/* ============================================================
   FACTORIAL — Improvement Proposal v1
   ============================================================ */

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

:root {
  --bg: #000;
  --bg-1: #050505;
  --bg-2: #0a0a0a;
  --bg-3: #111;
  --line: rgba(255,255,255,.08);
  --line-strong: rgba(255,255,255,.16);
  --text: #fafafa;
  --text-2: #a8a8a8;
  --text-3: #6a6a6a;
  --blue: #0066ff;
  --cyan: #00d4ff;
  --warn: #ffb800;
  --kr: 'Pretendard', system-ui, sans-serif;
  --en: 'Space Grotesk', system-ui, sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
}

html { scroll-behavior:smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--kr);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
em { font-style: italic; }
strong { font-weight: 600; }

.container { max-width: 1280px; margin: 0 auto; padding: 0 32px; }

@keyframes pulse { 0%,100%{opacity:1;transform:scale(1)} 50%{opacity:.4;transform:scale(.85)} }

/* ============================================================
   Skip link (accessibility)
   ============================================================ */
.skip-link {
  position: absolute; top: -40px; left: 0;
  background: var(--cyan); color: #000;
  padding: 8px 16px;
  z-index: 3000;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1px;
  border-radius: 0 0 4px 0;
}
.skip-link:focus { top: 0; }

/* Visible focus ring for keyboard users */
:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

/* ============================================================
   Navigation
   ============================================================ */
.nav {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(0,0,0,.7);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--line);
  transition: background .3s, border-color .3s;
}
.nav.scrolled { background: rgba(0,0,0,.92); }

.nav-inner {
  max-width: 1280px; margin: 0 auto;
  padding: 0 32px;
  height: 64px;
  display: flex; align-items: center; justify-content: space-between;
  gap: 32px;
}
.nav-brand {
  display: inline-flex; align-items: center;
  text-decoration: none;
}
.nav-name {
  font-family: var(--en);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 3px;
  color: var(--text);
}

.nav-menu { display: flex; gap: 32px; margin-left: auto; }
.nav-menu a {
  font-family: var(--en);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-2);
  letter-spacing: .5px;
  position: relative;
  transition: color .2s;
}
.nav-menu a:hover, .nav-menu a.active { color: var(--text); }
.nav-menu a.active::before {
  content:''; position: absolute; bottom: -22px; left: 0; right: 0;
  height: 1px; background: var(--cyan);
}

/* Hamburger toggle (mobile only) */
.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  width: 40px; height: 40px;
  padding: 0;
  cursor: pointer;
  position: relative;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}
.nav-toggle span {
  display: block;
  width: 18px; height: 1.5px;
  background: var(--text);
  transition: transform .25s, opacity .2s;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  padding-top: 104px;
  padding-bottom: 80px;
  display: flex; align-items: center; justify-content: center;
  overflow: hidden;
  background: var(--bg);
}

.hero-grid { position: absolute; inset: 0; pointer-events: none; }
.grid-lines {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, rgba(255,255,255,.04) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255,255,255,.04) 1px, transparent 1px);
  background-size: 80px 80px;
  mask-image: radial-gradient(ellipse at center, #000 30%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse at center, #000 30%, transparent 80%);
}
.grid-lines.vert {
  background-image:
    linear-gradient(to right, rgba(0,212,255,.08) 1px, transparent 1px);
  background-size: 240px 100%;
}
.hero-glow {
  position: absolute;
  width: 800px; height: 800px;
  left: 50%; top: 50%; transform: translate(-50%,-40%);
  background: radial-gradient(circle, rgba(0,102,255,.18) 0%, transparent 60%);
  filter: blur(40px);
}
.hero-noise {
  position: absolute; inset: 0;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='140' height='140'><filter id='n'><feTurbulence baseFrequency='0.9' numOctaves='2'/></filter><rect width='100%' height='100%' filter='url(%23n)' opacity='0.5'/></svg>");
  opacity: .06;
  mix-blend-mode: overlay;
}

.hero-tags { position: absolute; inset: 0; pointer-events: none; }
.htag {
  position: absolute;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.2px;
  color: var(--cyan);
  padding: 5px 10px;
  border: 1px solid rgba(0,212,255,.3);
  background: rgba(0,212,255,.04);
  border-radius: 2px;
  white-space: nowrap;
  animation: htagFloat 4s ease-in-out infinite;
}
.htag::before {
  content:''; position: absolute; left: -1px; top: -1px;
  width: 6px; height: 6px; background: var(--cyan);
}
.htag-warn { color: var(--warn); border-color: rgba(255,184,0,.3); background: rgba(255,184,0,.04); }
.htag-warn::before { background: var(--warn); }
.htag:nth-child(2) { animation-delay: .5s; }
.htag:nth-child(3) { animation-delay: 1s; }
.htag:nth-child(4) { animation-delay: 1.5s; }
.htag:nth-child(5) { animation-delay: 2s; }
@keyframes htagFloat {
  0%, 100% { transform: translateY(0); opacity: .8; }
  50% { transform: translateY(-6px); opacity: 1; }
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 1100px;
  padding: 0 32px;
}

