:root {
  --accent: #19d7f2;
  --accent-dim: #0bb8d4;
  --accent-warm: #ff7a3d;
  --bg: #070b1a;
  --bg-glow: #0d1a3a;
  --text: #f4f7ff;
  --text-sub: #9aa8c7;
  --card: #10182c;
  --border: rgba(25, 215, 242, 0.2);
  --font-display: "Pretendard", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
}

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

body {
  font-family: var(--font-display);
  background:
    radial-gradient(900px 480px at 12% -8%, rgba(25, 215, 242, 0.18), transparent 55%),
    radial-gradient(700px 420px at 100% 8%, rgba(255, 122, 61, 0.12), transparent 50%),
    linear-gradient(180deg, var(--bg-glow) 0%, var(--bg) 42%, #050814 100%);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: var(--accent);
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 0 48px;
}

.hero {
  text-align: center;
  padding: 0 0 28px;
}

.hero-visual {
  position: relative;
  width: 100%;
  overflow: hidden;
  border-bottom: 1px solid var(--border);
  background: #00e8f8;
}

.hero-visual img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1932 / 828;
  object-fit: cover;
}

.hero-panel {
  padding: 28px 20px 0;
}

.hero-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 18px;
  text-align: left;
}

.hero img.icon {
  width: 84px;
  height: 84px;
  border-radius: 20px;
  box-shadow:
    0 0 0 1px rgba(25, 215, 242, 0.35),
    0 12px 32px rgba(0, 0, 0, 0.35);
  flex-shrink: 0;
}

.hero-titles h1 {
  font-size: clamp(1.45rem, 4.5vw, 1.85rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.hero-titles h1 .en {
  display: block;
  font-size: 0.72em;
  font-weight: 600;
  color: var(--text-sub);
  margin-top: 4px;
  letter-spacing: 0;
}

.badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--accent);
  margin-top: 6px;
}

.tagline {
  font-size: 1.05rem;
  color: var(--text-sub);
  margin-bottom: 24px;
  line-height: 1.55;
}

.tagline em {
  font-style: normal;
  color: var(--text);
  font-weight: 700;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 12px;
}

.btn-primary {
  display: inline-block;
  background: linear-gradient(135deg, var(--accent) 0%, #4aa8ff 100%);
  color: #061018 !important;
  text-decoration: none;
  font-weight: 800;
  font-size: 1rem;
  padding: 14px 28px;
  border-radius: 14px;
  box-shadow: 0 8px 24px rgba(25, 215, 242, 0.28);
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--accent-dim) 0%, #3a98ef 100%);
}

.cta-qr img {
  width: 88px;
  height: 88px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fff;
  display: block;
}

.cta-qr-label {
  display: block;
  font-size: 10px;
  color: var(--text-sub);
  margin-top: 6px;
}

.links-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px 20px;
  margin: 18px 0 8px;
  font-size: 13px;
  padding: 0 20px;
}

.section-inner {
  padding: 0 20px;
}

section {
  margin-top: 36px;
}

h2 {
  font-size: 1.15rem;
  font-weight: 800;
  margin-bottom: 14px;
  color: var(--accent);
  letter-spacing: -0.02em;
}

.features {
  display: grid;
  gap: 14px;
}

.feature {
  padding: 4px 0 14px;
  border-bottom: 1px solid var(--border);
}

.feature:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.feature strong {
  display: block;
  margin-bottom: 6px;
  font-size: 15px;
}

.feature p {
  font-size: 13px;
  color: var(--text-sub);
  margin: 0;
}

.faq details {
  border-top: 1px solid var(--border);
  padding: 14px 0;
}

.faq details:last-child {
  border-bottom: 1px solid var(--border);
}

.faq summary {
  cursor: pointer;
  font-weight: 700;
  font-size: 14px;
  list-style: none;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq p {
  margin-top: 8px;
  font-size: 13px;
  color: var(--text-sub);
}

.sources-intro {
  font-size: 0.9rem;
  color: var(--text-sub);
  line-height: 1.55;
  margin-bottom: 16px;
}

.changelog {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.changelog::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--border);
}

.changelog-item {
  position: relative;
  padding: 0 0 28px 36px;
}

.changelog-item:last-child {
  padding-bottom: 0;
}

.changelog-item::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--card);
  border: 3px solid var(--accent);
  box-sizing: border-box;
}

.changelog-item.is-latest::before {
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(25, 215, 242, 0.18);
}

.changelog-ver {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 12px;
  margin-bottom: 8px;
}

.changelog-ver strong {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.02em;
}

.changelog-meta {
  font-size: 0.78rem;
  color: var(--text-sub);
  font-weight: 600;
}

.changelog-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--accent);
  background: rgba(25, 215, 242, 0.12);
  padding: 2px 8px;
  border-radius: 999px;
}

.changelog-item ul {
  margin: 0;
  padding-left: 1.1em;
  color: var(--text-sub);
  font-size: 0.88rem;
  line-height: 1.55;
}

.changelog-item li {
  margin-bottom: 4px;
}

.changelog-item li:last-child {
  margin-bottom: 0;
}

.changelog-note {
  font-size: 0.8rem;
  color: var(--text-sub);
  margin-top: 16px;
  line-height: 1.5;
}

footer {
  margin: 48px 20px 0;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 13px;
  color: var(--text-sub);
}

footer p {
  margin-bottom: 8px;
}

.legal-meta {
  font-size: 13px;
  color: var(--text-sub);
  margin: 8px 0 24px;
}

.legal {
  padding: 24px 20px 48px;
}

.legal h1 {
  font-size: 1.6rem;
  font-weight: 800;
}

.legal h2 {
  margin-top: 28px;
}

.legal p,
.legal li {
  font-size: 14px;
  color: var(--text-sub);
}

.legal p {
  margin-bottom: 10px;
}

.legal ul {
  padding-left: 1.2em;
  margin-bottom: 12px;
}

.legal li {
  margin-bottom: 6px;
}

.back {
  display: inline-block;
  margin-bottom: 20px;
  font-size: 13px;
}

@media (max-width: 520px) {
  .hero-brand {
    flex-direction: column;
    text-align: center;
  }

  .hero-titles h1 .en {
    font-size: 0.68em;
  }
}