/* ============================================================
   VTS Library — shared design system
   Tokens copied verbatim from DESIGN.md. No colors, fonts,
   spacing, or radii introduced beyond what is defined there.
   ============================================================ */
:root {
  /* colors */
  --primary: #5e6ad2;
  --on-primary: #ffffff;
  --primary-hover: #828fff;
  --primary-focus: #5e69d1;
  --ink: #f7f8f8;
  --ink-muted: #d0d6e0;
  --ink-subtle: #8a8f98;
  --ink-tertiary: #62666d;
  --canvas: #010102;
  --surface-1: #0f1011;
  --surface-2: #141516;
  --surface-3: #18191a;
  --surface-4: #191a1b;
  --hairline: #23252a;
  --hairline-strong: #34343a;
  --hairline-tertiary: #3e3e44;
  --inverse-canvas: #ffffff;
  --inverse-ink: #000000;
  --semantic-success: #27a644;

  --font-display: 'Inter', 'SF Pro Display', -apple-system, system-ui, 'Segoe UI', Roboto, sans-serif;
  --font-text: 'Inter', 'SF Pro Display', -apple-system, system-ui, 'Segoe UI', Roboto, sans-serif;

  --sp-xxs: 4px;
  --sp-xs: 8px;
  --sp-sm: 12px;
  --sp-md: 16px;
  --sp-lg: 24px;
  --sp-xl: 32px;
  --sp-xxl: 48px;
  --sp-section: 96px;

  --r-xs: 4px;
  --r-sm: 6px;
  --r-md: 8px;
  --r-lg: 12px;
  --r-xl: 16px;
  --r-xxl: 24px;
  --r-pill: 9999px;

  --focus-ring: rgba(94, 105, 209, 0.5);
}

:focus-visible { outline: 2px solid var(--focus-ring); outline-offset: 2px; }

.skip-link {
  position: absolute;
  top: var(--sp-md);
  left: var(--sp-md);
  background: var(--surface-2);
  color: var(--ink);
  padding: var(--sp-sm) var(--sp-md);
  border-radius: var(--r-md);
  font-family: var(--font-text);
  font-size: 14px;
  z-index: 100;
  transform: translateY(-150%);
  transition: transform 0.15s;
}
.skip-link:focus-visible { transform: translateY(0); }
@media (prefers-reduced-motion: reduce) { .skip-link { transition: none; } }

* { box-sizing: border-box; }
html { color-scheme: dark; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--canvas);
  color: var(--ink);
  font-family: var(--font-text);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.50;
  letter-spacing: -0.05px;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
.container { max-width: 1280px; margin: 0 auto; padding: 0 var(--sp-xl); }

/* ---------- typography ---------- */
.eyebrow {
  font-family: var(--font-text);
  font-size: 13px; font-weight: 500; line-height: 1.30; letter-spacing: 0.4px;
  color: var(--primary-hover); text-transform: uppercase;
}
.display-xl {
  font-family: var(--font-display); font-size: 80px; font-weight: 600;
  line-height: 1.05; letter-spacing: -3.0px; color: var(--ink); margin: 0; text-wrap: balance;
}
.display-lg {
  font-family: var(--font-display); font-size: 56px; font-weight: 600;
  line-height: 1.10; letter-spacing: -1.8px; color: var(--ink); margin: 0; text-wrap: balance;
}
.display-md {
  font-family: var(--font-display); font-size: 40px; font-weight: 600;
  line-height: 1.15; letter-spacing: -1.0px; color: var(--ink); margin: 0; text-wrap: balance;
}
.headline {
  font-family: var(--font-display); font-size: 28px; font-weight: 600;
  line-height: 1.20; letter-spacing: -0.6px; color: var(--ink); margin: 0; text-wrap: balance;
}
.card-title {
  font-family: var(--font-display); font-size: 22px; font-weight: 500;
  line-height: 1.25; letter-spacing: -0.4px; color: var(--ink); margin: 0; text-wrap: balance;
}
.subhead {
  font-family: var(--font-display); font-size: 20px; font-weight: 400;
  line-height: 1.40; letter-spacing: -0.2px; color: var(--ink); margin: 0;
}
.body-lg {
  font-family: var(--font-text); font-size: 18px; font-weight: 400;
  line-height: 1.50; letter-spacing: -0.1px; color: var(--ink-muted);
}
.body { font-family: var(--font-text); font-size: 16px; font-weight: 400; line-height: 1.50; letter-spacing: -0.05px; color: var(--ink-subtle); }
.body-sm { font-family: var(--font-text); font-size: 14px; font-weight: 400; line-height: 1.50; letter-spacing: 0; }
.caption { font-family: var(--font-text); font-size: 12px; font-weight: 400; line-height: 1.40; letter-spacing: 0; color: var(--ink-subtle); }

