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

/* CSS Custom Properties (Design Tokens) */
:root {
  /* Colors */
  --color-primary: #2d5139;
  --color-primary-light: #4a6b56;
  --color-primary-dark: #1a3026;
  --color-secondary: #d3f5e2;
  --color-accent: #7dd3fc;
  --color-background: linear-gradient(135deg, #f0fdf4 0%, #ecfccb 50%, #d9f99d 100%);
  --color-surface: rgba(255, 255, 255, 0.8);
  --color-surface-elevated: rgba(255, 255, 255, 0.95);
  --color-text: #1f2937;
  --color-text-muted: #6b7280;
  --color-border: rgba(45, 81, 57, 0.1);
  
  /* Typography */
  --font-family-base: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-bold: 700;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  
  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  
  /* Radius */
  --radius-sm: 0.375rem;
  --radius-base: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-base: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Base Styles */
html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background: var(--color-background);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Utility Classes */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* Layout Components */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
}

.site-header {
  margin-bottom: var(--space-16);
  animation: fadeInUp var(--transition-slow) ease-out;
}

.site-title {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
  letter-spacing: -0.025em;
  text-shadow: 0 2px 4px rgba(45, 81, 57, 0.1);
}

.site-description {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-light);
  color: var(--color-text-muted);
  letter-spacing: 0.025em;
}

/* Products Section */
.products {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-8);
  max-width: 800px;
  margin: 0 auto;
}

/* Card Component */
.card {
  position: relative;
  background: var(--color-surface);
  backdrop-filter: blur(20px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-8);
  transition: all var(--transition-base);
  overflow: hidden;
  animation: fadeInUp var(--transition-slow) ease-out;
  animation-fill-mode: both;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(125, 211, 252, 0.1) 0%, rgba(45, 81, 57, 0.05) 100%);
  opacity: 0;
  transition: opacity var(--transition-base);
  pointer-events: none;
}

.card:hover::before {
  opacity: 1;
}

.card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: var(--shadow-xl);
  border-color: rgba(125, 211, 252, 0.3);
}

.card:focus-within {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.card-icon {
  margin-bottom: var(--space-6);
  display: flex;
  justify-content: center;
}

.card-icon img {
  width: 80px;
  height: 80px;
  object-fit: contain;
  filter: drop-shadow(0 4px 6px rgba(0, 0, 0, 0.1));
  transition: transform var(--transition-base);
}

.card:hover .card-icon img {
  transform: scale(1.1);
}

.card-content {
  margin-bottom: var(--space-6);
}

.card-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  margin-bottom: var(--space-2);
  letter-spacing: -0.025em;
}

.card-description {
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
}

.card-link {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  text-decoration: none;
  color: inherit;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: inherit;
  transition: all var(--transition-base);
}

.card-link:focus {
  outline: none;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Animation Delays */
.card:nth-child(1) { animation-delay: 100ms; }
.card:nth-child(2) { animation-delay: 200ms; }
.card:nth-child(3) { animation-delay: 300ms; }

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --font-size-5xl: 2.5rem;
    --font-size-2xl: 1.25rem;
    --space-16: 3rem;
    --space-8: 1.5rem;
  }
  
  body {
    padding: var(--space-2);
  }
  
  .products {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }
  
  .card {
    padding: var(--space-6);
  }
  
  .card-icon img {
    width: 64px;
    height: 64px;
  }
}

@media (max-width: 480px) {
  :root {
    --font-size-5xl: 2rem;
    --font-size-lg: 1rem;
  }
  
  .site-header {
    margin-bottom: var(--space-12);
  }
  
  .card {
    padding: var(--space-5);
  }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
  :root {
    --color-background: #ffffff;
    --color-surface: #ffffff;
    --color-border: #000000;
    --color-text: #000000;
    --color-text-muted: #333333;
  }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #4ade80;
    --color-primary-light: #6ee7b7;
    --color-primary-dark: #22c55e;
    --color-background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    --color-surface: rgba(15, 23, 42, 0.8);
    --color-surface-elevated: rgba(15, 23, 42, 0.95);
    --color-text: #f8fafc;
    --color-text-muted: #cbd5e1;
    --color-border: rgba(74, 222, 128, 0.2);
    --color-accent: #38bdf8;
  }
}