:root {
    --bg: #FFFFFF; --ink: #111113; --surface: #FAFAFA; --line: #E8E8EA;
    --muted: #63646B; --faint: #A9AAB2; --accent: #0F62FE; --accent-ink: #FFFFFF;
    --ok: #12A150; --warn: #D97706;
    --font-sans: Pretendard, "Malgun Gothic", "Apple SD Gothic Neo", system-ui, sans-serif;
    --font-mono: ui-monospace, "Cascadia Mono", Consolas, monospace;
    --max: 1120px; --maxr: 760px;
  }
  * { margin: 0; padding: 0; box-sizing: border-box; }
  html { scroll-behavior: smooth; }
  body { background: var(--bg); color: var(--ink); font-family: var(--font-sans); line-height: 1.75; font-size: 16px; overflow-x: hidden; word-break: keep-all; overflow-wrap: break-word; }
  a { color: inherit; text-decoration: none; }
  :focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
  .wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
  .wrap-r { max-width: var(--maxr); margin: 0 auto; padding: 0 24px; }

  nav { position: sticky; top: 0; z-index: 20; background: color-mix(in srgb, var(--bg) 86%, transparent); backdrop-filter: blur(12px); border-bottom: 1px solid transparent; transition: border-color 0.3s ease; }
  nav.scrolled { border-bottom-color: var(--line); }
  .nav-in { max-width: var(--max); margin: 0 auto; padding: 0 24px; height: 64px; display: flex; align-items: center; gap: 28px; }
  .links { margin-left: auto; display: flex; gap: 26px; font-size: 14px; color: var(--muted); }
  .links a:hover { color: var(--ink); }
  .links a.here { color: var(--accent); font-weight: 700; }
  .nav-cta { font-size: 13.5px; font-weight: 700; padding: 9px 18px; border-radius: 8px; background: var(--ink); color: var(--bg); transition: background 0.2s ease; }
  .nav-cta:hover { background: var(--accent); }
  .crumb { max-width: var(--max); margin: 26px auto 0; padding: 0 24px; font-size: 12.5px; color: var(--faint); }
  .crumb a:hover { color: var(--ink); }

  .hero { padding: 46px 0 66px; }
  .eyebrow { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.18em; color: var(--accent); font-weight: 700; text-transform: uppercase; }
  h1 { font-size: clamp(38px, 5.6vw, 62px); font-weight: 800; line-height: 1.12; letter-spacing: -0.04em; margin-top: 18px; text-wrap: balance; }
  .hero .lead { margin-top: 22px; max-width: 620px; font-size: 17.5px; color: var(--muted); }
  .hero .lead strong { color: var(--ink); font-weight: 600; }
  .ctas { display: flex; gap: 12px; margin-top: 34px; flex-wrap: wrap; }
  .btn { padding: 14px 28px; border-radius: 10px; font-size: 15px; font-weight: 700; transition: transform 0.15s ease, background 0.2s ease, color 0.2s ease; display: inline-block; }
  .btn:hover { transform: translateY(-2px); }
  .btn-p { background: var(--accent); color: var(--accent-ink); }
  .btn-p:hover { background: #0B4FD1; }
  .btn-g { border: 1px solid var(--ink); color: var(--ink); }
  .btn-g:hover { background: var(--ink); color: var(--bg); }

  .kpi-strip { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--surface); }
  .kpi-in { max-width: var(--max); margin: 0 auto; padding: 26px 24px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
  .kpi { text-align: left; }
  .kpi .num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; font-size: 26px; font-weight: 700; letter-spacing: -0.02em; }
  .kpi .num em { font-style: normal; color: var(--accent); }
  .kpi .lbl { font-size: 12.5px; color: var(--muted); margin-top: 2px; }

  section { padding: 104px 0 0; }
  .sec-label { display: flex; align-items: center; gap: 14px; font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.16em; color: var(--accent); font-weight: 700; }
  .sec-label::after { content: ""; height: 1px; flex: 1; background: var(--line); }
  h2 { font-size: clamp(27px, 4vw, 40px); font-weight: 800; letter-spacing: -0.03em; margin-top: 16px; line-height: 1.25; text-wrap: balance; }
  .sec-sub { margin-top: 12px; color: var(--muted); max-width: 640px; font-size: 15.5px; }