/* ---------- top-nav ---------- */
.top-nav {
  background: var(--canvas); color: var(--ink); height: 56px;
  display: flex; align-items: center; position: sticky; top: 0; z-index: 10;
  border-bottom: 1px solid var(--hairline);
}
.top-nav .container { display: flex; align-items: center; justify-content: space-between; width: 100%; }
.wordmark { font-family: var(--font-display); font-weight: 600; font-size: 16px; letter-spacing: -0.2px; color: var(--ink); display: flex; align-items: center; gap: var(--sp-xs); }
.wordmark .wordmark-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: var(--r-sm); background: var(--primary);
  color: var(--on-primary); font-size: 11px; font-weight: 700;
}
.nav-links { display: flex; gap: var(--sp-xl); font-family: var(--font-text); font-size: 14px; font-weight: 400; letter-spacing: 0; color: var(--ink-subtle); }
.nav-links a:hover, .nav-links a.active { color: var(--ink); }
.nav-actions { display: flex; gap: var(--sp-xs); }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  font-family: var(--font-text); font-size: 14px; font-weight: 500; line-height: 1.20; letter-spacing: 0;
  border-radius: var(--r-md); padding: 8px 14px; border: none; cursor: pointer; white-space: nowrap;
}
.btn-primary { background: var(--primary); color: var(--on-primary); }
.btn-primary:hover { background: var(--primary-hover); }
.btn-primary:active { background: var(--primary-focus); }
.btn-secondary { background: var(--surface-1); color: var(--ink); border: 1px solid var(--hairline); }
.btn-secondary:hover { background: var(--surface-2); }
.btn-tertiary { background: transparent; color: var(--ink); }
.btn-tertiary:hover { color: var(--primary-hover); }
.btn-block { width: 100%; }
.btn[disabled] { opacity: 0.5; cursor: not-allowed; }

/* ---------- badges ---------- */
.status-badge {
  display: inline-flex; align-items: center; gap: 4px;
  background: var(--surface-2); color: var(--ink-muted);
  font-family: var(--font-text); font-size: 12px; line-height: 1.40;
  border-radius: var(--r-pill); padding: 2px 8px; white-space: nowrap;
}
.badge-public { background: rgba(39, 166, 68, 0.14); color: #6bd987; }
.badge-member { background: rgba(94, 106, 210, 0.16); color: var(--primary-hover); }
.badge-draft { background: var(--surface-2); color: var(--ink-tertiary); }

/* ---------- filter chips (pricing-tab component) ---------- */
.filter-row { display: flex; gap: var(--sp-xs); flex-wrap: wrap; }
.filter-chip {
  background: var(--canvas); color: var(--ink-subtle);
  font-family: var(--font-text); font-size: 14px; font-weight: 500;
  border-radius: var(--r-pill); padding: 6px 14px; border: 1px solid var(--hairline);
  cursor: pointer;
}
.filter-chip.selected { background: var(--surface-2); color: var(--ink); border-color: var(--hairline-strong); }

/* ---------- section rhythm ---------- */
section { padding: var(--sp-section) 0; }
section.tight-top { padding-top: var(--sp-xxl); }
section.tight-bottom { padding-bottom: var(--sp-xxl); }
section[id], footer[id] { scroll-margin-top: 56px; }
.section-head { max-width: 640px; margin-bottom: var(--sp-xxl); }
.section-head-row { display: flex; align-items: flex-end; justify-content: space-between; gap: var(--sp-lg); margin-bottom: var(--sp-xxl); flex-wrap: wrap; }
.section-head .eyebrow { margin-bottom: var(--sp-sm); }
.section-head .display-lg { margin-bottom: var(--sp-md); }
.section-head .display-md { margin-bottom: var(--sp-md); }

