/* Biased Models — visual system follows elayadesign landing-page-design (Part B):
   one typeface (Geist Mono, Pretendard only as the Hangul fallback), flat dark backgrounds,
   Tailwind type scale, fixed spacing tokens, base curve cubic-bezier(0.22,1,0.36,1). */
:root {
  --bg: #000000;
  --s1: #181818;
  --s2: #1f1f1f;
  --line: #272727;
  --line2: #313131;
  --fg: #ededed;
  --dim: #8a8a8a;
  --g: #39ff14;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font: "Geist Mono", "Pretendard Variable", Pretendard, ui-monospace, Menlo, monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { background: var(--bg); scroll-behavior: smooth; scroll-padding-top: 96px; }
body { color: var(--fg); font-family: var(--font); font-size: 16px; line-height: 24px; -webkit-font-smoothing: antialiased; word-break: keep-all; overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
h1, h2, h3, .tag-text { text-wrap: balance; font-weight: 600; }
p, li, dd, summary { text-wrap: pretty; }
.g { color: var(--g); }
.dim { color: var(--dim); }
:focus-visible { outline: 2px solid var(--g); outline-offset: 4px; border-radius: 4px; }

.skip { position: absolute; left: 16px; top: -64px; background: var(--g); color: #000; padding: 8px 12px; border-radius: 8px; z-index: 50; font-weight: 600; transition: transform 300ms var(--ease); }
.skip:focus { transform: translateY(80px); }

/* Nav: floating, centered, sized to content */
.nav-wrap { position: fixed; top: 16px; left: 0; right: 0; z-index: 20; display: flex; justify-content: center; pointer-events: none; padding: 0 16px; }
.nav { pointer-events: auto; display: flex; align-items: center; gap: 24px; padding: 8px 8px 8px 16px; background: rgba(24, 24, 24, 0.72); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); border: 1px solid var(--line); border-radius: 16px; font-size: 14px; line-height: 20px; }
.brand { display: flex; align-items: center; gap: 8px; font-weight: 600; white-space: nowrap; }
.mark { display: inline-block; width: 12px; height: 12px; background: var(--g); border-radius: 2px; }
.links { display: flex; gap: 16px; }
.links a, .foot-links a { color: var(--dim); transition: color 300ms var(--ease); }
.links a:hover, .links a.on, .foot-links a:hover { color: var(--fg); }
.lang { background: none; border: 0; color: var(--dim); font: inherit; cursor: pointer; display: flex; gap: 4px; padding: 4px; border-radius: 4px; }
.lang .sep { color: var(--line2); }
.lang [data-l].on { color: var(--fg); }
.btn { display: inline-flex; align-items: center; gap: 8px; background: var(--g); color: #000; font-weight: 600; font-size: 16px; line-height: 24px; padding: 8px 12px; border-radius: 8px; transition: transform 300ms var(--ease), opacity 300ms var(--ease); }
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: scale(0.98); }
.btn-sm { font-size: 14px; line-height: 20px; }
.menu-btn { display: none; width: 40px; height: 40px; background: none; border: 0; cursor: pointer; position: relative; border-radius: 8px; }
.menu-btn span { position: absolute; left: 12px; right: 12px; height: 2px; background: var(--fg); transition: transform 500ms var(--ease); }
.menu-btn span:first-child { transform: translateY(-4px); }
.menu-btn span:last-child { transform: translateY(4px); }
.menu-btn[aria-expanded="true"] span:first-child { transform: rotate(45deg); }
.menu-btn[aria-expanded="true"] span:last-child { transform: rotate(-45deg); }
.sheet { position: fixed; inset: 0; z-index: 15; background: rgba(0, 0, 0, 0.92); backdrop-filter: blur(24px); -webkit-backdrop-filter: blur(24px); display: flex; flex-direction: column; gap: 24px; padding: 96px 24px 48px; font-size: 30px; line-height: 36px; font-weight: 600; }
.sheet[hidden] { display: none; }
.sheet a { opacity: 0; transform: translateY(24px); transition: opacity 500ms var(--ease), transform 500ms var(--ease); }
.sheet.open a { opacity: 1; transform: none; }