  /* demo: document extraction */
  .demo-box { margin-top: 40px; background: var(--ink); border-radius: 20px; padding: 34px; color: #F5F6FA; display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
  .doc-stage { position: relative; background: #fff; border-radius: 12px; padding: 26px 24px; color: #333; min-height: 320px; font-size: 12.5px; }
  .doc-stage h4 { font-size: 14px; text-align: center; color: #111; letter-spacing: 0.1em; margin-bottom: 16px; }
  .form-row { display: grid; grid-template-columns: 92px 1fr; border: 1px solid #D9DADF; border-top: none; }
  .form-row:first-of-type { border-top: 1px solid #D9DADF; }
  .form-row .k { background: #F3F4F6; padding: 9px 10px; font-weight: 700; color: #555; font-size: 11.5px; }
  .form-row .v { padding: 9px 10px; font-family: var(--font-mono); position: relative; color: #1a1a1a; }
  .form-row .v.hand { font-family: Gungsuh, "Malgun Gothic", cursive; font-weight: 600; }
  .form-row .v .box { position: absolute; inset: 3px; border: 2px solid transparent; border-radius: 4px; transition: border-color 0.3s ease, background 0.3s ease; pointer-events: none; }
  .form-row.lit .v .box { border-color: var(--accent); background: rgba(15, 98, 254, 0.07); }
  .scanline { position: absolute; left: 18px; right: 18px; height: 2px; background: var(--accent); box-shadow: 0 0 14px rgba(15, 98, 254, 0.55); top: 70px; opacity: 0; }
  .json-stage { background: #16171C; border: 1px solid #26272F; border-radius: 12px; padding: 22px; font-family: var(--font-mono); font-size: 12.5px; line-height: 1.9; color: #9BA0B0; overflow: hidden; }
  .json-stage .k2 { color: #7EB1FF; }
  .json-stage .v2 { color: #C9F0DD; }
  .json-stage .flag { color: #FCD34D; }
  .json-line { opacity: 0; transform: translateY(4px); transition: opacity 0.4s ease, transform 0.4s ease; }
  .json-line.on { opacity: 1; transform: none; }
  .demo-note { grid-column: 1 / -1; font-size: 11.5px; color: #5C5F6E; }

  /* tabs / journey / acc — shared shell */
  .tabs { margin-top: 40px; }
  .tab-btns { display: flex; gap: 8px; flex-wrap: wrap; }
  .tab-btn { padding: 11px 20px; border-radius: 99px; border: 1px solid var(--line); background: var(--bg); font-size: 14px; font-weight: 600; color: var(--muted); cursor: pointer; font-family: var(--font-sans); transition: all 0.2s ease; }
  .tab-btn.on { background: var(--ink); color: var(--bg); border-color: var(--ink); }
  .tab-panel { display: none; margin-top: 26px; border: 1px solid var(--line); border-radius: 16px; padding: 34px; background: var(--surface); animation: fadeIn 0.35s ease; }
  .tab-panel.on { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 36px; align-items: center; }
  @keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
  .tab-panel h3 { font-size: 21px; font-weight: 800; letter-spacing: -0.01em; }
  .tab-panel p { margin-top: 12px; font-size: 14.5px; color: var(--muted); }
  .tab-panel ul { list-style: none; margin-top: 14px; display: flex; flex-direction: column; gap: 8px; }
  .tab-panel li { font-size: 13.5px; color: var(--muted); padding-left: 18px; position: relative; }
  .tab-panel li::before { content: "—"; position: absolute; left: 0; color: var(--accent); }
  .tab-visual { border: 1px solid var(--line); border-radius: 12px; background: #fff; padding: 22px; font-family: var(--font-mono); font-size: 12px; color: var(--muted); line-height: 2; }
  .tab-visual .hl { color: var(--accent); font-weight: 700; }

  .tracks2 { margin-top: 44px; display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
  .trk { border: 1px solid var(--line); border-radius: 16px; padding: 30px 28px; transition: border-color 0.25s ease, transform 0.25s ease; }
  .trk:hover { border-color: var(--accent); transform: translateY(-3px); }
  .trk .t-tag { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.1em; color: var(--accent); }
  .trk h4 { font-size: 19px; font-weight: 800; margin-top: 8px; }
  .trk p { font-size: 14px; color: var(--muted); margin-top: 10px; }
  .trk .flow { margin-top: 16px; font-family: var(--font-mono); font-size: 11.5px; color: var(--muted); line-height: 2; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; }
  .trk .flow .hl { color: var(--accent); font-weight: 700; }
  .trk ul { list-style: none; margin-top: 14px; display: flex; flex-direction: column; gap: 7px; }
  .trk li { font-size: 13.5px; color: var(--muted); padding-left: 18px; position: relative; }
  .trk li::before { content: "—"; position: absolute; left: 0; color: var(--accent); }

  .acc { margin-top: 40px; border-top: 1px solid var(--line); max-width: 860px; }
  .acc-item { border-bottom: 1px solid var(--line); }
  .acc-btn { width: 100%; text-align: left; padding: 22px 4px; background: none; border: none; font-family: var(--font-sans); font-size: 16.5px; font-weight: 700; color: var(--ink); cursor: pointer; display: flex; justify-content: space-between; align-items: center; }
  .acc-btn::after { content: "+"; font-size: 22px; font-weight: 400; color: var(--faint); transition: transform 0.25s ease; }
  .acc-item.open .acc-btn::after { transform: rotate(45deg); color: var(--accent); }
  .acc-body { max-height: 0; overflow: hidden; transition: max-height 0.35s ease; }
  .acc-item.open .acc-body { max-height: 900px; }
  .acc-inner { padding: 0 4px 26px; font-size: 14.5px; color: var(--muted); }
  .acc-inner .tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
  .acc-inner .tag { font-size: 12px; padding: 5px 12px; border-radius: 99px; background: var(--surface); border: 1px solid var(--line); color: var(--muted); }
  table { width: 100%; border-collapse: collapse; margin-top: 14px; font-size: 13.5px; }
  th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); }
  th { font-size: 12px; color: var(--faint); font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; }
  td { color: var(--muted); }
  td:first-child { color: var(--ink); font-weight: 600; }
  .spec-note { margin-top: 14px; font-size: 12px; color: var(--faint); }

