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

:root {
  --color-primary: #007BFF;
  --color-primary-hover: #0062CC;
  --color-primary-light: #E8F5FF;
  --color-primary-container: #C3E4FF;
  --color-secondary: #FF9800;
  --color-secondary-hover: #FB8C00;
  --color-secondary-light: #FFF3E0;
  --color-bg: #FAFAFA;
  --color-surface: #FFFFFF;
  --color-surface-variant: #F5F5F5;
  --color-border: #EEEEEE;
  --color-border-variant: #E0E0E0;
  --color-text: #212121;
  --color-text-secondary: #616161;
  --color-text-tertiary: #9E9E9E;
  --color-text-inverse: #FFFFFF;
  --color-success: #4CAF50;
  --color-overlay: rgba(0, 0, 0, 0.5);
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 20px;
  --space-2xl: 24px;
  --space-3xl: 32px;
  --space-4xl: 48px;
  --space-5xl: 64px;
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;
  --radius-full: 9999px;
  --shadow-1: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-2: 0 2px 8px rgba(0, 0, 0, 0.12);
  --shadow-3: 0 4px 12px rgba(0, 0, 0, 0.16);
  --shadow-4: 0 6px 16px rgba(0, 0, 0, 0.20);
  --shadow-5: 0 8px 24px rgba(0, 0, 0, 0.24);
  --font-primary: 'Noto Sans JP', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
  --duration-fast: 100ms;
  --duration-quick: 200ms;
  --duration-base: 300ms;
  --duration-slow: 500ms;
  --ease-standard: cubic-bezier(0.2, 0, 0, 1);
  --ease-decelerate: cubic-bezier(0, 0, 0, 1);
  --max-width: 1200px;
  --header-height: 64px;
}

[data-theme="dark"] {
  --color-primary: #2D9CFF;
  --color-primary-hover: #5AB4FF;
  --color-primary-light: #001F3F;
  --color-primary-container: #003366;
  --color-secondary: #FF9800;
  --color-secondary-hover: #FFA726;
  --color-secondary-light: #3D2800;
  --color-bg: #0A0A0A;
  --color-surface: #1A1A1A;
  --color-surface-variant: #2A2A2A;
  --color-border: #2A2A2A;
  --color-border-variant: #3A3A3A;
  --color-text: #E8E8E8;
  --color-text-secondary: #B0B0B0;
  --color-text-tertiary: #7A7A7A;
  --color-text-inverse: #0A0A0A;
  --color-overlay: rgba(0, 0, 0, 0.7);
  --shadow-1: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-2: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-3: 0 4px 12px rgba(0, 0, 0, 0.5);
  --shadow-4: 0 6px 16px rgba(0, 0, 0, 0.6);
  --shadow-5: 0 8px 24px rgba(0, 0, 0, 0.7);
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font-primary);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--duration-base) var(--ease-standard),
              color var(--duration-base) var(--ease-standard);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--duration-quick) var(--ease-standard);
}

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

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

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

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

@supports (padding: max(0px)) {
  .container {
    padding-left: max(var(--space-lg), env(safe-area-inset-left));
    padding-right: max(var(--space-lg), env(safe-area-inset-right));
  }
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  background: transparent;
  transition: background-color var(--duration-base) var(--ease-standard),
              box-shadow var(--duration-base) var(--ease-standard);
}

.header.scrolled {
  background-color: var(--color-surface);
  box-shadow: var(--shadow-2);
}

[data-theme="dark"] .header.scrolled {
  border-bottom: 1px solid var(--color-border);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: -0.01em;
  transition: color var(--duration-quick) var(--ease-standard);
}

.header-logo:hover {
  color: var(--color-primary);
}

.header-logo svg {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.header-nav a {
  color: var(--color-text-secondary);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0;
  transition: color var(--duration-quick) var(--ease-standard);
}

.header-nav a:hover {
  color: var(--color-primary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-size: 13px;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: background-color var(--duration-quick) var(--ease-standard),
              color var(--duration-quick) var(--ease-standard);
}

.lang-switch:hover {
  background-color: var(--color-surface-variant);
  color: var(--color-text);
}

.lang-switch svg {
  width: 16px;
  height: 16px;
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  transition: background-color var(--duration-quick) var(--ease-standard),
              color var(--duration-quick) var(--ease-standard);
}

.theme-toggle:hover {
  background-color: var(--color-surface-variant);
  color: var(--color-text);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

.theme-toggle .icon-moon {
  display: none;
}

[data-theme="dark"] .theme-toggle .icon-sun {
  display: none;
}

[data-theme="dark"] .theme-toggle .icon-moon {
  display: block;
}

.mobile-menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
}

.mobile-menu-toggle svg {
  width: 24px;
  height: 24px;
}

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: calc(var(--header-height) + var(--space-4xl)) var(--space-lg) var(--space-4xl);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--color-primary) 0%, transparent 70%);
  opacity: 0.04;
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -10%;
  left: -5%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, var(--color-secondary) 0%, transparent 70%);
  opacity: 0.04;
  pointer-events: none;
}

