:root {
  --bg: #05060b;
  --bg-2: #0b0d16;
  --card: rgba(255, 255, 255, 0.035);
  --line: rgba(255, 255, 255, 0.09);
  --text: #f4efe7;
  --muted: #a6a29d;
  --faint: #726e69;
  --red: #d63226;
  --blue: #2d62b3;
  --cream: #f8f1e6;
  --grad: linear-gradient(100deg, #f2694f 0%, #d63226 40%, #2d62b3 100%);
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --radius: 22px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; }
[id] { scroll-margin-top: 90px; }
img, svg { display: block; }

.container { width: min(1160px, 100% - 48px); margin-inline: auto; }

/* ---------- Background ---------- */
#stars {
  position: fixed; inset: 0; width: 100%; height: 100%;
  z-index: -2; pointer-events: none;
}
.nebula {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(60vw 45vw at 85% -10%, rgba(45, 98, 179, 0.22), transparent 60%),
    radial-gradient(50vw 40vw at -10% 30%, rgba(214, 50, 38, 0.14), transparent 60%),
    radial-gradient(50vw 40vw at 60% 110%, rgba(45, 98, 179, 0.14), transparent 60%);
}

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 10;
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  background: rgba(5, 6, 11, 0.6);
  border-bottom: 1px solid var(--line);
}
.nav .container { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; }
.brand-logo { height: 38px; width: auto; }
.nav-links { display: flex; gap: 28px; font-size: 14.5px; }
.nav-links a { text-decoration: none; color: var(--muted); transition: color .2s; }
.nav-links a:hover { color: var(--text); }

/* ---------- Hero ---------- */
.hero { padding: 120px 0 110px; position: relative; overflow: clip; }
.hero-grid { display: grid; grid-template-columns: 1.25fr 1fr; gap: 48px; align-items: center; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font: 500 12.5px/1 var(--mono); letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted);
  border: 1px solid var(--line); border-radius: 99px; padding: 9px 14px;
  background: var(--card);
}
.eyebrow .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--grad); box-shadow: 0 0 12px #d63226; }
h1 {
  font-size: clamp(44px, 6.4vw, 84px);
  line-height: 1.02; letter-spacing: -0.035em; font-weight: 700;
  margin: 26px 0 24px;
}
.grad-text { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lede { font-size: 20px; color: var(--muted); max-width: 34em; margin: 0 0 36px; }
.actions { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 22px; border-radius: 99px; font-weight: 600; font-size: 15.5px;
  text-decoration: none; transition: transform .2s, background .2s, border-color .2s;
}
.btn-primary { background: var(--text); color: var(--bg); }
.btn-primary:hover { transform: translateY(-1px); }
.btn-ghost { border: 1px solid var(--line); color: var(--text); background: var(--card); }
.btn-ghost:hover { border-color: rgba(255,255,255,.25); }

.hero-mark { position: relative; display: grid; place-items: center; }
.hero-mark img { width: min(380px, 80%); height: auto; filter: drop-shadow(0 30px 80px rgba(45, 98, 179, 0.4)); }
.hero-mark::before {
  content: ""; position: absolute; width: 120%; aspect-ratio: 1; border-radius: 50%;
  border: 1px dashed rgba(255,255,255,.07);
}
@media (prefers-reduced-motion: no-preference) {
  .hero-mark img { animation: float 9s ease-in-out infinite; }
  .hero-mark::before { animation: spin 120s linear infinite; }
}
@keyframes float { 50% { transform: translateY(-12px); } }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Sections ---------- */
section { padding: 100px 0; }
.section-head { max-width: 640px; margin-bottom: 48px; }
.kicker { font: 500 12.5px/1 var(--mono); letter-spacing: 0.16em; text-transform: uppercase; color: var(--faint); }
h2 { font-size: clamp(32px, 4vw, 48px); letter-spacing: -0.025em; line-height: 1.1; margin: 16px 0 14px; font-weight: 700; }
.section-head p { color: var(--muted); margin: 0; font-size: 18px; }

