/* =========================================================
   Bitwave Co., Ltd. — corporate site
   Aesthetic: editorial-tech / paper + ink + leather-tan
   ========================================================= */

@import url("https://cdn.jsdelivr.net/gh/orioncactus/pretendard@v1.3.9/dist/web/static/pretendard.css");
@import url("https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,400;0,9..144,500;1,9..144,400&display=swap");

:root {
  --paper: #f4f6f9;
  --paper-2: #e7eef4;
  --ink: #14223a;
  --ink-soft: #43546b;
  --ink-faint: #8493a6;
  --line: #d3dde7;
  --tan: #1f80b0;        /* brand blue accent (from logo) */
  --tan-deep: #155a83;
  --cyan: #33b1cf;       /* bright cyan from logo */
  --navy: #1c3a5e;       /* deep brand navy */
  --paper-card: #fbfcfe;
  --shadow: 24px 24px 60px rgba(20, 34, 58, 0.10);

  --font-display: "Fraunces", "Pretendard", Georgia, serif;
  --font-body: "Pretendard", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --font-mono: "Pretendard", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;

  --maxw: 1160px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

/* subtle paper grain + wave field */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(900px 600px at 85% -5%, rgba(51, 177, 207, 0.11), transparent 60%),
    radial-gradient(700px 500px at -5% 100%, rgba(28, 58, 94, 0.07), transparent 55%),
    var(--paper);
}
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  pointer-events: none;
}

a { color: inherit; text-decoration: none; }

.wrap { width: min(var(--maxw), 92vw); margin-inline: auto; }

.mono {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

/* ---------- nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--paper) 82%, transparent);
  border-bottom: 1px solid var(--line);
}
.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand__mark { width: 34px; height: 34px; display: block; }
.brand__word {
  font-family: var(--font-body);
  font-weight: 800;
  font-size: 1.42rem;
  letter-spacing: 0.05em;
  line-height: 1;
  background: linear-gradient(100deg, #1b3a5e 0%, #2a79ad 58%, #34a6c5 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: #1b3a5e;
}
.brand__name {
  font-family: var(--font-display);
  font-size: 1.32rem;
  font-weight: 500;
  letter-spacing: 0.01em;
}
.brand__name b { color: var(--tan); font-weight: 500; }
.nav__links { display: flex; gap: 34px; align-items: center; }
.nav__links a {
  font-size: 0.92rem;
  color: var(--ink-soft);
  position: relative;
  transition: color 0.25s;
}
.nav__links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: -6px;
  width: 0; height: 1.5px;
  background: var(--tan);
  transition: width 0.3s ease;
}
.nav__links a:hover { color: var(--ink); }
.nav__links a:hover::after { width: 100%; }
.nav__cta {
  border: 1px solid var(--ink);
  border-radius: 999px;
  padding: 9px 18px !important;
  color: var(--ink) !important;
}
.nav__cta::after { display: none; }
.nav__cta:hover { background: var(--ink); color: var(--paper) !important; }
.nav__toggle { display: none; background: none; border: 0; cursor: pointer; }

/* ---------- hero ---------- */
.hero { padding: clamp(70px, 12vw, 150px) 0 clamp(60px, 9vw, 110px); position: relative; }
.hero__kicker { margin-bottom: 28px; display: flex; align-items: center; gap: 14px; }
.hero__kicker .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--tan); display: inline-block; }
.hero__display {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(2.4rem, 6.4vw, 5.1rem);
  line-height: 1.02;
  letter-spacing: -0.018em;
}
.hero__display em { font-style: italic; color: var(--tan); }
.hero__lead {
  margin-top: 30px;
  max-width: 33ch;
  font-size: clamp(1.18rem, 2.5vw, 1.55rem);
  font-weight: 500;
  line-height: 1.45;
  color: var(--ink);
}
.hero__sub {
  margin-top: 22px;
  max-width: 56ch;
  color: var(--ink-soft);
  font-size: 1.02rem;
}
.hero__actions { margin-top: 42px; display: flex; gap: 18px; flex-wrap: wrap; align-items: center; }
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  font-size: 0.98rem; font-weight: 500;
  padding: 14px 26px; border-radius: 999px;
  transition: transform 0.25s, background 0.25s, color 0.25s;
}
.btn--primary { background: var(--ink); color: var(--paper); }
.btn--primary:hover { background: var(--tan-deep); transform: translateY(-2px); }
.btn--ghost { color: var(--ink); }
.btn--ghost:hover { color: var(--tan); gap: 16px; }

/* animated wave divider */
.wavefield { margin-top: 64px; width: 100%; height: 120px; overflow: hidden; opacity: 0.9; }
.wavefield svg { width: 100%; height: 100%; }
.wavefield path { fill: none; stroke: var(--line); stroke-width: 1.4; }
.wavefield path.accent { stroke: var(--tan); opacity: 0.5; }