  .principle-band { margin-top: 104px; background: var(--surface); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
  .pb-in { max-width: var(--max); margin: 0 auto; padding: 80px 24px; }
  .pb-grid { margin-top: 40px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
  .pb { background: var(--bg); border: 1px solid var(--line); border-radius: 14px; padding: 24px 22px; font-size: 13.5px; color: var(--muted); }
  .pb b { display: block; color: var(--ink); font-size: 15px; margin-bottom: 6px; }

  .cta2 { padding: 110px 0; }
  .cta2 p { margin: 14px 0 0; color: var(--muted); max-width: 560px; font-size: 15.5px; }
  .cta2 .ctas { justify-content: flex-start; }
  footer { border-top: 1px solid var(--line); background: var(--surface); padding: 40px 0 32px; }
  .f-in { max-width: var(--max); margin: 0 auto; padding: 0 24px; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 14px; }
  .f-links { display: flex; gap: 20px; font-size: 13px; color: var(--muted); }
  .f-links a:hover { color: var(--ink); }
  .f-copy { font-size: 12px; color: var(--faint); }

  .reveal { opacity: 0; transform: translateY(22px); transition: opacity 0.7s ease, transform 0.7s ease; }
  .reveal.in { opacity: 1; transform: none; }

  @media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .reveal { opacity: 1 !important; transform: none !important; transition: none !important; }
    .btn:hover, .trk:hover { transform: none; }
    .tab-panel { animation: none; }
    .json-line { opacity: 1; transform: none; transition: none; }
    .form-row.lit .v .box { transition: none; }
  }
  @media (max-width: 960px) {
    .kpi-in { grid-template-columns: repeat(2, 1fr); }
    .demo-box, .tracks2, .tab-panel.on { grid-template-columns: 1fr; }
    .pb-grid { grid-template-columns: 1fr 1fr; }
    .links { display: none; }
  }

/* ===== 공통 추가: 스킵 링크 · 모바일 내비 ===== */
.skip { position: absolute; left: -9999px; top: 0; z-index: 100; background: var(--accent); color: #fff; padding: 10px 18px; border-radius: 0 0 10px 0; font-weight: 700; font-size: 14px; }
.skip:focus { left: 0; }
.menu-btn { display: none; margin-left: auto; width: 42px; height: 42px; border: 1px solid var(--line); background: var(--bg); border-radius: 9px; cursor: pointer; padding: 0; flex-direction: column; align-items: center; justify-content: center; gap: 5px; }
.menu-btn span { display: block; width: 18px; height: 2px; background: var(--ink); border-radius: 1px; transition: transform 0.25s ease, opacity 0.25s ease; }
.menu-btn[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-btn[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.menu-btn[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
.mobile-menu { display: none; border-top: 1px solid var(--line); background: var(--bg); }
.mobile-menu.open { display: block; }
.mobile-menu a { display: block; padding: 14px 24px; font-size: 15px; color: var(--muted); border-bottom: 1px solid var(--line); }
.mobile-menu a.here { color: var(--accent); font-weight: 700; }
@media (max-width: 960px) {
  .menu-btn { display: flex; }
  nav .nav-cta { display: none; }
}
@media (min-width: 961px) { .mobile-menu { display: none !important; } }

/* ===== 인터랙티브 시뮬레이션 CTA 배너 (sound.css .real-demo-cta 동일 패턴) ===== */
.real-demo-cta { margin-top: 16px; display: flex; align-items: center; gap: 24px; justify-content: space-between; flex-wrap: wrap; padding: 26px 30px; border-radius: 16px; background: linear-gradient(120deg, #EFF5FF, #FAFAFA); border: 1px solid #C7DBFF; }
.real-demo-cta .rd-text { display: flex; flex-direction: column; gap: 5px; max-width: 560px; }
.real-demo-cta .rd-tag { font-family: var(--font-mono); font-size: 11.5px; letter-spacing: 0.08em; color: var(--accent); font-weight: 700; }
.real-demo-cta b { font-size: 16.5px; font-weight: 800; letter-spacing: -0.01em; color: var(--ink); }
.real-demo-cta span { font-size: 13.5px; color: var(--muted); line-height: 1.6; }
.real-demo-cta .btn { white-space: nowrap; flex: none; }
@media (max-width: 640px) { .real-demo-cta { padding: 22px; } .real-demo-cta .btn { width: 100%; text-align: center; } }