.hero-content {
  position: relative;
  text-align: center;
  max-width: 640px;
}

.hero-icon-wrapper {
  position: relative;
  display: inline-block;
  margin-bottom: var(--space-3xl);
}

.hero-icon-glow {
  position: absolute;
  inset: -20px;
  background: radial-gradient(circle, var(--color-primary) 0%, transparent 70%);
  opacity: 0.1;
  border-radius: var(--radius-full);
  filter: blur(20px);
}

.hero-icon {
  position: relative;
  width: 128px;
  height: 128px;
  color: var(--color-primary);
  filter: drop-shadow(var(--shadow-3));
}

.hero h1 {
  font-size: clamp(40px, 8vw, 64px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.hero .tagline {
  font-size: clamp(18px, 3vw, 22px);
  font-weight: 500;
  line-height: 1.4;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

.hero .description {
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-3xl);
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
}

.cta-buttons {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-2xl);
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: 0;
  transition: all var(--duration-quick) var(--ease-standard);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
}

.btn svg {
  width: 20px;
  height: 20px;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-2);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-3);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: var(--shadow-1);
}

.btn-secondary {
  background-color: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-1);
}

.btn-secondary:hover {
  background-color: var(--color-surface-variant);
  color: var(--color-text);
  box-shadow: var(--shadow-2);
  transform: translateY(-1px);
}

.btn-secondary:active {
  transform: translateY(0);
  box-shadow: none;
}

.section {
  padding: var(--space-5xl) 0;
}

.section-alt {
  background-color: var(--color-surface);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-4xl);
}

.section-header h2 {
  font-size: clamp(28px, 5vw, 36px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-md);
}

.section-header p {
  font-size: 16px;
  color: var(--color-text-secondary);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.6;
}

.section-header .accent-line {
  display: block;
  width: 48px;
  height: 3px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
  margin: var(--space-lg) auto 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

.feature-card {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  border: 1px solid var(--color-border);
  transition: all var(--duration-quick) var(--ease-standard);
}

.feature-card:hover {
  box-shadow: var(--shadow-3);
  transform: translateY(-2px);
  border-color: var(--color-primary-container);
}

[data-theme="dark"] .feature-card:hover {
  border-color: var(--color-border-variant);
}

.feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  margin-bottom: var(--space-lg);
  transition: background-color var(--duration-quick) var(--ease-standard);
}

.feature-icon svg {
  width: 24px;
  height: 24px;
}

.feature-card h3 {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: var(--space-sm);
}

.feature-card p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text-secondary);
}

.functions-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg) var(--space-3xl);
}

.function-item {
  display: flex;
  gap: var(--space-lg);
  padding: var(--space-lg);
  border-radius: var(--radius-lg);
  transition: background-color var(--duration-quick) var(--ease-standard);
}

.function-item:hover {
  background-color: var(--color-surface-variant);
}

.function-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  color: var(--color-primary);
}

.function-icon svg {
  width: 20px;
  height: 20px;
}

.function-item h3 {
  font-size: 15px;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: var(--space-xs);
}

.function-item p {
  font-size: 14px;
  line-height: 1.5;
  color: var(--color-text-secondary);
}

.screenshots {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
  padding: var(--space-3xl) 0;
}

.screenshot-mockup {
  position: relative;
  width: 220px;
  height: 440px;
  background-color: var(--color-surface-variant);
  border-radius: var(--radius-2xl);
  border: 2px solid var(--color-border);
  overflow: hidden;
  box-shadow: var(--shadow-3);
  transition: transform var(--duration-base) var(--ease-standard);
}

.screenshot-mockup:nth-child(2) {
  transform: scale(1.05);
  z-index: 1;
}

.screenshot-mockup:hover {
  transform: translateY(-8px) scale(1.02);
}

.screenshot-mockup:nth-child(2):hover {
  transform: translateY(-8px) scale(1.07);
}

.screenshot-mockup .notch {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 120px;
  height: 24px;
  background-color: var(--color-border);
  border-radius: 0 0 var(--radius-md) var(--radius-md);
}

.screenshot-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  padding: var(--space-3xl) var(--space-lg);
  color: var(--color-text-tertiary);
  font-size: 14px;
  text-align: center;
}

.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--color-border);
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--space-lg) 0;
  font-size: 16px;
  font-weight: 500;
  text-align: left;
  color: var(--color-text);
  transition: color var(--duration-quick) var(--ease-standard);
}