.hero-meta {
  display: flex; justify-content: center; gap: 24px;
  margin-bottom: 48px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--text-3);
}
.hero-meta-item { display: inline-flex; align-items: center; gap: 8px; }
.hero-meta-item .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 8px var(--cyan);
  animation: pulse 1.6s infinite;
}

.hero-equation {
  display: flex; justify-content: center; align-items: baseline;
  gap: 6px;
  font-family: var(--en);
  font-weight: 300;
  line-height: 1;
  margin-bottom: 56px;
  position: relative;
}
.eq-zero, .eq-one {
  font-size: 200px;
  font-weight: 200;
  background: linear-gradient(180deg, #fff 0%, #888 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -8px;
}
.eq-bang {
  font-size: 200px;
  font-weight: 300;
  color: var(--cyan);
  letter-spacing: -10px;
  margin-left: -8px;
  text-shadow: 0 0 40px rgba(0,212,255,.5);
}
.eq-eq {
  font-size: 80px;
  color: var(--text-3);
  font-weight: 200;
  margin: 0 16px;
  position: relative;
  top: -28px;
}
.eq-cursor {
  display: inline-block;
  width: 6px;
  height: 100px;
  background: var(--cyan);
  margin-left: 8px;
  animation: cursorBlink 1.1s steps(2) infinite;
  align-self: flex-end;
  margin-bottom: 20px;
}
@keyframes cursorBlink { 0%,49%{opacity:1} 50%,100%{opacity:0} }

.hero-title {
  font-family: var(--kr);
  font-size: 36px;
  font-weight: 300;
  line-height: 1.4;
  margin-bottom: 24px;
  letter-spacing: -.5px;
}
.ht-line { display: block; }
.ht-line em { font-style: normal; font-weight: 600; color: var(--cyan); }

.hero-sub {
  font-size: 16px;
  color: var(--text-2);
  margin-bottom: 48px;
  line-height: 1.8;
}
.hero-sub strong { color: var(--text); font-weight: 500; }

.hero-actions { display: flex; justify-content: center; gap: 12px; margin-bottom: 80px; }

.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 14px 28px;
  border-radius: 999px;
  font-family: var(--kr);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: .3px;
  cursor: pointer;
  transition: all .25s;
  border: 1px solid transparent;
}
.btn-primary {
  background: var(--text); color: var(--bg);
}
.btn-primary:hover { background: var(--cyan); transform: translateY(-2px); box-shadow: 0 12px 32px rgba(0,212,255,.3); }
.btn-ghost {
  background: transparent; color: var(--text);
  border-color: var(--line-strong);
}
.btn-ghost:hover { border-color: var(--text); }

.hero-stats {
  display: flex; justify-content: center; align-items: center;
  gap: 32px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  max-width: 800px;
  margin: 0 auto;
}
.hs-item { text-align: center; flex: 1; }
.hs-divider { width: 1px; height: 32px; background: var(--line); }
.hs-num {
  font-family: var(--en);
  font-weight: 300;
  font-size: 36px;
  color: var(--text);
  display: flex; align-items: baseline; justify-content: center; gap: 4px;
  letter-spacing: -1px;
}
.hs-unit { font-size: 14px; color: var(--cyan); font-family: var(--mono); }
.hs-label {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--text-3);
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-top: 6px;
  white-space: nowrap;
}

/* ============================================================
   MARQUEE
   ============================================================ */
.marquee {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--bg-1);
  padding: 28px 0;
  overflow: hidden;
}
.marquee-track {
  display: flex; gap: 48px; align-items: center;
  white-space: nowrap;
  animation: marquee 40s linear infinite;
  font-family: var(--en);
  font-weight: 600;
  font-size: 36px;
  letter-spacing: -.5px;
}
.marquee-track span { color: var(--text-3); transition: color .3s; }
.marquee-track span:hover { color: var(--cyan); }
.marquee .m-dot { color: var(--cyan); font-size: 14px; }
@keyframes marquee {
  to { transform: translateX(-50%); }
}

/* ============================================================
   Section base
   ============================================================ */
.section {
  position: relative;
  padding: 140px 0;
  border-bottom: 1px solid var(--line);
}

