/* ============================================
   CSS VARIABLES & RESET
   ============================================ */

:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-dark: #1e40af;
  --color-primary-light: #3b82f6;
  --color-secondary: #10b981;
  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-600: #4b5563;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;
  --color-white: #ffffff;
  --color-text: #1f2937;
  --color-border: #e5e7eb;
  --color-shadow: rgba(0, 0, 0, 0.1);

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', sans-serif;
  --font-size-base: 16px;
  --font-size-sm: 14px;
  --font-size-lg: 18px;
  --font-size-xl: 20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 32px;
  --font-size-4xl: 48px;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;

  /* Other */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --transition: all 0.3s ease;
  --max-width: 1280px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-white);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: var(--font-size-4xl);
}

h2 {
  font-size: var(--font-size-3xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

h4 {
  font-size: var(--font-size-xl);
}

p {
  margin-bottom: var(--spacing-md);
}

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

a:hover {
  color: var(--color-primary-dark);
}

a:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ============================================
   LAYOUT
   ============================================ */

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.header {
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 3px var(--color-shadow);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md);
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  text-decoration: none;
}

.logo-icon {
  height: 48px;
  width: auto;
}

.logo-text {
  height: 48px;
  width: auto;
}

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

.nav a {
  font-weight: 500;
  color: var(--color-text);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.nav a:hover {
  background-color: var(--color-gray-100);
  color: var(--color-primary);
}

.nav a.active {
  color: var(--color-primary);
  background-color: var(--color-gray-100);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
  color: var(--color-text);
}

.nav-toggle-icon {
  display: block;
  width: 22px;
  height: 2px;
  background-color: currentColor;
  position: relative;
  transition: var(--transition);
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: '';
  display: block;
  width: 22px;
  height: 2px;
  background-color: currentColor;
  position: absolute;
  transition: var(--transition);
}

.nav-toggle-icon::before { top: -7px; }
.nav-toggle-icon::after  { top: 7px; }

.nav-toggle[aria-expanded="true"] .nav-toggle-icon {
  background-color: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  transform: rotate(45deg);
  top: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after {
  transform: rotate(-45deg);
  top: 0;
}

.footer {
  background-color: var(--color-gray-900);
  color: var(--color-white);
  padding: var(--spacing-2xl) var(--spacing-md);
  margin-top: var(--spacing-3xl);
  text-align: center;
}

.footer-content {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer p {
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-sm);
}

.footer a {
  color: var(--color-gray-300);
}

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

main {
  min-height: calc(100vh - 200px);
}

/* ============================================
   HERO SECTION
   ============================================ */

.hero {
  background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-primary) 100%);
  color: var(--color-white);
  padding: var(--spacing-3xl) var(--spacing-md);
  text-align: center;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  margin-bottom: var(--spacing-md);
  color: var(--color-white);
}

.hero p {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-lg);
  color: rgba(255, 255, 255, 0.9);
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  background-color: var(--color-primary);
  color: var(--color-white);
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

.btn:hover {
  background-color: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn:focus {
  outline: 2px solid var(--color-primary-dark);
  outline-offset: 2px;
}

.btn-secondary {
  background-color: var(--color-secondary);
}

.btn-secondary:hover {
  background-color: #059669;
}

/* ============================================
   GRID LAYOUTS
   ============================================ */

.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

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

  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-3 {
    grid-template-columns: repeat(3, 1fr);
  }

  .grid-4 {
    grid-template-columns: repeat(4, 1fr);
  }

  .nav {
    gap: var(--spacing-2xl);
  }
}

/* ============================================
   CARDS
   ============================================ */

.card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
}

.card:hover {
  box-shadow: 0 10px 25px var(--color-shadow);
  transform: translateY(-4px);
}

.card-image {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  display: block;
  background-color: var(--color-gray-100);
}

/* ============================================
   CAROUSEL
   ============================================ */

.carousel {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  overflow: hidden;
  background-color: var(--color-gray-100);
}

