:root {
  --blue: #3182f6;
  --blue-dark: #1b64da;
  --text: #191f28;
  --sub: #4e5968;
  --muted: #8b95a1;
  --bg-alt: #f9fafb;
  --card: #f2f4f6;
  --radius: 24px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 64px; }
body {
  font-family: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.6;
  word-break: keep-all;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

/* Nav */
.nav {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255,255,255,.85);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid #f2f4f6;
}
.nav-inner { display: flex; align-items: center; height: 64px; gap: 32px; }
.logo { font-weight: 800; font-size: 20px; letter-spacing: -.02em; }
.logo span { color: var(--blue); margin-left: 4px; }
.nav-links { display: flex; gap: 24px; margin-right: auto; }
.nav-links a { color: var(--sub); font-weight: 500; font-size: 15px; }
.nav-links a:hover { color: var(--text); }

/* Buttons */
.btn {
  display: inline-block;
  background: var(--blue); color: #fff;
  font-weight: 600; font-size: 17px;
  padding: 16px 28px; border-radius: 16px;
  transition: background .2s, transform .2s;
}
.btn:hover { background: var(--blue-dark); }
.btn:active { transform: scale(.97); }
.btn-ghost { background: #e8f3ff; color: var(--blue); }
.btn-ghost:hover { background: #d0e6ff; }

/* Typography */
.eyebrow { color: var(--blue); font-weight: 700; font-size: 17px; margin-bottom: 12px; }
h1 { font-size: clamp(40px, 7vw, 72px); font-weight: 800; line-height: 1.25; letter-spacing: -.03em; }
h2 { font-size: clamp(30px, 4.5vw, 48px); font-weight: 800; line-height: 1.3; letter-spacing: -.03em; margin-bottom: 48px; }
h3 { font-size: 22px; font-weight: 700; letter-spacing: -.02em; }
.lead { font-size: clamp(18px, 2.2vw, 22px); color: var(--sub); margin: 24px 0 40px; }

.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* Banner */
.banner {
  display: block; color: #fff; overflow: hidden;
  background: radial-gradient(circle at 80% 30%, #3182f6 0, transparent 55%), linear-gradient(135deg, #0b1b3f, #12306e);
}
.banner-inner { display: grid; grid-template-columns: 1.1fr 1fr; align-items: center; gap: 48px; min-height: 560px; padding-top: 64px; padding-bottom: 64px; }
.banner:hover .btn { background: var(--blue-dark); }
.banner-tag { display: inline-block; font-size: 14px; font-weight: 600; padding: 6px 12px; border-radius: 8px; background: rgba(255,255,255,.14); }
.banner h2 { font-size: clamp(48px, 8vw, 84px); margin: 16px 0; }
.banner-text p { font-size: clamp(17px, 2vw, 20px); color: rgba(255,255,255,.8); margin-bottom: 36px; }

.chat { background: #fff; color: var(--text); border-radius: var(--radius); padding: 20px; box-shadow: 0 30px 60px rgba(0,0,0,.3); max-width: 420px; justify-self: end; width: 100%; }
.chat-tabs { display: flex; gap: 6px; margin-bottom: 20px; }
.chat-tabs span { font-size: 14px; font-weight: 600; padding: 6px 14px; border-radius: 10px; color: var(--muted); background: var(--card); }
.chat-tabs .on { background: var(--blue); color: #fff; }
.msg { margin-bottom: 14px; }
.msg b { display: block; font-size: 13px; color: var(--muted); font-weight: 600; }
.msg p { display: inline-block; background: var(--card); padding: 10px 14px; border-radius: 4px 16px 16px 16px; margin-top: 4px; }
.msg small { display: block; font-size: 13px; color: var(--blue); margin-top: 6px; }
.msg.me { text-align: right; margin-bottom: 0; }
.msg.me p { background: var(--blue); color: #fff; border-radius: 16px 4px 16px 16px; }

/* Sections */
.section { padding: 120px 0; }
.section.alt { background: var(--bg-alt); }
.grid { display: grid; gap: 20px; }
.card { background: #fff; border-radius: var(--radius); overflow: hidden; }
.section:not(.alt) .card { background: var(--card); }
.section-head { display: flex; align-items: baseline; gap: 16px; margin-bottom: 32px; }
.section-head h2 { font-size: clamp(26px, 3.5vw, 34px); margin: 0; }
.section-head a { color: var(--blue); font-weight: 600; font-size: 15px; }
.tag { display: inline-block; font-size: 13px; font-weight: 600; color: var(--blue); background: #e8f3ff; padding: 4px 10px; border-radius: 8px; margin-bottom: 12px; }
.link { color: var(--blue); font-weight: 600; font-size: 15px; }

/* Services */
.product { display: grid; grid-template-columns: minmax(200px, 2fr) 3fr; transition: transform .25s, box-shadow .25s; }
.product:hover { transform: translateY(-6px); box-shadow: 0 16px 40px rgba(0,27,55,.08); }
.product-art { display: grid; place-items: center; font-size: 80px; min-height: 240px; background: linear-gradient(135deg, #3182f6, #6cb4ff); }
.product-body { padding: 40px; align-self: center; }
.product-body h3 { font-size: 28px; }
.product-body p { color: var(--sub); margin: 12px 0 20px; }

/* CasualTalk */
.features { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
.feature { padding: 32px; }
.icon { font-size: 40px; margin-bottom: 20px; }
.feature p { color: var(--sub); margin-top: 8px; }
.sub { font-size: 28px; margin: 96px 0 24px; }
.engines { list-style: none; display: flex; flex-wrap: wrap; gap: 12px; }
.engines li { background: var(--card); padding: 14px 24px; border-radius: 14px; font-weight: 600; }
.notice { margin-top: 48px; padding: 20px 24px; border-radius: 16px; background: #e8f3ff; color: var(--blue-dark); font-weight: 500; }

/* CTA */
.cta { background: #191f28; color: #fff; padding: 96px 0; }
.cta h2 { margin-bottom: 12px; }
.cta p { color: rgba(255,255,255,.7); margin-bottom: 32px; font-size: 18px; }

/* Footer */
.footer { background: #111418; padding: 40px 0; color: #6b7684; font-size: 14px; border-top: 1px solid #2a2f37; }
.footer p { margin-top: 12px; }
.footer .logo { color: #b0b8c1; }

/* Reveal animation */
.reveal { opacity: 1; transform: none; }
.reveal.in { animation: reveal-in .7s ease; }
@keyframes reveal-in {
  from { opacity: 0; transform: translateY(28px); }
  to { opacity: 1; transform: none; }
}
@media (prefers-reduced-motion: reduce) {
  .reveal.in { animation: none; }
  html { scroll-behavior: auto; }
}

/* Mobile */
@media (max-width: 640px) {
  .nav-inner { gap: 16px; }
  .nav-links { gap: 16px; }
  .nav-links a { font-size: 14px; }
  .section { padding: 88px 0; }
  .banner-inner { grid-template-columns: 1fr; min-height: 0; }
  .chat { justify-self: stretch; }
  .product { grid-template-columns: 1fr; }
  .product-art { min-height: 180px; }
  .product-body { padding: 28px; }
}