.faq-question:hover {
  color: var(--color-primary);
}

.faq-question svg {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  color: var(--color-text-tertiary);
  transition: transform var(--duration-base) var(--ease-standard);
}

.faq-item.open .faq-question svg {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--duration-base) var(--ease-standard),
              padding var(--duration-base) var(--ease-standard);
}

.faq-item.open .faq-answer {
  max-height: 300px;
}

.faq-answer p {
  padding-bottom: var(--space-lg);
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-text-secondary);
}

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

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: var(--space-3xl);
  margin-bottom: var(--space-3xl);
}

.footer-brand .footer-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text);
  font-weight: 700;
  font-size: 18px;
  margin-bottom: var(--space-md);
}

.footer-brand .footer-logo svg {
  width: 28px;
  height: 28px;
  color: var(--color-primary);
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text-secondary);
  max-width: 300px;
}

.footer-column h4 {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-md);
  letter-spacing: 0;
}

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

.footer-column li {
  margin-bottom: var(--space-sm);
}

.footer-column a {
  font-size: 14px;
  color: var(--color-text-secondary);
  transition: color var(--duration-quick) var(--ease-standard);
}

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-2xl);
  border-top: 1px solid var(--color-border);
  font-size: 13px;
  color: var(--color-text-tertiary);
}

.footer-bottom a {
  color: var(--color-text-tertiary);
}

.footer-bottom a:hover {
  color: var(--color-text-secondary);
}

.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--duration-slow) var(--ease-decelerate),
              transform var(--duration-slow) var(--ease-decelerate);
}

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

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

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

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }

  .header-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-lg);
    gap: 0;
    box-shadow: var(--shadow-3);
  }

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

  .header-nav a {
    padding: var(--space-md) 0;
    width: 100%;
    font-size: 16px;
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding-top: calc(var(--header-height) + var(--space-4xl));
    padding-bottom: var(--space-4xl);
  }

  .hero-icon {
    width: 96px;
    height: 96px;
  }

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

  .functions-list {
    grid-template-columns: 1fr;
  }

  .screenshots {
    flex-direction: column;
    gap: var(--space-lg);
  }

  .screenshot-mockup {
    width: 200px;
    height: 400px;
  }

  .screenshot-mockup:nth-child(2) {
    transform: none;
  }

  .screenshot-mockup:hover,
  .screenshot-mockup:nth-child(2):hover {
    transform: translateY(-4px);
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }

  .footer-bottom {
    flex-direction: column;
    gap: var(--space-sm);
    text-align: center;
  }
}

@media (max-width: 480px) {
  .cta-buttons {
    flex-direction: column;
    width: 100%;
  }

  .btn {
    width: 100%;
  }

  .hero .tagline {
    font-size: 18px;
  }
}

.legal-page {
  padding-top: calc(var(--header-height) + var(--space-4xl));
  padding-bottom: var(--space-5xl);
}

.legal-page .container {
  max-width: 720px;
}

.legal-page h1 {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-sm);
}

.legal-page .legal-updated {
  font-size: 14px;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-3xl);
}

.legal-page h2 {
  font-size: 20px;
  font-weight: 600;
  line-height: 1.3;
  margin-top: var(--space-3xl);
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.legal-page h3 {
  font-size: 16px;
  font-weight: 600;
  line-height: 1.4;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

.legal-page p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.legal-page ul,
.legal-page ol {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-text-secondary);
  padding-left: var(--space-lg);
  margin-bottom: var(--space-md);
}

.legal-page li {
  margin-bottom: var(--space-xs);
}

.legal-page a {
  color: var(--color-primary);
  text-decoration: underline;
  text-decoration-color: var(--color-primary-container);
  text-underline-offset: 2px;
  transition: text-decoration-color var(--duration-quick) var(--ease-standard);
}

.legal-page a:hover {
  text-decoration-color: var(--color-primary);
}

.legal-page strong {
  color: var(--color-text);
  font-weight: 600;
}

.legal-back {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  margin-top: var(--space-3xl);
  font-size: 15px;
  font-weight: 500;
  color: var(--color-primary);
  text-decoration: none;
}

.legal-back:hover {
  color: var(--color-primary-hover);
}

.legal-service-list {
  list-style: none;
  padding: 0;
  margin-bottom: var(--space-md);
}

.legal-service-list li {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: baseline;
  gap: var(--space-sm);
}

.legal-service-list li:last-child {
  border-bottom: none;
}

.legal-service-list .service-name {
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
}

.legal-service-list .service-desc {
  color: var(--color-text-secondary);
  font-size: 14px;
}

@media (max-width: 768px) {
  .legal-page h1 {
    font-size: 26px;
  }

  .legal-page h2 {
    font-size: 18px;
  }
}