.sec-head { margin-bottom: 80px; max-width: 900px; }
.sec-head-row { display: flex; justify-content: space-between; align-items: end; gap: 60px; max-width: none; }
.sec-tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--cyan);
  margin-bottom: 24px;
}
.sec-title {
  font-family: var(--kr);
  font-size: 56px;
  font-weight: 300;
  line-height: 1.15;
  letter-spacing: -1.5px;
  margin-bottom: 24px;
}
.sec-title em {
  font-style: normal;
  font-weight: 500;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--blue) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.sec-desc { font-size: 16px; color: var(--text-2); line-height: 1.8; max-width: 600px; }
.sec-desc-side { font-size: 14px; color: var(--text-2); line-height: 1.8; max-width: 380px; }

/* ============================================================
   BRAND — values
   ============================================================ */
.brand { background: var(--bg); }

.brand-visual {
  margin: 48px auto 64px;
  max-width: 960px;
  border: 1px solid var(--line);
  border-radius: 4px;
  overflow: hidden;
  position: relative;
  background: var(--bg-1);
}
.brand-visual img {
  width: 100%; height: auto; display: block;
  filter: brightness(.95) contrast(1.05);
}
.brand-visual::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(0,0,0,.5) 100%);
  pointer-events: none;
}

.values-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.vcard {
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 48px 40px;
  position: relative;
  transition: background .25s;
}
.vcard:hover { background: var(--bg-2); }
.vcard:hover .vcard-num { color: var(--cyan); }
.vcard-num {
  font-family: var(--en);
  font-size: 13px;
  color: var(--text-3);
  letter-spacing: 1px;
  margin-bottom: 32px;
  transition: color .25s;
}
.vcard-kr {
  font-family: var(--kr);
  font-size: 28px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
  letter-spacing: -.3px;
  line-height: 1.25;
}
.vcard-kr .kw {
  color: var(--cyan);
  font-weight: 700;
}
.vcard-en {
  font-family: var(--en);
  font-size: 13px;
  color: var(--text-3);
  margin-bottom: 32px;
  letter-spacing: 1px;
  font-weight: 400;
}
.vcard h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--cyan);
}
.vcard p {
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.75;
  margin-bottom: 32px;
}
.vcard-meta {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--text-3);
  padding-top: 16px;
  border-top: 1px dashed var(--line);
}

/* ============================================================
   TECH READY — Building diagram
   ============================================================ */
.tech { background: var(--bg-1); }

.tech-diagram {
  display: grid;
  grid-template-columns: 1fr 400px 320px;
  gap: 48px;
  margin-bottom: 100px;
  align-items: stretch;
}

.td-left { display: flex; align-items: center; }
.td-floor-list { width: 100%; display: flex; flex-direction: column; gap: 0; }
.td-floor {
  display: grid;
  grid-template-columns: 60px 1fr auto;
  gap: 16px;
  padding: 14px 0;
  border-top: 1px solid var(--line);
  align-items: center;
  cursor: pointer;
  transition: padding .25s;
}
.td-floor:last-child { border-bottom: 1px solid var(--line); }
.td-floor:hover { padding-left: 12px; }
.td-floor:hover .td-fname { color: var(--cyan); }
.td-fnum {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-3);
  letter-spacing: 1px;
}
.td-fname {
  font-family: var(--en);
  font-size: 14px;
  color: var(--text);
  font-weight: 500;
  transition: color .25s;
}
.td-flayer {
  font-family: var(--mono);
  font-size: 9px;
  color: var(--text-3);
  letter-spacing: 1px;
  text-transform: uppercase;
}
/* Preserve BI casing inside otherwise-uppercased contexts */
.bi { text-transform: none; }

.td-center {
  position: relative;
  display: flex; align-items: center; justify-content: center;
}
.td-svg {
  width: 100%; height: auto;
  max-height: 600px;
}
.td-bld rect { fill: rgba(0,212,255,.04); stroke: rgba(0,212,255,.4); stroke-width: 1; transition: fill .3s; }
.td-bld:hover rect { fill: rgba(0,212,255,.15); }

.td-robot { animation: robotMove 9s linear infinite; }
@keyframes robotMove {
  0%   { transform: translate(50px, 540px); }   /* retail floor 1F */
  20%  { transform: translate(330px, 540px); }  /* retail right */
  25%  { transform: translate(330px, 540px) rotate(0); }
  40%  { transform: translate(330px, 380px); }  /* premium 5-8F right */
  55%  { transform: translate(80px, 380px); }   /* premium left */
  75%  { transform: translate(80px, 220px); }   /* flexible 9-10F (Robot service) */
  100% { transform: translate(50px, 540px); }   /* back to retail */
}

.td-ping {
  animation: ping 2.4s infinite;
  transform-origin: center;
  transform-box: fill-box;
}
.td-ping-2 { animation-delay: .8s; }
.td-ping-3 { animation-delay: 1.6s; }
@keyframes ping {
  0% { r: 4; opacity: 1; }
  100% { r: 22; opacity: 0; }
}