.carousel-track {
  display: flex;
  height: 100%;
  transition: transform 0.3s ease;
}

.carousel-slide {
  min-width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.carousel-slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background-color: rgba(0, 0, 0, 0.5);
  color: var(--color-white);
  border: none;
  padding: var(--spacing-md);
  font-size: var(--font-size-lg);
  cursor: pointer;
  z-index: 10;
  transition: background-color var(--transition);
}

.carousel-btn:hover {
  background-color: rgba(0, 0, 0, 0.8);
}

.carousel-btn:focus {
  outline: 2px solid var(--color-white);
  outline-offset: -2px;
}

.carousel-prev {
  left: 0;
}

.carousel-next {
  right: 0;
}

.carousel-dots {
  position: absolute;
  bottom: var(--spacing-md);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: var(--spacing-sm);
  z-index: 10;
}

.carousel-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.5);
  border: none;
  cursor: pointer;
  transition: background-color var(--transition);
  padding: 0;
}

.carousel-dot:hover {
  background-color: rgba(255, 255, 255, 0.8);
}

.carousel-dot.active {
  background-color: var(--color-white);
}

.carousel-dot:focus {
  outline: 2px solid var(--color-white);
  outline-offset: 2px;
}

.card-content {
  padding: var(--spacing-lg);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.card-description {
  font-size: var(--font-size-sm);
  color: var(--color-gray-600);
  margin-bottom: var(--spacing-md);
  line-height: var(--line-height-relaxed);
}

.card-price {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.card-specs {
  font-size: var(--font-size-sm);
  color: var(--color-gray-600);
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
}

.spec-item {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.spec-label {
  font-weight: 500;
  min-width: 70px;
}

.card-status {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 500;
  margin-bottom: var(--spacing-md);
}

.status-in-stock {
  background-color: #dbeafe;
  color: #0c4a6e;
}

.status-out-of-stock {
  background-color: #fee2e2;
  color: #7f1d1d;
}

/* ============================================
   SECTIONS
   ============================================ */

.section {
  padding: var(--spacing-3xl) var(--spacing-md);
}

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
}

.section-title h2 {
  margin-bottom: var(--spacing-md);
}

.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-gray-600);
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================
   BREADCRUMB
   ============================================ */

.breadcrumb {
  display: flex;
  gap: var(--spacing-sm);
  font-size: var(--font-size-sm);
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-lg) var(--spacing-md) 0;
}

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

.breadcrumb span {
  color: var(--color-gray-600);
}

/* ============================================
   RESPONSIVE TYPOGRAPHY
   ============================================ */

@media (max-width: 640px) {
  h1 {
    font-size: var(--font-size-2xl);
  }

  h2 {
    font-size: var(--font-size-xl);
  }

  .hero {
    padding: var(--spacing-2xl) var(--spacing-md);
  }

  .hero h1 {
    font-size: var(--font-size-2xl);
  }

  .nav-toggle {
    display: block;
  }

  .nav {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 4px 6px var(--color-shadow);
    flex-direction: column;
    gap: 0;
    padding: var(--spacing-sm) 0;
    z-index: 99;
  }

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

  .nav li {
    width: 100%;
  }

  .nav a {
    display: block;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: 0;
  }
}

/* ============================================
   ACCESSIBILITY
   ============================================ */

/* Skip to main content link */
.skip-to-main {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: var(--color-white);
  padding: 8px;
  text-decoration: none;
  z-index: 100;
}

.skip-to-main:focus {
  top: 0;
}

/* Focus visible for better keyboard navigation */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: more) {
  :root {
    --color-gray-600: #2d3748;
    --color-gray-800: #0a0e27;
  }
}

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */

.text-center {
  text-align: center;
}

.text-muted {
  color: var(--color-gray-600);
}

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.p-md { padding: var(--spacing-md); }
.p-lg { padding: var(--spacing-lg); }