------------- */
.callout-box {
  background: var(--color-surface);
  border-left: 4px solid var(--color-brand-primary);
  border-top: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
}

.callout-box.info {
  border-left-color: var(--color-brand-primary);
  background: var(--color-brand-gradient-subtle);
}

.callout-box.warning {
  border-left-color: var(--color-warning);
  background: var(--color-warning-bg);
}

.callout-title {
  font-weight: 700;
  font-size: var(--fs-base);
  color: var(--color-text-main);
  margin-bottom: var(--space-xs);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

/* --------------------------------------------------------------------------
   14. Article / Long-form Content Layout
   -------------------------------------------------------------------------- */
.article-header {
  margin-bottom: var(--space-2xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid var(--color-border);
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-md);
  color: var(--color-text-subtle);
  font-size: var(--fs-sm);
  margin-top: var(--space-sm);
}

.author-box {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-top: var(--space-2xl);
}

.author-avatar {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-full);
  background: var(--color-brand-gradient-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: var(--color-brand-primary);
  font-size: var(--fs-lg);
  flex-shrink: 0;
  border: 1px solid var(--color-border);
}

.toc-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.toc-title {
  font-weight: 700;
  font-size: var(--fs-base);
  margin-bottom: var(--space-sm);
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  padding-left: var(--space-xs);
}

.toc-list a {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
}

.toc-list a:hover {
  color: var(--color-brand-primary);
}

/* --------------------------------------------------------------------------
   15. Site Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  margin-top: auto;
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-xl);
}

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

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

@media (min-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
  }
}

.footer-brand p {
  font-size: var(--fs-sm);
  color: var(--color-text-subtle);
  margin-top: var(--space-sm);
  max-width: 320px;
}

.footer-heading {
  font-size: var(--fs-sm);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-main);
  margin-bottom: var(--space-md);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.footer-links a {
  color: var(--color-text-muted);
  font-size: var(--fs-sm);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  align-items: center;
  justify-content: space-between;
  font-size: var(--fs-xs);
  color: var(--color-text-subtle);
  text-align: center;
}

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

/* --------------------------------------------------------------------------
   16. Utilities
   -------------------------------------------------------------------------- */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mb-none { margin-bottom: 0; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}