.td-energy {
  stroke-dashoffset: 0;
  animation: energy 3s linear infinite;
}
@keyframes energy { to { stroke-dashoffset: -90; } }

/* Phone preview */
.td-right { display: flex; flex-direction: column; align-items: center; gap: 16px; }
.td-phone {
  width: 280px; height: 580px;
  background: linear-gradient(180deg, #1a1a1a 0%, #0a0a0a 100%);
  border-radius: 38px;
  padding: 14px;
  position: relative;
  border: 1px solid var(--line-strong);
  box-shadow:
    0 30px 80px rgba(0,102,255,.15),
    inset 0 0 0 1px rgba(255,255,255,.04);
  transform: scale(0.8);
  transform-origin: top center;
  margin-bottom: -116px; /* compensate for scale-down empty space (580*0.2) */
}
.td-phone-notch {
  position: absolute;
  top: 24px; left: 50%; transform: translateX(-50%);
  width: 90px; height: 22px;
  background: #000;
  border-radius: 12px;
  z-index: 2;
}
.td-phone-screen {
  background: linear-gradient(180deg, #001233 0%, #000814 50%, #000 100%);
  border-radius: 26px;
  width: 100%; height: 100%;
  padding: 50px 18px 18px;
  position: relative;
  overflow: hidden;
}
.taap-status {
  display: flex; justify-content: space-between; align-items: center;
  font-family: var(--mono); font-size: 11px;
  color: var(--text); margin-bottom: 24px;
}
.taap-bars { display: flex; gap: 2px; align-items: end; }
.taap-bars i {
  width: 3px; background: var(--text);
  display: inline-block;
}
.taap-bars i:nth-child(1) { height: 4px; }
.taap-bars i:nth-child(2) { height: 6px; }
.taap-bars i:nth-child(3) { height: 8px; }
.taap-bars i:nth-child(4) { height: 10px; }

.taap-greet { margin-bottom: 20px; }
.taap-hi { font-family: var(--mono); font-size: 11px; color: var(--text-3); letter-spacing: 1px; }
.taap-name { font-family: var(--en); font-size: 22px; font-weight: 600; color: var(--text); }

.taap-card {
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.06);
  border-radius: 14px;
  padding: 14px;
  margin-bottom: 10px;
}
.taap-card-primary {
  background: linear-gradient(135deg, rgba(0,102,255,.25) 0%, rgba(0,212,255,.15) 100%);
  border-color: rgba(0,212,255,.3);
}
.tcp-row { display: flex; justify-content: space-between; align-items: center; }
.tcp-label { font-family: var(--mono); font-size: 9px; color: var(--text-3); letter-spacing: 1px; }
.tcp-status { display: inline-flex; align-items: center; gap: 6px; font-family: var(--mono); font-size: 9px; color: #00ff88; letter-spacing: 1px; }
.tcp-status i { width: 6px; height: 6px; border-radius: 50%; background: #00ff88; box-shadow: 0 0 6px #00ff88; }
.tcp-status-blue { color: var(--cyan); }
.tcp-status-blue i { background: var(--cyan); box-shadow: 0 0 6px var(--cyan); }
.tcp-id { font-family: var(--en); font-size: 18px; font-weight: 600; margin: 8px 0 12px; color: var(--text); }
.tcp-meta { font-family: var(--mono); font-size: 10px; color: var(--text-3); margin-top: 8px; }
.tcp-qr {
  background: var(--text); border-radius: 8px; padding: 10px;
  margin-top: 4px;
}
.qr-grid {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 1px;
  aspect-ratio: 1;
}
.qr-grid span { background: #000; border-radius: 1px; }
.qr-grid span:nth-child(2n),
.qr-grid span:nth-child(3n),
.qr-grid span:nth-child(7n) { background: var(--text); }
.qr-grid span:nth-child(5n) { background: #000; }

.taap-row { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-bottom: 10px; }
.taap-mini {
  background: rgba(255,255,255,.03);
  border: 1px solid rgba(255,255,255,.05);
  border-radius: 10px;
  padding: 10px;
  text-align: left;
}
.tm-icon { font-size: 16px; margin-bottom: 4px; }
.tm-val { font-family: var(--en); font-size: 16px; font-weight: 600; }
.tm-lbl { font-family: var(--mono); font-size: 9px; color: var(--text-3); letter-spacing: 1px; }

.taap-progress {
  height: 4px; background: rgba(255,255,255,.06); border-radius: 2px;
  margin: 10px 0 0; overflow: hidden;
}
.taap-progress-bar {
  height: 100%; width: 65%;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
  border-radius: 2px;
  animation: taapProg 4s ease-in-out infinite;
}
@keyframes taapProg { 0% { width: 30% } 50% { width: 80% } 100% { width: 30% } }

