:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Menlo, Monaco, Consolas, monospace;
  
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8F9FA;
  --bg-card: #FFFFFF;
  --bg-hover: #F1F3F5;
  
  --border-light: #E5E7EB;
  --border-card: #E5E7EB;
  
  --text-primary: #111827;
  --text-secondary: #4B5563;
  --text-tertiary: #9CA3AF;
  
  --badge-bg: #F3F4F6;
  --badge-text: #374151;
  
  --link-color: #111827;
  --link-border: #D1D5DB;
  
  --container-max: 820px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0A0A0B;
    --bg-secondary: #141416;
    --bg-card: #141416;
    --bg-hover: #1F1F23;
    
    --border-light: #27272A;
    --border-card: #27272A;
    
    --text-primary: #F4F4F5;
    --text-secondary: #A1A1AA;
    --text-tertiary: #71717A;
    
    --badge-bg: #27272A;
    --badge-text: #E4E4E7;
    
    --link-color: #F4F4F5;
    --link-border: #3F3F46;
  }
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header & Nav */
header.site-header {
  border-bottom: 1px solid var(--border-light);
  padding: 24px 0;
}

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

.brand-title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  text-decoration: none;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.15s ease;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

/* Language Switcher (Minimal Text Only) */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: 8px;
  padding-left: 14px;
  border-left: 1px solid var(--border-light);
}

.lang-btn {
  background: none;
  border: none;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-tertiary);
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
  transition: color 0.15s ease;
}

.lang-btn:hover {
  color: var(--text-primary);
}

.lang-btn.active {
  color: var(--text-primary);
  font-weight: 700;
}

.lang-divider {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  user-select: none;
}

/* Multilingual display control */
[data-lang="ko"] { display: none !important; }
html[lang="ko"] [data-lang="ko"] { display: block !important; }
html[lang="ko"] [data-lang="en"] { display: none !important; }

/* Inline elements multilingual control */
span[data-lang="ko"], a[data-lang="ko"] { display: none !important; }
html[lang="ko"] span[data-lang="ko"], html[lang="ko"] a[data-lang="ko"] { display: inline !important; }
html[lang="ko"] span[data-lang="en"], html[lang="ko"] a[data-lang="en"] { display: none !important; }

/* Inline-block elements (badges, buttons) */
.platform-badge[data-lang="ko"] { display: none !important; }
html[lang="ko"] .platform-badge[data-lang="ko"] { display: inline-block !important; }
html[lang="ko"] .platform-badge[data-lang="en"] { display: none !important; }


/* Main Content Area */
main.site-content {
  flex: 1;
  padding: 48px 0 64px 0;
}

.intro-section {
  margin-bottom: 48px;
}

.intro-heading {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 12px;
}

.intro-desc {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  max-width: 640px;
}

/* App List */
.app-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.app-card {
  display: flex;
  align-items: flex-start;
  gap: 24px;
  padding: 24px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: 16px;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.app-card:hover {
  border-color: var(--link-border);
  background-color: var(--bg-hover);
}

.app-icon {
  width: 76px;
  height: 76px;
  border-radius: 17px;
  flex-shrink: 0;
  object-fit: cover;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.app-body {
  flex: 1;
  min-width: 0;
}

.app-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
  flex-wrap: wrap;
}

.app-title {
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.platform-badge {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 3px 8px;
  border-radius: 6px;
  background-color: var(--badge-bg);
  color: var(--badge-text);
}

.app-description {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.55;
  margin-bottom: 16px;
}

.app-links {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.app-link {
  font-size: 0.875rem;
  color: var(--link-color);
  text-decoration: none;
  padding-bottom: 1px;
  border-bottom: 1px solid var(--link-border);
  transition: border-color 0.15s ease, opacity 0.15s ease;
}

.app-link:hover {
  border-color: var(--text-primary);
}

.app-link.muted {
  color: var(--text-tertiary);
  border-bottom-color: transparent;
  cursor: default;
}

/* Article / Policy / Support Styles */
.doc-article {
  max-width: 680px;
}

.doc-header {
  margin-bottom: 36px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-light);
}

.doc-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 8px;
}

.doc-meta {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.doc-content h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 36px;
  margin-bottom: 12px;
  letter-spacing: -0.015em;
}

.doc-content p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.doc-content ul {
  margin-bottom: 20px;
  padding-left: 20px;
}

.doc-content li {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.doc-content strong {
  color: var(--text-primary);
  font-weight: 600;
}

.contact-card {
  margin-top: 36px;
  padding: 24px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: 12px;
}

.contact-card h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.contact-card p {
  margin-bottom: 8px;
}

.contact-card a {
  color: var(--text-primary);
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* Footer */
footer.site-footer {
  border-top: 1px solid var(--border-light);
  padding: 32px 0;
  margin-top: auto;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-copy {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer-link {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  text-decoration: none;
}

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

/* Responsive */
@media (max-width: 600px) {
  .app-card {
    flex-direction: column;
    gap: 16px;
    padding: 20px;
  }
  
  .app-icon {
    width: 64px;
    height: 64px;
    border-radius: 14px;
  }
  
  .intro-heading {
    font-size: 1.625rem;
  }
  
  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}