main { max-width: 1200px; margin: 0 auto; padding: 0 40px; }

/* Hero */
.hero { min-height: 100vh; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 480px); gap: 64px; align-items: center; padding: 128px 0 80px; }
.prompt { font-size: 14px; line-height: 20px; color: var(--fg); margin-bottom: 24px; }
.cursor { display: inline-block; width: 8px; height: 1.1em; background: var(--g); vertical-align: text-bottom; margin-left: 4px; animation: blink 1.1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.grad { background: linear-gradient(90deg, #ffffff, #9b9b9b); -webkit-background-clip: text; background-clip: text; color: transparent; }
h1 { font-size: 60px; line-height: 1; letter-spacing: -0.02em; max-width: 680px; }
.sub { font-size: 18px; line-height: 28px; color: var(--dim); max-width: 680px; margin-top: 24px; }
.cta-row { margin-top: 32px; }
.quote { margin-top: 48px; padding-left: 16px; border-left: 0; position: relative; max-width: 560px; }
.quote::before { content: ""; position: absolute; left: 0; top: 2px; bottom: 2px; width: 2px; background: var(--g); }
.quote blockquote { font-size: 16px; line-height: 24px; color: var(--fg); }
.quote figcaption { font-size: 14px; line-height: 20px; color: var(--dim); margin-top: 8px; }

.term { background: var(--s1); border: 1px solid var(--line); border-radius: 16px; overflow: hidden; }
.term-bar { display: flex; align-items: center; gap: 8px; padding: 12px 16px; border-bottom: 1px solid var(--line); font-size: 12px; line-height: 16px; color: var(--dim); }
.term-bar i { width: 8px; height: 8px; border-radius: 9999px; background: var(--line2); }
.term-bar span { margin-left: 8px; }
.term-body { font-family: var(--font); font-size: 12px; line-height: 24px; padding: 16px; white-space: pre; overflow-x: auto; color: var(--fg); }
.term figcaption { font-size: 12px; line-height: 16px; color: var(--dim); padding: 0 16px 16px; }

/* Sections */
.sec { padding: 96px 0; border-top: 1px solid var(--line); }
.sec-head { display: flex; align-items: baseline; gap: 24px; margin-bottom: 48px; }
.num { font-size: 14px; line-height: 20px; color: var(--g); min-width: 32px; }
h2 { font-size: 36px; line-height: 40px; letter-spacing: -0.01em; max-width: 680px; }
h3 { font-size: 16px; line-height: 24px; margin-bottom: 8px; }
.prose { max-width: 600px; color: var(--dim); }
.prose p + p { margin-top: 16px; }
.prose p:first-child { color: var(--fg); }
.prose.wide { margin-left: 56px; max-width: 680px; }
.cols { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 64px; align-items: center; margin-left: 56px; }
.dots { background: var(--s1); border: 1px solid var(--line); border-radius: 16px; padding: 16px; }
.dots canvas { display: block; width: 100%; height: 240px; border-radius: 8px; }
.dots figcaption { font-size: 14px; line-height: 20px; margin-top: 12px; }

.grid4 { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; margin-left: 56px; }
.card { background: var(--s1); border: 1px solid var(--line); border-radius: 16px; padding: 24px; transition: transform 500ms var(--ease), border-color 300ms var(--ease); }
.card:hover { transform: translateY(-4px); border-color: var(--line2); }
.card p { font-size: 14px; line-height: 20px; color: var(--dim); }
.kicker { margin: 48px 0 0 56px; font-size: 20px; line-height: 28px; font-weight: 600; }
.kicker::before { content: "→ "; color: var(--g); }

/* Tagline reveal (B11) */
.tagline { padding: 160px 0; border-top: 1px solid var(--line); }
.tag-text { font-size: 48px; line-height: 1.1; max-width: 880px; letter-spacing: -0.01em; }
.tag-text .w { color: rgba(237, 237, 237, 0.3); transition: color 500ms var(--ease); }
.tag-text .w.on { color: var(--fg); }
.tag-text .w.on.hl { color: var(--g); }

.steps { list-style: none; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; margin-left: 56px; counter-reset: s; }
.steps li { position: relative; padding: 24px; border: 1px solid var(--line); border-radius: 16px; }
.step-n { display: block; font-size: 12px; line-height: 16px; color: var(--g); margin-bottom: 24px; }
.steps p { font-size: 14px; line-height: 20px; color: var(--dim); }

