:root {
  --color-primary: #1E40AF;
  --color-secondary: #F3F4F6;
  --color-accent: #F59E0B;
  --color-text: #111827;
  --color-white: #FFFFFF;
  --color-border: #E5E7EB;
  --color-gray-50: #F9FAFB;
  --color-gray-100: #F3F4F6;
  --color-gray-200: #E5E7EB;
  --color-gray-300: #D1D5DB;
  --color-gray-400: #9CA3AF;
  --color-gray-500: #6B7280;
  --color-gray-600: #4B5563;
  --color-gray-700: #374151;
  --color-gray-800: #1F2937;
  --color-gray-900: #111827;
  
  --font-sans: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 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);
  
  --transition: all 0.3s ease;
  --transition-fast: all 0.15s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  line-height: 1.7;
  font-size: 16px;
  font-weight: 400;
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 1rem;
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
}

h3 {
  font-size: 1.75rem;
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1rem;
}

@media (max-width: 768px) {
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
}

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

a:hover {
  opacity: 0.8;
}

p {
  margin-bottom: 1rem;
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section {
  padding: 80px 0;
}

@media (max-width: 768px) {
  .section {
    padding: 60px 0;
  }
}

.btn {
  display: inline-block;
  padding: 12px 32px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border: none;
  border-radius: 4px;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
  font-size: 16px;
}

.btn:hover {
  background-color: #1E3A8A;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover {
  background-color: var(--color-gray-300);
}

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

.btn-accent:hover {
  background-color: #DC6B02;
}

.btn-outline {
  background-color: transparent;
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
}

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

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

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

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-5 { margin-bottom: 3rem; }

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.grid {
  display: grid;
  gap: 2rem;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.card {
  background: var(--color-white);
  border-radius: 8px;
  padding: 2rem;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

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

.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;
}