/* ---------- grids ---------- */
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-lg); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--sp-lg); }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--sp-lg); }

/* ---------- feature-card ---------- */
.feature-card { background: var(--surface-1); color: var(--ink); border-radius: var(--r-lg); padding: var(--sp-lg); border: 1px solid var(--hairline); }
.feature-card .card-title { margin-bottom: var(--sp-sm); }
.feature-card .body { margin: 0; }
.feature-card .caption { display: block; margin-bottom: var(--sp-md); color: var(--ink-tertiary); }

/* ---------- resource card ---------- */
.resource-card {
  background: var(--surface-1); border-radius: var(--r-lg); border: 1px solid var(--hairline);
  padding: var(--sp-lg); display: flex; flex-direction: column; gap: var(--sp-sm);
  transition: border-color .15s;
}
.resource-card:hover { border-color: var(--hairline-strong); }
.resource-card-top { display: flex; align-items: flex-start; justify-content: space-between; gap: var(--sp-sm); }
.resource-card-icon {
  width: 40px; height: 40px; border-radius: var(--r-md); background: var(--surface-2);
  display: flex; align-items: center; justify-content: center; color: var(--primary-hover);
  font-family: var(--font-display); font-weight: 600; font-size: 15px; flex-shrink: 0;
}
.resource-card .card-title { margin: var(--sp-xs) 0 0; }
.resource-card .body-sm.desc { color: var(--ink-subtle); margin: 0; flex: 1; }
.resource-card-meta { display: flex; align-items: center; justify-content: space-between; padding-top: var(--sp-sm); border-top: 1px solid var(--hairline); margin-top: var(--sp-xs); }
.resource-card-meta .caption { color: var(--ink-tertiary); }
.resource-card-link { font-family: var(--font-text); font-size: 14px; font-weight: 500; color: var(--primary-hover); }
.resource-card-link:hover { color: var(--primary); }

/* ---------- category tile ---------- */
.category-tile { background: var(--surface-1); border-radius: var(--r-lg); border: 1px solid var(--hairline); padding: var(--sp-lg); display: flex; flex-direction: column; gap: var(--sp-xs); }
.category-tile:hover { border-color: var(--hairline-strong); background: var(--surface-2); }
.category-tile .category-count { color: var(--ink-tertiary); }

/* ---------- cta-banner ---------- */
.cta-banner {
  background: var(--surface-1); color: var(--ink); border-radius: var(--r-lg); padding: var(--sp-xxl);
  border: 1px solid var(--hairline); display: flex; align-items: center; justify-content: space-between;
  gap: var(--sp-xl); flex-wrap: wrap;
}
.cta-banner .headline { margin-bottom: var(--sp-xs); }
.cta-banner .body { margin: 0; }
.cta-banner-actions { display: flex; gap: var(--sp-sm); }

/* ---------- footer ---------- */
.footer { background: var(--canvas); color: var(--ink-subtle); padding: 64px 32px; border-top: 1px solid var(--hairline); }
.footer-inner { max-width: 1280px; margin: 0 auto; display: flex; justify-content: space-between; flex-wrap: wrap; gap: var(--sp-xxl); }
.footer-cols { display: flex; gap: var(--sp-xxl); flex-wrap: wrap; }
.footer-col { display: flex; flex-direction: column; gap: var(--sp-sm); }
.footer-col-title { font-family: var(--font-text); font-size: 14px; font-weight: 500; color: var(--ink-muted); margin-bottom: var(--sp-xxs); }
.footer-col a.caption:hover { color: var(--ink); }
.footer-bottom { max-width: 1280px; margin: var(--sp-xxl) auto 0; padding-top: var(--sp-lg); border-top: 1px solid var(--hairline); }

