/* Material Design 3 CSS Variables */
:root {
  /* Primary Colors */
  --primary-color: #2E7D32;
  --primary-container: #A8DAB5;
  --on-primary: #FFFFFF;
  --on-primary-container: #002106;
  
  /* Secondary Colors */
  --secondary-color: #81C784;
  --secondary-container: #D7F8D8;
  --on-secondary: #FFFFFF;
  --on-secondary-container: #002106;
  
  /* Feature Colors */
  --yaku-color: #4CAF50;
  --calculator-color: #2196F3;
  --learning-color: #9C27B0;
  --practice-color: #FF5722;
  
  /* Surface Colors */
  --surface: #FFFFFF;
  --surface-variant: #F5F5F5;
  --surface-container: #F8F9FA;
  --surface-container-high: #ECECEC;
  --on-surface: #212121;
  --on-surface-variant: #757575;
  
  /* Background */
  --background: #FEFBFF;
  --on-background: #1C1B1F;
  
  /* Error */
  --error: #D32F2F;
  --error-container: #FFEBEE;
  --on-error: #FFFFFF;
  --on-error-container: #410E0B;
  
  /* Warning */
  --warning: #F57C00;
  --info: #1976D2;
  --success: #388E3C;
  
  /* Outline */
  --outline: #E0E0E0;
  --outline-variant: #F0F0F0;
  
  /* Shadow */
  --shadow: rgba(0, 0, 0, 0.1);
  --shadow-medium: rgba(0, 0, 0, 0.15);
  
  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-xxl: 48px;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-xxl: 24px;
  
  /* Typography */
  --font-family: 'SF Pro Display', 'Roboto', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  
  /* Typography Scale */
  --headline-large: 700 32px/40px var(--font-family);
  --headline-medium: 600 28px/36px var(--font-family);
  --headline-small: 600 24px/32px var(--font-family);
  --title-large: 600 20px/28px var(--font-family);
  --title-medium: 600 18px/24px var(--font-family);
  --title-small: 600 16px/24px var(--font-family);
  --body-large: 400 16px/24px var(--font-family);
  --body-medium: 400 14px/20px var(--font-family);
  --body-small: 400 12px/16px var(--font-family);
  --label-large: 500 14px/20px var(--font-family);
  --label-medium: 500 12px/16px var(--font-family);
  --label-small: 500 11px/16px var(--font-family);
  
  /* Elevation */
  --elevation-1: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
  --elevation-2: 0 3px 6px rgba(0, 0, 0, 0.16), 0 3px 6px rgba(0, 0, 0, 0.23);
  --elevation-3: 0 10px 20px rgba(0, 0, 0, 0.19), 0 6px 6px rgba(0, 0, 0, 0.23);
}

/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font: var(--body-large);
  color: var(--on-background);
  background-color: var(--background);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* App Bar */
.app-bar {
  background-color: var(--surface);
  border-bottom: 1px solid var(--outline-variant);
  padding: var(--spacing-md) 0;
}

.app-bar-content {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.app-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-lg);
  box-shadow: var(--elevation-1);
}

.app-title {
  font: var(--title-large);
  color: var(--on-surface);
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--surface) 0%, var(--surface-variant) 100%);
  padding: var(--spacing-xxl) 0;
  text-align: center;
}

.hero-content {
  max-width: 600px;
  margin: 0 auto;
}

.hero-icon {
  width: 120px;
  height: 120px;
  margin-bottom: var(--spacing-lg);
  border-radius: var(--radius-xxl);
  box-shadow: var(--elevation-3);
}

.hero-title {
  font: var(--headline-large);
  color: var(--primary-color);
  margin-bottom: var(--spacing-md);
}

.hero-subtitle {
  font: var(--body-large);
  color: var(--on-surface-variant);
  margin-bottom: var(--spacing-xl);
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

/* Download Buttons */
.download-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

.download-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--primary-color);
  color: var(--on-primary);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: all 0.2s ease;
  box-shadow: var(--elevation-2);
  min-width: 180px;
}

.download-btn:hover {
  background: color-mix(in srgb, var(--primary-color) 90%, black);
  transform: translateY(-2px);
  box-shadow: var(--elevation-3);
}

.download-btn .material-symbols-outlined {
  font-size: 24px;
}

.btn-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.btn-label {
  font: var(--label-small);
  opacity: 0.9;
}

.btn-store {
  font: var(--label-large);
  font-weight: 600;
}

.download-btn.android {
  background: var(--calculator-color);
}

.download-btn.android:hover {
  background: color-mix(in srgb, var(--calculator-color) 90%, black);
}

.download-btn.disabled {
  background: var(--on-surface-variant);
  opacity: 0.6;
  cursor: not-allowed;
  pointer-events: none;
}

/* Sections */
.features, .support {
  padding: var(--spacing-xxl) 0;
}

.section-title {
  font: var(--headline-medium);
  color: var(--on-surface);
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.feature-card {
  background: var(--surface);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
  box-shadow: var(--elevation-1);
  transition: all 0.2s ease;
  border: 1px solid var(--outline-variant);
  position: relative;
  overflow: hidden;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--elevation-3);
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--primary-color);
}

.feature-card.yaku::before { background: var(--yaku-color); }
.feature-card.calculator::before { background: var(--calculator-color); }
.feature-card.learning::before { background: var(--learning-color); }
.feature-card.practice::before { background: var(--practice-color); }

.feature-icon {
  width: 56px;
  height: 56px;
  background: var(--surface-container);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-md);
}

