:root {
  color-scheme: dark;
  --bg: #0b0d10;
  --surface: #11151a;
  --surface-2: #171b21;
  --border: #2b323b;
  --text: #f6f8fb;
  --muted: #aab3bf;
  --blue: #2684ff;
  --blue-2: #67a9ff;
  --radius-control: 10px;
  --radius-panel: 18px;
  --space: clamp(20px, 3vw, 40px);
  font-family: Inter, "Segoe UI", Pretendard, system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  color: var(--text);
  background:
    radial-gradient(circle at 75% 8%, rgba(38, 132, 255, .13), transparent 24rem),
    linear-gradient(180deg, #0b0d10 0%, #0d1014 45%, #090b0e 100%);
  line-height: 1.6;
}

a { color: inherit; }

.skip-link {
  position: fixed;
  z-index: 20;
  top: 12px;
  left: 12px;
  padding: 9px 13px;
  border-radius: var(--radius-control);
  background: white;
  color: black;
  transform: translateY(-150%);
}

.skip-link:focus { transform: translateY(0); }

.site-header {
  position: sticky;
  z-index: 10;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 18px 24px;
  border-bottom: 1px solid rgba(255,255,255,.08);
  background: rgba(11,13,16,.82);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 750;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 30px;
  height: 30px;
  place-items: center;
  border-radius: 9px;
  background: linear-gradient(145deg, var(--blue-2), var(--blue));
  color: #07101d;
  font-weight: 900;
}

nav { display: flex; gap: 22px; }
nav a { color: var(--muted); font-size: 14px; text-decoration: none; }
nav a:hover, nav a:focus-visible { color: white; }

main, footer {
  width: min(1200px, calc(100% - 40px));
  margin-inline: auto;
}

.hero {
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: clamp(48px, 7vw, 96px);
  align-items: center;
  min-height: 670px;
  padding: 90px 0 70px;
}

.eyebrow {
  margin: 0 0 15px;
  color: var(--blue-2);
  font-size: 13px;
  font-weight: 750;
  letter-spacing: .12em;
  text-transform: uppercase;
}

h1, h2, h3, p { margin-top: 0; }

h1 {
  margin-bottom: 24px;
  font-size: clamp(48px, 6.1vw, 78px);
  line-height: 1.02;
  letter-spacing: -.055em;
}

h1 span { color: #8fc0ff; }

h2 {
  margin-bottom: 18px;
  font-size: clamp(34px, 4vw, 52px);
  line-height: 1.08;
  letter-spacing: -.04em;
}

h3 { margin-bottom: 10px; font-size: 20px; line-height: 1.25; }

.hero-lead, .section-heading > p, .korean p, .cta > p {
  max-width: 700px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 12px 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius-control);
  font-weight: 750;
  text-decoration: none;
  transition: transform .18s ease, border-color .18s ease, background .18s ease;
}

.button:hover { transform: translateY(-2px); }
.button:focus-visible, summary:focus-visible, a:focus-visible { outline: 3px solid rgba(103,169,255,.7); outline-offset: 3px; }
.button-primary { border-color: var(--blue); background: var(--blue); color: white; }
.button-primary:hover { background: #1677f0; }
.button-secondary { background: rgba(255,255,255,.03); }
.button-secondary:hover { border-color: #5c6877; background: rgba(255,255,255,.06); }

.download-note { margin: 14px 0 0; color: #7f8996; font-size: 13px; }

.hero-visual {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1.25fr 1fr;
  gap: 12px;
  align-items: center;
  min-height: 400px;
  padding: 36px 22px;
  border: 1px solid var(--border);
  border-radius: 28px;
  background: linear-gradient(145deg, rgba(29,35,43,.95), rgba(13,16,20,.95));
  box-shadow: 0 36px 80px rgba(0,0,0,.45), inset 0 1px rgba(255,255,255,.04);
  overflow: hidden;
}

.hero-visual::before {
  content: "";
  position: absolute;
  inset: 20% -20%;
  background: radial-gradient(circle, rgba(38,132,255,.22), transparent 55%);
  filter: blur(12px);
}

.route { position: absolute; z-index: 0; right: 12%; left: 12%; height: 2px; background: var(--blue); box-shadow: 0 0 16px var(--blue); }

.device-card, .switch-card {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 130px;
  padding: 16px 10px;
  border: 1px solid #35404d;
  border-radius: var(--radius-panel);
  background: rgba(17,21,26,.96);
  text-align: center;
}

.device-card.active { border-color: rgba(38,132,255,.72); box-shadow: 0 0 30px rgba(38,132,255,.12); }
.device-icon { margin-bottom: 8px; color: var(--blue-2); font-size: 34px; }
.switch-card span, .switch-card small { color: var(--muted); font-size: 11px; }
.switch-card strong { margin: 4px 0; font-size: 14px; }

.trust-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-block: 1px solid var(--border);
}