/* ---------- avatar / profile ---------- */
.avatar-photo {
  border-radius: var(--r-full, 9999px);
  background: var(--surface-2);
  border: 1px solid var(--hairline-strong);
  display: flex; align-items: center; justify-content: center;
  color: var(--ink-tertiary); font-family: var(--font-text); text-align: center;
  flex-shrink: 0;
}
.intro-band { display: flex; align-items: center; gap: var(--sp-xl); flex-wrap: wrap; }
.intro-band .avatar-photo { width: 96px; height: 96px; font-size: 12px; }
.intro-band-text { flex: 1; min-width: 260px; }
.placeholder-text { color: var(--ink-tertiary); font-style: italic; }

/* ---------- external link card ---------- */
.link-row {
  display: flex; align-items: center; justify-content: space-between; gap: var(--sp-md);
  background: var(--surface-1); border: 1px solid var(--hairline); border-radius: var(--r-md);
  padding: var(--sp-md) var(--sp-lg);
}
.link-row:hover { border-color: var(--hairline-strong); }
.link-row-text { display: flex; flex-direction: column; gap: 2px; }
.link-row-title { font-family: var(--font-text); font-size: 15px; font-weight: 500; color: var(--ink); }
.link-row-arrow { color: var(--ink-tertiary); flex-shrink: 0; }
.link-row:hover .link-row-arrow { color: var(--primary-hover); }

/* ---------- timeline (활동/이력) ---------- */
.timeline { display: flex; flex-direction: column; }
.timeline-item { display: flex; gap: var(--sp-lg); position: relative; padding-bottom: var(--sp-xl); }
.timeline-item:last-child { padding-bottom: 0; }
.timeline-rail { display: flex; flex-direction: column; align-items: center; width: 12px; flex-shrink: 0; }
.timeline-dot { width: 10px; height: 10px; border-radius: var(--r-pill); background: var(--primary); margin-top: 6px; flex-shrink: 0; }
.timeline-line { flex: 1; width: 1px; background: var(--hairline); margin-top: 4px; }
.timeline-item:last-child .timeline-line { display: none; }
.timeline-year { font-family: var(--font-text); font-size: 13px; font-weight: 600; color: var(--primary-hover); margin-bottom: 2px; }
.timeline-content { flex: 1; }
.timeline-title { font-family: var(--font-text); font-size: 16px; font-weight: 500; color: var(--ink); margin: 0 0 2px; }
.timeline-desc { margin: 0; }

/* ---------- activity log row ---------- */
.activity-row { display: flex; gap: var(--sp-md); padding: var(--sp-md) 0; border-bottom: 1px solid var(--hairline); }
.activity-row:last-child { border-bottom: none; }
.activity-date { width: 90px; flex-shrink: 0; color: var(--ink-tertiary); }
.activity-body { flex: 1; }
.activity-title { font-family: var(--font-text); font-size: 15px; font-weight: 500; color: var(--ink); margin: 0 0 2px; }

/* ---------- trend / feed card ---------- */
.trend-card { background: var(--surface-1); border: 1px solid var(--hairline); border-radius: var(--r-lg); padding: var(--sp-lg); display: flex; flex-direction: column; gap: var(--sp-sm); }
.trend-card-top { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-sm); }
.trend-tag { background: var(--surface-2); color: var(--ink-muted); }
.trend-date { color: var(--ink-tertiary); }
.trend-card .card-title { margin: 0; }