/* ---------- App card ---------- */
.app-card {
  position: relative; overflow: hidden;
  border: 1px solid var(--line); border-radius: 28px;
  background: linear-gradient(180deg, rgba(255,255,255,.05), rgba(255,255,255,.015));
  padding: 48px;
  display: grid; grid-template-columns: 1fr 300px; gap: 48px; align-items: center;
}
.app-card::after {
  content: ""; position: absolute; inset: -1px; border-radius: inherit; padding: 1px;
  background: linear-gradient(130deg, rgba(214,50,38,.6), transparent 35%, transparent 65%, rgba(45,98,179,.7));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude; pointer-events: none;
}
.badge {
  display: inline-block; font: 600 11.5px/1 var(--mono); letter-spacing: .14em; text-transform: uppercase;
  color: #ffd9d2; background: rgba(214, 50, 38, .14); border: 1px solid rgba(214, 50, 38, .4);
  padding: 7px 11px; border-radius: 99px;
}
.app-card h3 { font-size: 36px; letter-spacing: -0.02em; margin: 18px 0 10px; }
.app-card p { color: var(--muted); margin: 0 0 22px; }
.features { list-style: none; padding: 0; margin: 0 0 28px; display: grid; gap: 10px; }
.features li { display: flex; gap: 12px; align-items: flex-start; font-size: 15.5px; }
.features li::before {
  content: ""; flex: none; width: 18px; height: 18px; margin-top: 3px; border-radius: 50%;
  background: radial-gradient(circle at 50% 50%, #fff 0 2px, transparent 3px), var(--grad);
}
.app-card .fine { font-size: 13px; color: var(--faint); margin: 22px 0 0; }
.links-inline { display: flex; gap: 20px; font-size: 14.5px; }
.links-inline a { color: var(--muted); text-underline-offset: 4px; }
.links-inline a:hover { color: var(--text); }

/* Phone mock with notification */
.phone {
  justify-self: center; width: 260px; aspect-ratio: 9 / 19; border-radius: 44px;
  background: #0d0f18; border: 1px solid rgba(255,255,255,.12);
  box-shadow: 0 40px 80px rgba(0,0,0,.5), inset 0 0 0 7px #05060b;
  padding: 58px 14px 14px; position: relative;
}
.phone::before {
  content: ""; position: absolute; top: 17px; left: 50%; transform: translateX(-50%);
  width: 84px; height: 24px; border-radius: 20px; background: #000;
}
.phone .time { text-align: center; font-size: 54px; font-weight: 300; letter-spacing: -0.02em; line-height: 1; }
.phone .date { text-align: center; color: var(--muted); font-size: 13px; margin: 6px 0 26px; }
.notif {
  background: rgba(255,255,255,.09); backdrop-filter: blur(10px);
  border-radius: 18px; padding: 12px 13px; display: grid; grid-template-columns: 30px 1fr; gap: 10px;
  font-size: 12.5px; line-height: 1.35;
}
.notif .icon { width: 30px; height: 30px; border-radius: 8px; background: #1a1c25; display: grid; place-items: center; }
.notif .icon svg { width: 18px; height: 18px; }
.notif b { font-size: 12.5px; }
.notif .meta { display: flex; justify-content: space-between; color: var(--muted); font-size: 11px; margin-bottom: 2px; }
.notif .body { color: #d6d9e3; }
@media (prefers-reduced-motion: no-preference) {
  .notif { animation: drop 6s ease-in-out infinite; }
}
@keyframes drop {
  0%, 8% { opacity: 0; transform: translateY(-14px) scale(.98); }
  14%, 86% { opacity: 1; transform: none; }
  94%, 100% { opacity: 0; transform: translateY(-6px); }
}

/* ---------- Principles ---------- */
.about-grid { display: grid; grid-template-columns: 1fr 1.2fr; gap: 64px; align-items: start; }
.about-copy p { color: var(--muted); font-size: 18px; margin: 0 0 18px; }
.about-copy .korean { font-size: 15px; color: var(--faint); font-family: var(--mono); letter-spacing: .08em; }
.principles { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.principle {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 26px;
  background: var(--card);
}
.principle .num { font: 500 12px/1 var(--mono); color: var(--faint); letter-spacing: .1em; }
.principle h4 { margin: 14px 0 6px; font-size: 18px; letter-spacing: -0.01em; }
.principle p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.5; }