.trust-strip div { padding: 24px 18px; border-right: 1px solid var(--border); }
.trust-strip div:last-child { border-right: 0; }
.trust-strip strong, .trust-strip span { display: block; }
.trust-strip span { margin-top: 3px; color: var(--muted); font-size: 13px; }

.section { padding: 110px 0; }
.section-heading { max-width: 760px; margin-bottom: 46px; }

.product-shot figure { margin: 0; }
.product-shot img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-panel);
  box-shadow: 0 28px 80px rgba(0,0,0,.4);
}
.product-shot figcaption { margin-top: 12px; color: #7f8996; font-size: 13px; text-align: center; }

.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.feature-grid article {
  min-height: 245px;
  padding: 28px;
  border: 1px solid var(--border);
  border-radius: var(--radius-panel);
  background: linear-gradient(145deg, rgba(23,27,33,.94), rgba(13,16,20,.94));
}
.feature-grid p { color: var(--muted); }
.feature-number { display: block; margin-bottom: 42px; color: var(--blue-2); font-size: 12px; font-weight: 800; }

.steps { display: grid; grid-template-columns: .8fr 1.2fr; gap: 50px 90px; align-items: start; }
.steps .section-heading { grid-column: 1; margin-bottom: 0; }
.steps ol { grid-column: 2; grid-row: 1 / span 2; margin: 0; padding: 0; list-style: none; }
.steps li { display: flex; gap: 18px; padding: 22px 0; border-bottom: 1px solid var(--border); }
.steps li > span { display: grid; flex: 0 0 36px; height: 36px; place-items: center; border-radius: 50%; background: rgba(38,132,255,.13); color: var(--blue-2); font-weight: 800; }
.steps li p { margin: 3px 0 0; color: var(--muted); }
.mini-shot { grid-column: 1; width: 100%; max-width: 546px; height: auto; border: 1px solid var(--border); border-radius: 14px; }

.korean {
  display: grid;
  grid-template-columns: 1.3fr .7fr;
  gap: 60px;
  padding-inline: clamp(24px, 5vw, 64px);
  border: 1px solid rgba(38,132,255,.32);
  border-radius: 24px;
  background: linear-gradient(135deg, rgba(38,132,255,.11), rgba(17,21,26,.75));
}
.korean ul { margin: 5px 0 0; padding-left: 22px; color: #cbd3dc; }
.korean li { margin-bottom: 12px; }

.privacy { display: flex; align-items: end; justify-content: space-between; gap: 40px; }
.privacy .section-heading { margin: 0; }
.privacy > a { flex: none; color: var(--blue-2); text-decoration: none; }

.faq { max-width: 850px; margin-inline: auto; }
.faq details { border-top: 1px solid var(--border); }
.faq details:last-child { border-bottom: 1px solid var(--border); }
.faq summary { padding: 22px 4px; cursor: pointer; font-size: 18px; font-weight: 700; }
.faq details p { max-width: 700px; padding: 0 4px 22px; color: var(--muted); }

.cta {
  margin-bottom: 90px;
  padding-inline: clamp(26px, 7vw, 90px);
  border: 1px solid var(--border);
  border-radius: 26px;
  background: radial-gradient(circle at 80% 50%, rgba(38,132,255,.2), transparent 35%), var(--surface);
}
.cta > p { max-width: 650px; }

footer {
  display: flex;
  flex-wrap: wrap;
  gap: 18px 30px;
  justify-content: space-between;
  padding: 28px 0 48px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 13px;
}
footer a { color: var(--blue-2); text-decoration: none; }

@media (max-width: 900px) {
  nav a:not(:last-child) { display: none; }
  .hero { grid-template-columns: 1fr; padding-top: 70px; }
  .hero-visual { min-height: 340px; }
  .trust-strip { grid-template-columns: repeat(2, 1fr); }
  .trust-strip div:nth-child(2) { border-right: 0; }
  .trust-strip div:nth-child(-n+2) { border-bottom: 1px solid var(--border); }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: 1fr; }
  .steps .section-heading, .steps ol, .mini-shot { grid-column: 1; grid-row: auto; }
  .korean { grid-template-columns: 1fr; }
  .privacy { align-items: start; flex-direction: column; }
}

@media (max-width: 600px) {
  main, footer { width: min(100% - 28px, 1200px); }
  .site-header { padding: 14px; }
  .brand { font-size: 14px; }
  .hero { min-height: auto; padding: 60px 0; }
  h1 { font-size: clamp(43px, 14vw, 60px); }
  .hero-actions { flex-direction: column; }
  .button { width: 100%; }
  .hero-visual { grid-template-columns: 1fr 1fr; min-height: 330px; }
  .switch-card { grid-column: 1 / -1; grid-row: 1; min-height: 100px; }
  .route { display: none; }
  .trust-strip, .feature-grid { grid-template-columns: 1fr; }
  .trust-strip div, .trust-strip div:nth-child(2) { border-right: 0; border-bottom: 1px solid var(--border); }
  .section { padding: 82px 0; }
  .feature-grid article { min-height: 210px; }
  .korean { padding-inline: 22px; }
  footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}