.feature-card.yaku .feature-icon { background: color-mix(in srgb, var(--yaku-color) 15%, transparent); }
.feature-card.calculator .feature-icon { background: color-mix(in srgb, var(--calculator-color) 15%, transparent); }
.feature-card.learning .feature-icon { background: color-mix(in srgb, var(--learning-color) 15%, transparent); }
.feature-card.practice .feature-icon { background: color-mix(in srgb, var(--practice-color) 15%, transparent); }

.feature-icon .material-symbols-outlined {
  font-size: 24px;
  color: var(--primary-color);
}

.feature-card.yaku .feature-icon .material-symbols-outlined { color: var(--yaku-color); }
.feature-card.calculator .feature-icon .material-symbols-outlined { color: var(--calculator-color); }
.feature-card.learning .feature-icon .material-symbols-outlined { color: var(--learning-color); }
.feature-card.practice .feature-icon .material-symbols-outlined { color: var(--practice-color); }

.feature-title {
  font: var(--title-medium);
  color: var(--on-surface);
  margin-bottom: var(--spacing-sm);
}

.feature-description {
  font: var(--body-medium);
  color: var(--on-surface-variant);
  margin-bottom: var(--spacing-md);
}

.feature-status {
  font: var(--label-medium);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-sm);
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.feature-status.available {
  background: color-mix(in srgb, var(--success) 15%, transparent);
  color: var(--success);
}

.feature-status.coming-soon {
  background: color-mix(in srgb, var(--warning) 15%, transparent);
  color: var(--warning);
}

/* Support Grid */
.support-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.support-card {
  background: var(--surface);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
  box-shadow: var(--elevation-1);
  transition: all 0.2s ease;
  border: 1px solid var(--outline-variant);
  text-align: center;
}

.support-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--elevation-2);
}

.support-icon {
  width: 64px;
  height: 64px;
  background: color-mix(in srgb, var(--primary-color) 15%, transparent);
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--spacing-md);
}

.support-icon .material-symbols-outlined {
  font-size: 28px;
  color: var(--primary-color);
}

.support-title {
  font: var(--title-medium);
  color: var(--on-surface);
  margin-bottom: var(--spacing-sm);
}

.support-description {
  font: var(--body-medium);
  color: var(--on-surface-variant);
  margin-bottom: var(--spacing-md);
}

.support-link {
  color: var(--primary-color);
  text-decoration: none;
  font: var(--label-large);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  transition: all 0.2s ease;
}

.support-link:hover {
  text-decoration: underline;
  color: color-mix(in srgb, var(--primary-color) 80%, black);
}

/* Footer */
.footer {
  background: var(--surface-variant);
  border-top: 1px solid var(--outline-variant);
  padding: var(--spacing-xl) 0 var(--spacing-lg);
  margin-top: var(--spacing-xxl);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
  gap: var(--spacing-lg);
}

.footer-branding {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.footer-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
}

.footer-title {
  font: var(--title-small);
  color: var(--on-surface);
  margin-bottom: var(--spacing-xs);
}

.footer-subtitle {
  font: var(--body-small);
  color: var(--on-surface-variant);
}

.footer-links {
  display: flex;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.footer-link {
  color: var(--on-surface-variant);
  text-decoration: none;
  font: var(--body-medium);
  transition: color 0.2s ease;
}

.footer-link:hover {
  color: var(--primary-color);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--outline-variant);
}

.footer-copyright {
  font: var(--body-small);
  color: var(--on-surface-variant);
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .hero {
    padding: var(--spacing-xl) 0;
  }
  
  .hero-icon {
    width: 100px;
    height: 100px;
  }
  
  .hero-title {
    font: var(--headline-medium);
  }
  
  .download-buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .download-btn {
    width: 100%;
    max-width: 280px;
    justify-content: center;
  }
  
  .features-grid,
  .support-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    flex-direction: column;
    text-align: center;
  }
  
  .footer-links {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .app-bar-content {
    gap: var(--spacing-sm);
  }
  
  .app-icon {
    width: 32px;
    height: 32px;
  }
  
  .app-title {
    font: var(--title-medium);
  }
  
  .hero-icon {
    width: 80px;
    height: 80px;
  }
  
  .hero-title {
    font: var(--headline-small);
  }
  
  .section-title {
    font: var(--headline-small);
  }
}

/* Smooth Scrolling */
html {
  scroll-behavior: smooth;
}

/* Focus States for Accessibility */
.download-btn:focus,
.support-link:focus,
.footer-link:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

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

.feature-card,
.support-card {
  animation: fadeInUp 0.6s ease forwards;
}

.feature-card:nth-child(2) { animation-delay: 0.1s; }
.feature-card:nth-child(3) { animation-delay: 0.2s; }
.feature-card:nth-child(4) { animation-delay: 0.3s; }

.support-card:nth-child(2) { animation-delay: 0.1s; }
.support-card:nth-child(3) { animation-delay: 0.2s; }

/* Footer */
.footer {
  background: var(--surface-container-low);
  border-top: 1px solid var(--outline-variant);
  margin-top: var(--spacing-4xl);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.footer-section h3 {
  font: var(--headline-small);
  color: var(--on-surface);
  margin-bottom: var(--spacing-md);
}

.footer-section h4 {
  font: var(--title-medium);
  color: var(--on-surface);
  margin-bottom: var(--spacing-sm);
}

.footer-section p {
  font: var(--body-medium);
  color: var(--on-surface-variant);
  line-height: 1.6;
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-links li {
  margin-bottom: var(--spacing-xs);
}

.footer-links a {
  font: var(--body-medium);
  color: var(--on-surface-variant);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

.footer-bottom {
  border-top: 1px solid var(--outline-variant);
  padding-top: var(--spacing-md);
  text-align: center;
}

.footer-bottom p {
  font: var(--body-small);
  color: var(--on-surface-variant);
  margin: 0;
}