.td-phone-label {
  display: flex; flex-direction: column; align-items: center; gap: 4px;
}
.tpl-tag { font-family: var(--mono); font-size: 10px; letter-spacing: 2px; color: var(--cyan); }
.tpl-name { font-size: 13px; color: var(--text-3); }

/* Tech stack */
.tech-stack { margin-top: 60px; }
.ts-head { display: flex; align-items: center; gap: 16px; margin-bottom: 32px; }
.ts-head-tag { font-family: var(--mono); font-size: 11px; letter-spacing: 1.5px; color: var(--text-3); }
.ts-head-line { flex: 1; height: 1px; background: var(--line); }
.ts-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.ts-cell {
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 32px 28px;
  position: relative;
  transition: background .25s;
}
.ts-cell:hover { background: var(--bg-2); }
.ts-cell-num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-3);
  letter-spacing: 1px;
  margin-bottom: 18px;
}
.ts-cell-name {
  font-family: var(--en);
  font-size: 22px;
  font-weight: 500;
  margin-bottom: 8px;
  letter-spacing: -.3px;
}
.ts-cell-desc {
  font-size: 13px; color: var(--text-2);
  line-height: 1.7; margin-bottom: 24px;
}
.ts-cell-tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--cyan);
  border: 1px solid rgba(0,212,255,.3);
  padding: 4px 10px;
  border-radius: 2px;
}

/* ============================================================
   SPACE rail
   ============================================================ */
.space { background: var(--bg); }
.space-rail {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  border-top: 1px solid var(--line);
}
.srail-card {
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 32px 24px;
  display: flex; flex-direction: column;
  transition: background .25s;
}
.srail-card:last-child { border-right: 0; }
.srail-card:hover { background: var(--bg-2); }
.srail-card:hover .srail-vis { border-color: var(--cyan); }

.srail-head {
  display: flex; align-items: baseline; gap: 12px;
  margin-bottom: 20px;
}
.srail-num { font-family: var(--mono); font-size: 11px; color: var(--text-3); letter-spacing: 1px; }
.srail-en { font-family: var(--en); font-size: 22px; font-weight: 500; letter-spacing: -.3px; }

.srail-vis {
  position: relative;
  aspect-ratio: 1.4 / 1;
  background: rgba(0,212,255,.03);
  border: 1px dashed var(--line-strong);
  margin-bottom: 24px;
  display: flex; align-items: center; justify-content: center;
  transition: border-color .25s;
  overflow: hidden;
}
.srail-vis img {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  filter: grayscale(.15) contrast(1.05) brightness(.92);
  transition: filter .35s, transform .5s;
}
.srail-card:hover .srail-vis img {
  filter: grayscale(0) contrast(1.1);
  transform: scale(1.04);
}
.srail-vis::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 50%, rgba(0,0,0,.6) 100%);
  pointer-events: none;
}
.srail-vis-label { z-index: 1; }
.srail-vis-label {
  position: absolute; bottom: 8px; left: 8px;
  font-family: var(--mono); font-size: 9px;
  color: var(--text-3); letter-spacing: 1.2px;
}

.srail-mini-grid {
  display: grid; grid-template-columns: repeat(4, 18px); gap: 6px;
}
.srail-mini-grid span {
  width: 18px; height: 18px;
  background: rgba(255,255,255,.06);
  border-radius: 2px;
}
.srail-mini-grid span.active { background: var(--cyan); box-shadow: 0 0 8px rgba(0,212,255,.5); }

.srail-shop { display: flex; flex-direction: column; gap: 4px; }
.srail-shop-row { display: flex; gap: 4px; }
.srail-shop-row span {
  width: 32px; height: 24px;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 2px;
}
.srail-shop-row span:nth-child(2) { background: rgba(0,212,255,.2); border-color: var(--cyan); }

.srail-amphi { display: flex; flex-direction: column; gap: 3px; align-items: center; }
.srail-amphi div {
  height: 8px; background: rgba(0,212,255,.2);
  border: 1px solid var(--cyan);
}
.srail-amphi div:nth-child(1) { width: 30px; }
.srail-amphi div:nth-child(2) { width: 60px; }
.srail-amphi div:nth-child(3) { width: 90px; }
.srail-amphi div:nth-child(4) { width: 120px; }

.srail-loops { position: relative; width: 100px; height: 60px; }
.srail-loops div {
  position: absolute; width: 60px; height: 60px;
  border: 1px solid var(--cyan); border-radius: 50%;
}
.srail-loops div:nth-child(1) { left: 0; }
.srail-loops div:nth-child(2) { right: 0; background: rgba(0,212,255,.1); }