/* ---------- forms ---------- */
.auth-shell { min-height: calc(100vh - 56px); display: flex; align-items: center; justify-content: center; padding: var(--sp-xxl) var(--sp-md); }
.auth-card { width: 100%; max-width: 400px; background: var(--surface-1); border: 1px solid var(--hairline); border-radius: var(--r-lg); padding: var(--sp-xxl); }
.auth-card .headline { margin-bottom: var(--sp-xs); text-align: center; }
.auth-card .body { margin: 0 0 var(--sp-xl); text-align: center; }
.field { display: flex; flex-direction: column; gap: var(--sp-xxs); margin-bottom: var(--sp-md); }
.field label { font-family: var(--font-text); font-size: 13px; font-weight: 500; color: var(--ink-muted); }
.text-input {
  background: var(--surface-1); color: var(--ink); font-family: var(--font-text); font-size: 16px;
  border-radius: var(--r-md); padding: 10px 12px; border: 1px solid var(--hairline-strong); width: 100%;
}
.text-input:focus { outline: 2px solid var(--focus-ring); outline-offset: 1px; border-color: var(--primary-focus); }
.text-input::placeholder { color: var(--ink-tertiary); }
.field-hint { color: var(--ink-tertiary); }
.password-field { position: relative; }
.password-field .text-input { padding-right: 40px; }
.password-toggle {
  position: absolute; right: 4px; top: 50%; transform: translateY(-50%);
  background: none; border: none; cursor: pointer; padding: 8px;
  color: var(--ink-tertiary); display: flex; align-items: center; justify-content: center;
}
.password-toggle:hover { color: var(--ink-muted); }
.auth-divider { display: flex; align-items: center; gap: var(--sp-sm); margin: var(--sp-lg) 0; color: var(--ink-tertiary); }
.auth-divider::before, .auth-divider::after { content: ''; flex: 1; height: 1px; background: var(--hairline); }
.auth-switch { text-align: center; margin-top: var(--sp-lg); }
.auth-switch a { color: var(--primary-hover); font-weight: 500; }
.auth-switch a:hover { color: var(--primary); }
.checkbox-row { display: flex; align-items: flex-start; gap: var(--sp-xs); margin-bottom: var(--sp-lg); }
.checkbox-row input { margin-top: 3px; accent-color: var(--primary); }
.checkbox-row label { color: var(--ink-subtle); font-size: 13px; line-height: 1.5; }

/* ---------- document list (IALA library) ---------- */
.doc-list { display: flex; flex-direction: column; gap: var(--sp-sm); }
.doc-list-row {
  background: var(--surface-1); border: 1px solid var(--hairline); border-radius: var(--r-md);
  padding: var(--sp-md) var(--sp-lg);
}
.doc-list-row:hover { border-color: var(--hairline-strong); }
.doc-list-topline { display: flex; align-items: baseline; gap: var(--sp-xs); flex-wrap: wrap; margin-bottom: 4px; }
.doc-type-badge {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 20px; padding: 1px 5px; border-radius: var(--r-xs);
  background: var(--surface-2); color: var(--ink-tertiary);
  font-family: var(--font-text); font-size: 10px; font-weight: 600; letter-spacing: 0.2px;
}
.doc-code { font-family: var(--font-display); font-weight: 600; font-size: 14px; color: var(--ink-muted); }
.doc-ed { font-family: var(--font-text); font-size: 12px; color: var(--ink-tertiary); }
.doc-title-link {
  display: block; font-family: var(--font-text); font-size: 16px; font-weight: 500;
  color: var(--primary-hover); margin: 0 0 4px;
}
.doc-title-link:hover { color: var(--primary); text-decoration: underline; }
.doc-list-desc { margin: 0; color: var(--ink-subtle); }
.doc-translation-badge { display: inline-flex; margin-top: var(--sp-sm); }
.lib-jump { display: flex; gap: var(--sp-sm); flex-wrap: wrap; margin-bottom: var(--sp-xxl); }

/* ---------- responsive ---------- */
@media (max-width: 1024px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .top-nav { height: auto; }
  .top-nav .container { flex-wrap: wrap; padding-top: var(--sp-sm); padding-bottom: var(--sp-sm); row-gap: var(--sp-sm); }
  .nav-links { order: 3; width: 100%; justify-content: center; gap: var(--sp-lg); }
  .display-xl { font-size: 48px; letter-spacing: -1.8px; }
  .display-lg { font-size: 36px; letter-spacing: -1.2px; }
  .cta-banner { flex-direction: column; align-items: flex-start; }
  .section-head-row { flex-direction: column; align-items: flex-start; }
}
@media (max-width: 480px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .display-xl { font-size: 36px; letter-spacing: -1.0px; }
  .container { padding: 0 var(--sp-md); }
  section { padding: var(--sp-xxl) 0; }
}