/* ---------- sections ---------- */
section { padding: clamp(64px, 10vw, 120px) 0; }
.sec-head { display: flex; align-items: baseline; gap: 18px; margin-bottom: 48px; flex-wrap: wrap; }
.sec-head h2 {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(1.8rem, 4vw, 2.9rem);
  letter-spacing: -0.01em;
  line-height: 1.1;
}
.sec-head .num { color: var(--tan); }
.sec-lead { max-width: 64ch; margin: -22px 0 44px; color: var(--ink-soft); font-size: 1.07rem; line-height: 1.65; }
.sec-lead .hl { color: var(--tan-deep); font-weight: 500; }

/* about */
.about__grid { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 56px; align-items: start; }
.about__lead { font-size: clamp(1.25rem, 2.6vw, 1.7rem); font-weight: 500; line-height: 1.5; letter-spacing: -0.01em; }
.about__lead .hl { color: var(--tan); }
.about__body p { color: var(--ink-soft); margin-top: 18px; font-size: 1.02rem; }
.about__en { margin-top: 26px; font-family: var(--font-display); font-style: italic; color: var(--ink-faint); font-size: 1.05rem; line-height: 1.5; }
.facts { border-top: 1px solid var(--line); }
.facts__row { display: flex; justify-content: space-between; gap: 16px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.facts__row dt { color: var(--ink-faint); font-family: var(--font-mono); font-size: 0.74rem; letter-spacing: 0.12em; text-transform: uppercase; }
.facts__row dd { text-align: right; font-weight: 500; }

/* services */
.services { background: linear-gradient(180deg, transparent, var(--paper-2) 12%, var(--paper-2) 88%, transparent); }
.cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 26px; }
.card {
  position: relative;
  background: var(--paper-card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 34px 32px 30px;
  overflow: hidden;
  transition: transform 0.35s cubic-bezier(.2,.7,.2,1), box-shadow 0.35s, border-color 0.35s;
}
.card::before {
  content: "";
  position: absolute; left: 0; top: 0; bottom: 0;
  width: 3px; background: var(--tan);
  transform: scaleY(0); transform-origin: top;
  transition: transform 0.4s ease;
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow); border-color: color-mix(in srgb, var(--tan) 40%, var(--line)); }
.card:hover::before { transform: scaleY(1); }
.card__idx { font-family: var(--font-mono); font-size: 0.74rem; color: var(--tan); letter-spacing: 0.12em; }
.card__name {
  margin-top: 16px;
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  display: flex; align-items: center; gap: 10px;
}
.card__domain { font-family: var(--font-mono); font-size: 0.82rem; color: var(--ink-faint); margin-top: 4px; }
.card__desc { margin-top: 16px; color: var(--ink-soft); font-size: 0.98rem; }
.card__tags { margin-top: 22px; display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
  font-family: var(--font-mono);
  font-size: 0.68rem; letter-spacing: 0.06em;
  color: var(--navy);
  background: color-mix(in srgb, var(--navy) 8%, transparent);
  border: 1px solid color-mix(in srgb, var(--navy) 18%, transparent);
  padding: 5px 10px; border-radius: 999px;
}
.card__link { margin-top: 24px; display: inline-flex; align-items: center; gap: 8px; font-size: 0.9rem; font-weight: 500; color: var(--ink); transition: gap 0.25s, color 0.25s; }
.card:hover .card__link { color: var(--tan-deep); gap: 13px; }

/* approach / capabilities strip */
.cap { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.cap__item { padding-top: 24px; border-top: 2px solid var(--ink); }
.cap__item h3 { font-size: 1.18rem; font-weight: 600; margin-bottom: 10px; }
.cap__item p { color: var(--ink-soft); font-size: 0.97rem; }

/* contact */
.contact { background: var(--ink); color: var(--paper); border-radius: 28px; padding: clamp(40px, 6vw, 72px); }
.contact .sec-head h2 { color: var(--paper); }
.contact .mono { color: color-mix(in srgb, var(--paper) 60%, transparent); }
.contact__grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: end; }
.contact__big { font-family: var(--font-display); font-size: clamp(1.7rem, 3.6vw, 2.6rem); font-weight: 400; line-height: 1.2; letter-spacing: -0.01em; }
.contact__big a { color: var(--tan); border-bottom: 1px solid color-mix(in srgb, var(--tan) 50%, transparent); }
.cdl { display: grid; gap: 0; }
.cdl__row { display: grid; grid-template-columns: 130px 1fr; gap: 16px; padding: 16px 0; border-top: 1px solid color-mix(in srgb, var(--paper) 16%, transparent); }
.cdl__row dt { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.12em; text-transform: uppercase; color: color-mix(in srgb, var(--paper) 55%, transparent); }
.cdl__row dd { color: var(--paper); }
.cdl__row dd a:hover { color: var(--tan); }