.srail-card h3 {
  font-size: 16px; font-weight: 600; margin-bottom: 8px;
}
.srail-card p {
  font-size: 13px; color: var(--text-2); margin-bottom: 16px;
  line-height: 1.6;
}
.srail-card ul li {
  font-family: var(--mono); font-size: 11px;
  color: var(--text-3); padding: 4px 0;
  letter-spacing: .5px;
}
.srail-card ul li::before { content: '— '; color: var(--cyan); }

/* ============================================================
   CASE STUDY
   ============================================================ */
.case { background: var(--bg-1); }

.case-spec {
  margin-bottom: 60px;
  border: 1px solid var(--line);
}
.cs-grid {
  display: grid; grid-template-columns: repeat(4, 1fr);
}
.cs-cell {
  padding: 32px 28px;
  border-right: 1px solid var(--line);
}
.cs-cell:last-child { border-right: 0; }
.cs-key { font-family: var(--mono); font-size: 10px; letter-spacing: 1.5px; color: var(--text-3); margin-bottom: 16px; }
.cs-val {
  font-family: var(--en); font-size: 28px; font-weight: 500;
  margin-bottom: 8px; letter-spacing: -.3px;
}
.cs-unit { font-size: 14px; color: var(--cyan); margin-left: 4px; font-family: var(--mono); }
.cs-sub { font-size: 12px; color: var(--text-2); }

.case-hero {
  position: relative;
  margin-bottom: 60px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--line);
}
.case-hero-img svg,
.case-hero-img img {
  width: 100%; height: auto; display: block;
}
.case-hero-img img {
  filter: brightness(.85) contrast(1.05);
  aspect-ratio: 4 / 3;
  object-fit: cover;
}
.case-hero-overlay {
  position: absolute; inset: 0;
  display: flex; flex-direction: column; justify-content: flex-start;
  padding: 32px;
  background: linear-gradient(180deg, rgba(0,0,0,.45) 0%, transparent 35%);
  pointer-events: none;
}
.case-hero-overlay > * { pointer-events: auto; }
.cho-badge {
  display: flex; flex-direction: column; gap: 6px;
  align-self: flex-start;
}
.cho-tag {
  font-family: var(--mono); font-size: 11px;
  letter-spacing: 2px; color: var(--cyan);
  padding: 6px 12px;
  background: rgba(0,212,255,.1);
  border: 1px solid rgba(0,212,255,.3);
  display: inline-block;
}
.cho-coord { font-family: var(--mono); font-size: 10px; color: var(--text-3); letter-spacing: 1px; }

.case-cols {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--line);
  margin-bottom: 60px;
}
.case-col { padding: 40px; border-right: 1px solid var(--line); }
.case-col:last-child { border-right: 0; }
.case-col-head {
  display: flex; align-items: baseline; gap: 12px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 24px;
}
.ccl-key {
  font-family: var(--mono); font-size: 11px;
  width: 24px; height: 24px;
  border: 1px solid var(--cyan);
  display: inline-flex; align-items: center; justify-content: center;
  color: var(--cyan);
}
.case-col h3 { font-family: var(--en); font-size: 28px; font-weight: 500; flex: 1; letter-spacing: -.3px; }
.ccl-sub { font-family: var(--mono); font-size: 11px; color: var(--text-3); letter-spacing: 1px; }

.case-feats { display: flex; flex-direction: column; gap: 0; }
.case-feats li {
  display: grid; grid-template-columns: 40px 1fr;
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px dashed var(--line);
  align-items: start;
}
.case-feats li:last-child { border-bottom: 0; }
.cf-num { font-family: var(--mono); font-size: 11px; color: var(--text-3); letter-spacing: 1px; padding-top: 2px; }
.case-feats h4 { font-size: 15px; font-weight: 600; margin-bottom: 4px; color: var(--cyan); }
.case-feats p { font-size: 13px; color: var(--text-2); line-height: 1.6; }

.case-achv {
  border: 1px solid var(--line);
}
.ca-title {
  font-family: var(--en);
  font-size: 14px;
  letter-spacing: 2px;
  color: var(--text-3);
  padding: 24px 32px;
  border-bottom: 1px solid var(--line);
}
.ca-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.ca-card {
  padding: 32px 28px;
  border-right: 1px solid var(--line);
  transition: background .25s;
}
.ca-card:last-child { border-right: 0; }
.ca-card:hover { background: rgba(0,212,255,.03); }
.ca-head { display: flex; gap: 12px; align-items: center; margin-bottom: 20px; }
.ca-tag { font-family: var(--mono); font-size: 10px; color: var(--cyan); letter-spacing: 1px; }
.ca-name { font-family: var(--mono); font-size: 10px; color: var(--text-3); letter-spacing: 1.5px; }
.ca-card h4 { font-size: 18px; font-weight: 600; margin-bottom: 10px; }
.ca-card p { font-size: 13px; color: var(--text-2); line-height: 1.6; }