/* ---------- Contact ---------- */
.contact-card {
  border: 1px solid var(--line); border-radius: 28px; padding: 56px;
  background: radial-gradient(80% 140% at 100% 0%, rgba(45,98,179,.18), transparent 60%), var(--bg-2);
  display: grid; grid-template-columns: 1.2fr 1fr; gap: 48px; align-items: end;
}
.contact-card h2 { margin-top: 12px; }
.contact-card p { color: var(--muted); margin: 0; }
.contact-list { display: grid; gap: 22px; }
.contact-list .label { font: 500 12px/1 var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--faint); margin-bottom: 8px; }
.contact-list a { font-size: 20px; text-decoration: none; }
.contact-list a:hover { text-decoration: underline; text-underline-offset: 5px; }
address { font-style: normal; color: var(--text); line-height: 1.55; }

/* ---------- Footer ---------- */
footer { border-top: 1px solid var(--line); padding: 40px 0 56px; margin-top: 40px; }
footer .container { display: flex; justify-content: space-between; align-items: center; gap: 24px; flex-wrap: wrap; }
footer .left { display: flex; align-items: center; gap: 12px; color: var(--faint); font-size: 14px; }
footer .left img { width: 22px; height: 22px; }
footer nav { display: flex; gap: 24px; font-size: 14px; }
footer nav a { color: var(--muted); text-decoration: none; }
footer nav a:hover { color: var(--text); }

/* ---------- Document pages (privacy, terms, support) ---------- */
.doc { padding: 90px 0 40px; }
.doc .container { max-width: 780px; }
.doc h1 { font-size: clamp(38px, 5vw, 56px); margin: 18px 0 12px; }
.doc .updated { color: var(--faint); font: 500 13px/1 var(--mono); letter-spacing: .06em; }
.doc .intro { color: var(--muted); font-size: 19px; margin: 28px 0 8px; }
.doc h2 { font-size: 24px; margin: 52px 0 12px; letter-spacing: -0.015em; }
.doc h3 { font-size: 18px; margin: 28px 0 8px; }
.doc p, .doc li { color: #c8ccd8; font-size: 16.5px; }
.doc ul { padding-left: 22px; }
.doc li { margin: 6px 0; }
.doc strong { color: var(--text); }
.doc a { color: #8fb0ec; text-underline-offset: 3px; }
.doc .callout {
  border: 1px solid var(--line); border-radius: 18px; background: var(--card);
  padding: 20px 24px; margin: 28px 0;
}
.doc .callout p { margin: 0; }
.doc table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: 15px; }
.doc th, .doc td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); vertical-align: top; color: #c8ccd8; }
.doc th { color: var(--text); font-weight: 600; font-size: 13px; letter-spacing: .04em; }
.doc .toc { display: flex; flex-wrap: wrap; gap: 8px; margin: 28px 0 0; padding: 0; list-style: none; }
.toc a {
  display: inline-block; padding: 7px 12px; border-radius: 99px; border: 1px solid var(--line);
  font-size: 13.5px; color: var(--muted); text-decoration: none; background: var(--card);
}
.toc a:hover { color: var(--text); border-color: rgba(255,255,255,.22); }
details {
  border: 1px solid var(--line); border-radius: 16px; background: var(--card);
  padding: 18px 22px; margin: 12px 0;
}
summary { cursor: pointer; font-weight: 600; font-size: 17px; list-style: none; display: flex; justify-content: space-between; gap: 16px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; color: var(--muted); font-weight: 400; font-size: 22px; line-height: 1; }
details[open] summary::after { content: "–"; }
details > *:not(summary) { margin-top: 12px; }

/* ---------- 404 ---------- */
.center { text-align: center; }
.center .lede { margin-inline: auto; }
.center .actions { justify-content: center; }
.lost-mark { width: 120px; height: auto; margin: 0 auto 28px; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero { padding: 72px 0 60px; }
  .hero-grid, .about-grid, .contact-card, .app-card { grid-template-columns: 1fr; }
  .hero-mark { order: -1; }
  .hero-mark img { width: 200px; }
  .app-card, .contact-card { padding: 32px 24px; }
  .principles { grid-template-columns: 1fr; }
  .nav-links { gap: 18px; }
  section { padding: 72px 0; }
}
@media (max-width: 520px) {
  .nav-links a:not(.keep) { display: none; }
}