.table-wrap { margin: 64px 0 0 56px; overflow-x: auto; border: 1px solid var(--line); border-radius: 16px; }
.cmp { width: 100%; border-collapse: collapse; font-size: 14px; line-height: 20px; }
.cmp th, .cmp td { text-align: left; padding: 16px 24px; border-bottom: 1px solid var(--line); }
.cmp tbody tr:last-child th, .cmp tbody tr:last-child td { border-bottom: 0; }
.cmp thead th { color: var(--dim); font-weight: 500; background: var(--s1); }
.cmp thead th.g { color: var(--g); }
.cmp tbody th { color: var(--dim); font-weight: 400; width: 24%; }
.cmp td:last-child { color: var(--fg); }
.cmp td:nth-child(2) { color: var(--dim); }

.proof { margin-left: 56px; display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: 24px; align-items: center; padding: 24px; background: var(--s1); border: 1px solid var(--line); border-radius: 16px; transition: border-color 300ms var(--ease), transform 500ms var(--ease); }
.proof:hover { border-color: var(--g); transform: translateY(-2px); }
.proof-k { font-weight: 600; color: var(--g); white-space: nowrap; }
.proof-p { color: var(--dim); font-size: 14px; line-height: 20px; }
.proof-a { font-size: 20px; line-height: 28px; transition: transform 300ms var(--ease); }
.proof:hover .proof-a { transform: translateX(4px); }

.faq { margin-left: 56px; max-width: 760px; border: 1px solid var(--line); border-radius: 16px; overflow: hidden; }
.faq details { border-bottom: 1px solid var(--line); }
.faq details:last-child { border-bottom: 0; }
.faq summary { cursor: pointer; list-style: none; padding: 16px 24px; font-weight: 500; display: flex; justify-content: space-between; gap: 16px; transition: background-color 300ms var(--ease); }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--g); transition: transform 300ms var(--ease); }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq summary:hover { background: var(--s1); }
.faq p { padding: 0 24px 24px; color: var(--dim); font-size: 14px; line-height: 20px; }

.final { padding: 128px 0; border-top: 1px solid var(--line); text-align: center; display: flex; flex-direction: column; align-items: center; }
.final h2 { font-size: 48px; line-height: 1; }
.final .sub { margin: 24px auto 32px; }

.foot { max-width: 1200px; margin: 0 auto; padding: 32px 40px 48px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; gap: 16px; font-size: 14px; line-height: 20px; color: var(--dim); flex-wrap: wrap; }
.foot .mark { width: 8px; height: 8px; margin-right: 8px; }
.foot-links { display: flex; gap: 24px; flex-wrap: wrap; }

/* Scroll reveal */
.reveal { opacity: 0; transform: translateY(32px); transition: opacity 700ms var(--ease), transform 700ms var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* Legal / 404 */
.page { max-width: 680px; margin: 0 auto; padding: 160px 24px 96px; }
.page h1 { font-size: 36px; line-height: 40px; margin-bottom: 24px; }
.page h2 { font-size: 20px; line-height: 28px; margin: 48px 0 12px; }
.page p { color: var(--dim); margin-bottom: 16px; }
.page a:not(.btn) { color: var(--g); }

@media (max-width: 1024px) {
  .hero { grid-template-columns: 1fr; gap: 48px; min-height: auto; padding: 128px 0 80px; }
  .grid4, .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .cols { grid-template-columns: 1fr; gap: 32px; }
}
@media (max-width: 720px) {
  main { padding: 0 16px; }
  .links, .nav .btn-sm { display: none; }
  .menu-btn { display: block; }
  .nav { gap: 12px; padding: 4px 4px 4px 16px; width: 100%; justify-content: space-between; }
  .lang { margin-left: auto; }
  h1 { font-size: 36px; line-height: 40px; }
  h2 { font-size: 24px; line-height: 32px; }
  .sub { font-size: 16px; line-height: 24px; }
  .sec { padding: 64px 0; }
  .sec-head { gap: 12px; margin-bottom: 32px; }
  .prose.wide, .cols, .grid4, .steps, .table-wrap, .proof, .faq, .kicker { margin-left: 0; }
  .grid4, .steps { grid-template-columns: 1fr; }
  .tagline { padding: 96px 0; }
  .tag-text { font-size: 30px; line-height: 36px; }
  .final h2 { font-size: 36px; line-height: 40px; }
  .proof { grid-template-columns: 1fr; gap: 8px; }
  .proof-a { display: none; }
  .cmp th, .cmp td { padding: 12px 16px; }
  .foot { padding: 32px 16px 48px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { transform: none; transition: opacity 600ms linear; }
  .sheet a { transform: none; }
  .cursor { animation: none; }
  .card:hover, .btn:hover, .proof:hover { transform: none; }
}