/* ============================================================
   CONTACT
   ============================================================ */
.contact { background: var(--bg); }
.contact-grid {
  display: grid; grid-template-columns: 1fr 1.1fr;
  gap: 80px;
  align-items: start;
}
.contact-info .sec-tag { margin-bottom: 24px; }
.contact-info .sec-title { font-size: 48px; }
.contact-desc { font-size: 16px; color: var(--text-2); margin-bottom: 48px; line-height: 1.8; }

.contact-list {
  border-top: 1px solid var(--line);
  margin-bottom: 32px;
}
.cl-item {
  display: grid;
  grid-template-columns: 80px 1fr 24px;
  gap: 16px;
  align-items: center;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
  transition: padding .25s;
}
.cl-item:hover { padding-left: 12px; }
.cl-item:hover .cl-arrow { color: var(--cyan); transform: translate(2px, -2px); }
.cl-key { font-family: var(--mono); font-size: 10px; letter-spacing: 1.5px; color: var(--text-3); }
.cl-val { font-family: var(--en); font-size: 18px; font-weight: 500; letter-spacing: .5px; }
.cl-item-static .cl-val { font-size: 14px; font-weight: 400; }
.cl-arrow { font-family: var(--mono); color: var(--text-3); transition: all .25s; }

.contact-hours {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--mono); font-size: 11px; color: var(--text-2);
  letter-spacing: 1px;
}
.ch-dot { width: 8px; height: 8px; border-radius: 50%; background: #00ff88; box-shadow: 0 0 8px #00ff88; animation: pulse 1.6s infinite; }

.contact-form {
  background: var(--bg-2);
  border: 1px solid var(--line);
  padding: 40px;
  display: flex; flex-direction: column; gap: 24px;
}
.cf-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.cf-field { display: flex; flex-direction: column; gap: 8px; border: 0; padding: 0; margin: 0; min-width: 0; }
fieldset.cf-field { border: 0; }
.cf-field label,
.cf-field legend {
  font-family: var(--mono); font-size: 10px; letter-spacing: 1.5px;
  color: var(--text-3);
  padding: 0;
  margin-bottom: 8px;
}
.cf-field input,
.cf-field textarea {
  background: transparent;
  border: 0;
  border-bottom: 1px solid var(--line-strong);
  color: var(--text);
  padding: 10px 0;
  font-family: var(--kr);
  font-size: 14px;
  resize: none;
  transition: border-color .25s;
}
.cf-field input:focus,
.cf-field textarea:focus {
  outline: 0;
  border-color: var(--cyan);
}
.cf-field input::placeholder,
.cf-field textarea::placeholder { color: var(--text-3); }

.cf-chips { display: flex; flex-wrap: wrap; gap: 8px; padding: 4px 0; }
.cf-chips input { display: none; }
.cf-chips label {
  font-family: var(--kr);
  font-size: 13px;
  padding: 8px 16px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  cursor: pointer;
  letter-spacing: 0;
  color: var(--text-2);
  transition: all .2s;
}
.cf-chips input:checked + label {
  background: var(--text); color: var(--bg);
  border-color: var(--text);
}

.cf-submit {
  display: inline-flex; justify-content: center; align-items: center;
  gap: 12px;
  background: var(--cyan); color: var(--bg);
  border: 0;
  padding: 18px 24px;
  font-family: var(--kr);
  font-size: 14px; font-weight: 600;
  letter-spacing: .5px;
  cursor: pointer;
  transition: background .2s, transform .2s;
  margin-top: 8px;
}
.cf-submit:hover { background: var(--text); transform: translateY(-2px); }
.cf-submit:disabled { opacity: .6; cursor: progress; }
.cf-arrow { font-family: var(--mono); }
/* privacy consent checkbox */
.cf-privacy {
  display: flex; align-items: flex-start; gap: 10px;
  cursor: pointer; margin-top: 8px;
}
.cf-privacy input[type="checkbox"] {
  position: absolute; opacity: 0; width: 0; height: 0;
}
.cf-check {
  flex-shrink: 0;
  width: 18px; height: 18px;
  border: 1.5px solid rgba(255,255,255,.2);
  border-radius: 4px;
  background: rgba(255,255,255,.04);
  margin-top: 1px;
  transition: border-color .15s, background .15s;
  position: relative;
}
.cf-check::after {
  content: '';
  position: absolute; top: 2px; left: 5px;
  width: 5px; height: 9px;
  border: solid #fff; border-width: 0 2px 2px 0;
  transform: rotate(45deg);
  opacity: 0; transition: opacity .15s;
}
.cf-privacy input:checked + .cf-check {
  border-color: var(--cyan); background: var(--cyan);
}
.cf-privacy input:checked + .cf-check::after { opacity: 1; }
.cf-privacy input:focus-visible + .cf-check {
  outline: 2px solid var(--cyan); outline-offset: 2px;
}
.cf-privacy-text {
  font-family: var(--kr); font-size: 13px; color: rgba(255,255,255,.7);
  line-height: 1.5;
}
.cf-privacy-text a {
  color: rgba(255,255,255,.7); text-decoration: underline;
  text-underline-offset: 2px;
}
.cf-privacy-text a:hover { color: #fff; }
.cf-required { color: var(--cyan); font-weight: 600; }
.cf-status {
  font-family: var(--kr);
  font-size: 12px;
  line-height: 1.6;
  margin: 4px 0 0;
  padding: 0;
  min-height: 1em;
  text-align: center;
}
.cf-status-ok { color: #00ff88; }
.cf-status-err { color: #ff5e7e; }