/* footer */
.footer { padding: 64px 0 50px; border-top: 1px solid var(--line); margin-top: 30px; }
.footer__top { display: flex; justify-content: space-between; gap: 30px; flex-wrap: wrap; align-items: flex-start; }
.footer__legal { max-width: 44ch; }
.footer__legal .brand__word { font-size: 1.55rem; display: inline-block; margin-bottom: 13px; }
.footer__legal .name { font-family: var(--font-display); font-size: 1.25rem; font-weight: 500; }
.footer__legal .name b { color: var(--tan); font-weight: 500; }
.footer__legal p { color: var(--ink-faint); font-size: 0.86rem; margin-top: 10px; line-height: 1.7; }
.footer__links { display: flex; gap: 28px; flex-wrap: wrap; }
.footer__links a { font-size: 0.9rem; color: var(--ink-soft); }
.footer__links a:hover { color: var(--tan); }
.footer__bottom { margin-top: 40px; display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; color: var(--ink-faint); font-size: 0.8rem; }
.biz-verify { color: var(--tan); white-space: nowrap; border-bottom: 1px solid color-mix(in srgb, var(--tan) 45%, transparent); transition: color 0.2s; }
.biz-verify:hover { color: var(--tan-deep); }

/* ---------- reveal animation ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.8s cubic-bezier(.2,.7,.2,1), transform 0.8s cubic-bezier(.2,.7,.2,1); }
.reveal.in { opacity: 1; transform: none; }
.stagger > * { opacity: 0; transform: translateY(20px); }
.stagger.in > * { animation: rise 0.7s cubic-bezier(.2,.7,.2,1) forwards; }
.stagger.in > *:nth-child(1) { animation-delay: 0.05s; }
.stagger.in > *:nth-child(2) { animation-delay: 0.15s; }
.stagger.in > *:nth-child(3) { animation-delay: 0.25s; }
.stagger.in > *:nth-child(4) { animation-delay: 0.35s; }
@keyframes rise { to { opacity: 1; transform: none; } }

@media (prefers-reduced-motion: reduce) {
  .reveal, .stagger > * { opacity: 1 !important; transform: none !important; transition: none; animation: none; }
  html { scroll-behavior: auto; }
}

/* ---------- legal pages ---------- */
.legal { padding: clamp(60px, 9vw, 110px) 0 90px; }
.legal__head { margin-bottom: 50px; }
.legal__head h1 { font-family: var(--font-display); font-weight: 400; font-size: clamp(2rem, 5vw, 3.2rem); letter-spacing: -0.015em; }
.legal__body { max-width: 760px; }
.legal__body h2 { font-size: 1.2rem; margin: 38px 0 12px; font-weight: 600; }
.legal__body h2 .n { color: var(--tan); font-family: var(--font-mono); font-size: 0.9rem; margin-right: 8px; }
.legal__body p, .legal__body li { color: var(--ink-soft); font-size: 0.98rem; margin-top: 10px; }
.legal__body ul { margin-left: 20px; }
.legal__body .updated { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-faint); letter-spacing: 0.08em; }
.legal__body table { width: 100%; border-collapse: collapse; margin-top: 16px; font-size: 0.92rem; }
.legal__body th, .legal__body td { border: 1px solid var(--line); padding: 10px 12px; text-align: left; }
.legal__body th { background: var(--paper-2); font-weight: 600; }
.back { display: inline-flex; align-items: center; gap: 8px; margin-top: 50px; font-weight: 500; color: var(--tan-deep); }
.back:hover { gap: 13px; }

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .nav__links { position: fixed; inset: 70px 0 auto 0; flex-direction: column; gap: 0; background: var(--paper); border-bottom: 1px solid var(--line); padding: 10px 6vw 24px; transform: translateY(-130%); transition: transform 0.4s cubic-bezier(.2,.7,.2,1); }
  .nav__links.open { transform: none; }
  .nav__links a { padding: 14px 0; width: 100%; border-bottom: 1px solid var(--line); }
  .nav__links a::after { display: none; }
  .nav__cta { text-align: center; border-radius: 12px; margin-top: 12px; }
  .nav__toggle { display: block; }
  .brand__word { font-size: 1.24rem; }
  .about__grid { grid-template-columns: 1fr; gap: 40px; }
  .cards { grid-template-columns: 1fr; }
  .cap { grid-template-columns: 1fr; gap: 24px; }
  .contact__grid { grid-template-columns: 1fr; gap: 34px; align-items: start; }
}