:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #3b82f6;
  --secondary: #3b82f6;
  --background: #ffffff;
  --surface: #f9fafb;
  --text-primary: #111827;
  --text-secondary: #6b7280;
  --border: #e5e7eb;
  --success: #10b981;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --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);
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
    sans-serif;
  background-color: var(--background);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body[lang='ja'] {
  font-family: 'Noto Sans JP', 'Inter', -apple-system, BlinkMacSystemFont,
    'Segoe UI', Roboto, sans-serif;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s;
}

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

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

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

:lang(ja) .container {
  max-width: 1000px;
}

.header {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 1rem 0;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
}

.logo img {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-md);
}

.lang-switch {
  display: flex;
  gap: 0.5rem;
}

.lang-switch button {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all 0.2s;
  font-size: 0.875rem;
  font-weight: 500;
}

.lang-switch button:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.lang-switch button.active {
  background-color: var(--primary);
  color: white;
  border-color: var(--primary);
}

.hero {
  padding: 6rem 0;
  background: linear-gradient(135deg, #eff6ff 0%, #ffffff 100%);
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.hero-text h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.hero-text h1 span {
  color: var(--primary);
}

.hero-text p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-buttons a {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 2rem;
  background-color: var(--primary);
  color: white;
  border-radius: var(--radius-lg);
  font-weight: 600;
  transition: all 0.2s;
  box-shadow: var(--shadow-md);
}

.hero-buttons a:hover {
  background-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.hero-buttons a.secondary {
  background-color: white;
  color: var(--text-primary);
  border: 2px solid var(--border);
}

.hero-buttons a.secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.hero-image {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-image img {
  max-width: 100%;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

.features {
  padding: 6rem 0;
  background: var(--background);
}

.section-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-header h2 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.section-header p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

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

.feature-card {
  background: white;
  padding: 2rem;
  border-radius: var(--radius-xl);
  border: 1px solid var(--border);
  transition: all 0.3s;
}

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

.feature-icon {
  width: 3rem;
  height: 3rem;
  background: linear-gradient(
    135deg,
    var(--primary) 0%,
    var(--primary-light) 100%
  );
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.feature-icon svg {
  width: 1.5rem;
  height: 1.5rem;
  color: white;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.feature-card p {
  color: var(--text-secondary);
  line-height: 1.6;
}

.screenshots {
  padding: 6rem 0;
  background: var(--surface);
}

.screenshots-container {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
}

.screenshot {
  max-width: 300px;
  background: white;
  border-radius: var(--radius-xl);
  padding: 1rem;
  box-shadow: var(--shadow-md);
  transition: all 0.3s;
}

.screenshot:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}

.screenshot img {
  width: 100%;
  border-radius: var(--radius-md);
}

.screenshot-caption {
  text-align: center;
  padding-top: 1rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.features-alt {
  padding: 6rem 0;
  background: var(--background);
}

.features-alt-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.feature-alt-item {
  text-align: center;
  padding: 2rem;
}

.feature-alt-item .icon {
  width: 4rem;
  height: 4rem;
  margin: 0 auto 1.5rem;
  background: var(--surface);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.feature-alt-item .icon svg {
  width: 2rem;
  height: 2rem;
  color: var(--primary);
}

.feature-alt-item h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.feature-alt-item p {
  color: var(--text-secondary);
  line-height: 1.6;
}

.faq {
  padding: 6rem 0;
  background: var(--surface);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: white;
  border-radius: var(--radius-lg);
  margin-bottom: 1rem;
  border: 1px solid var(--border);
  overflow: hidden;
}

.faq-item summary {
  padding: 1.5rem;
  cursor: pointer;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
  transition: background-color 0.2s;
}

.faq-item summary:hover {
  background-color: var(--surface);
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--text-secondary);
  transition: transform 0.2s;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item p {
  padding: 0 1.5rem 1.5rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.cta-section {
  padding: 6rem 0;
  background: linear-gradient(
    135deg,
    var(--primary) 0%,
    var(--primary-dark) 100%
  );
  text-align: center;
  color: white;
}

.cta-section h2 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.cta-section p {
  font-size: 1.125rem;
  opacity: 0.9;
  margin-bottom: 2rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.cta-section .cta-button {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 2.5rem;
  background-color: white;
  color: var(--primary);
  border-radius: var(--radius-lg);
  font-weight: 600;
  font-size: 1.125rem;
  transition: all 0.2s;
  box-shadow: var(--shadow-lg);
}

.cta-section .cta-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.footer {
  background: var(--surface);
  padding: 4rem 0 2rem;
  border-top: 1px solid var(--border);
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  margin-bottom: 3rem;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-logo img {
  width: 2rem;
  height: 2rem;
  border-radius: var(--radius-md);
}

.footer-links h4 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  color: var(--text-secondary);
  transition: color 0.2s;
}

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

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 0.875rem;
}

@media (max-width: 768px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .hero-text h1 {
    font-size: 2.5rem;
  }

  .hero-text p {
    font-size: 1.125rem;
  }

  .hero-buttons {
    justify-content: center;
  }

  .features-alt-grid {
    grid-template-columns: 1fr;
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .lang-switch button {
    padding: 0.375rem 0.75rem;
    font-size: 0.8rem;
  }
}

@media (max-width: 480px) {
  .hero-text h1 {
    font-size: 2rem;
  }

  .section-header h2 {
    font-size: 2rem;
  }
}