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  background: var(--bg);
  color: var(--text);
  padding: 60px 0 30px;
  border-top: 1px solid var(--line);
}
.footer-content {
  display: grid;
  grid-template-columns: 2fr 3fr;
  gap: 60px;
  margin-bottom: 40px;
}
.footer-logo {
  height: 40px; width: auto;
  margin-bottom: 15px;
  display: block;
  transition: transform .2s, filter .2s;
}
.footer-logo:hover { transform: scale(1.05); filter: brightness(1.2); }
.footer-brand p {
  color: var(--text-2);
  font-size: 14px;
}
.footer-links {
  display: flex;
  justify-content: flex-end;
}
.footer-column h4 {
  font-size: 18px;
  margin-bottom: 20px;
  font-weight: 600;
}
.social-links {
  display: flex;
  gap: 15px;
}
.social-links a {
  width: 40px; height: 40px;
  background: var(--bg-2);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  color: var(--text);
  border: 1px solid var(--line-strong);
  transition: background .2s, color .2s, transform .2s, border-color .2s;
}
.social-links a:hover {
  background: var(--cyan);
  color: var(--bg);
  border-color: var(--cyan);
  transform: translateY(-3px);
}
.social-links svg { width: 18px; height: 18px; }
.footer-bottom {
  text-align: center;
  padding-top: 30px;
  border-top: 1px solid var(--line);
}
.footer-bottom p {
  color: var(--text-3);
  font-size: 14px;
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 1100px) {
  .tech-diagram { grid-template-columns: 1fr; gap: 60px; }
  .td-right { align-self: center; }
  .case-cols { grid-template-columns: 1fr; }
  .case-col { border-right: 0; border-bottom: 1px solid var(--line); }
  .ts-grid { grid-template-columns: repeat(2, 1fr); }
  .space-rail { grid-template-columns: repeat(2, 1fr); }
  .ca-grid { grid-template-columns: repeat(2, 1fr); }
  .cs-grid { grid-template-columns: repeat(2, 1fr); }
  .cs-cell:nth-child(2) { border-right: 0; }
  .contact-grid { grid-template-columns: 1fr; gap: 60px; }
}

/* Mobile nav: hamburger toggle + slide-down menu */
@media (max-width: 860px) {
  .nav-toggle { display: flex; }
  .nav-menu {
    position: absolute;
    top: 64px; left: 0; right: 0;
    flex-direction: column;
    gap: 0;
    background: rgba(0,0,0,.96);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--line);
    padding: 8px 0;
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    transition: transform .25s, opacity .2s;
  }
  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .nav-menu li { width: 100%; }
  .nav-menu a {
    display: block;
    padding: 16px 32px;
    font-size: 14px;
    border-bottom: 1px solid var(--line);
  }
  .nav-menu li:last-child a { border-bottom: 0; }
  .nav-menu a.active::before { display: none; }
  .nav-menu a.active { color: var(--cyan); }
}

@media (max-width: 720px) {
  .nav-name { font-size: 16px; letter-spacing: 2px; }
  .eq-zero, .eq-bang, .eq-one { font-size: 120px; letter-spacing: -4px; }
  .eq-eq { font-size: 48px; top: -16px; }
  .eq-cursor { height: 60px; margin-bottom: 14px; }
  .hero-title { font-size: 24px; }
  .hero-meta { flex-wrap: wrap; gap: 12px; }
  .sec-title { font-size: 36px; }
  .sec-head-row { flex-direction: column; align-items: start; }
  .values-row { grid-template-columns: 1fr; }
  .ts-grid { grid-template-columns: 1fr; }
  .space-rail { grid-template-columns: 1fr; }
  .ca-grid { grid-template-columns: 1fr; }
  .cs-grid { grid-template-columns: 1fr; }
  .cs-cell { border-right: 0; border-bottom: 1px solid var(--line); }
  .footer-content { grid-template-columns: 1fr; gap: 32px; }
  .footer-links { justify-content: flex-start; }
  .marquee-track { font-size: 24px; }
  .cf-row { grid-template-columns: 1fr; }
}