/* =============================================================
   DATATREE Inc. — Modern Corporate Website
   Design System / Global Styles
   ============================================================= */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@400;500;600;700;800&family=Noto+Sans+KR:wght@400;500;600;700;800;900&display=swap');

:root{
  /* Brand colors (derived from datatree21.com identity) */
  --brand-blue: #4387f0;
  --brand-blue-dark: #2c5fc7;
  --brand-blue-deep: #16224e;
  --brand-navy: #0b1638;
  --brand-cyan: #34d6c4;
  --brand-orange: #ff9d3d;
  --brand-yellow: #ffce54;

  --text-dark: #16192b;
  --text-body: #4a4f63;
  --text-muted: #8a8fa3;
  --bg-light: #f5f8fd;
  --bg-soft: #eef3fc;
  --white: #ffffff;

  --gradient-brand: linear-gradient(135deg, #4387f0 0%, #34d6c4 100%);
  --gradient-dark: linear-gradient(135deg, #0b1638 0%, #16224e 55%, #2c5fc7 100%);
  --gradient-orange: linear-gradient(135deg, #ff9d3d 0%, #ffce54 100%);

  --shadow-soft: 0 10px 30px rgba(20, 40, 100, 0.08);
  --shadow-card: 0 15px 40px rgba(20, 40, 100, 0.10);
  --shadow-hover: 0 25px 55px rgba(20, 40, 100, 0.18);

  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 999px;

  --container: 1240px;
  --header-h: 84px;

  --ease: cubic-bezier(.22, 1, .36, 1);
}

*, *::before, *::after{ box-sizing: border-box; }
html{ scroll-behavior: smooth; scroll-padding-top: var(--header-h); }
body{
  margin: 0;
  font-family: 'Noto Sans KR', 'Manrope', sans-serif;
  color: var(--text-body);
  background: var(--white);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img{ max-width: 100%; display: block; }
a{ color: inherit; text-decoration: none; }
ul{ margin: 0; padding: 0; list-style: none; }
h1,h2,h3,h4,h5{ margin: 0; font-family: 'Noto Sans KR', sans-serif; color: var(--text-dark); }
p{ margin: 0; }
button{ font-family: inherit; cursor: pointer; }
.container{ max-width: var(--container); margin: 0 auto; padding: 0 24px; }

/* ---------- Utility ---------- */
.eyebrow{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: 'Manrope', sans-serif;
  font-weight: 700;
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  color: var(--brand-blue);
  background: var(--bg-soft);
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  margin-bottom: 20px;
}
.eyebrow::before{
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--brand-cyan);
  display: inline-block;
}
.section-head{ text-align: center; max-width: 700px; margin: 0 auto 56px; }
.section-head h2{ font-size: clamp(1.8rem, 3.2vw, 2.6rem); font-weight: 800; line-height: 1.3; }
.section-head p{ margin-top: 14px; color: var(--text-muted); font-size: 1.02rem; }
.section-pad{ padding: 110px 0; }
.text-center{ text-align: center; }

.btn{
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 15px 32px;
  border-radius: var(--radius-pill);
  border: none;
  transition: all .35s var(--ease);
  white-space: nowrap;
}
.btn-primary{ background: var(--gradient-brand); color: #fff; box-shadow: 0 12px 28px rgba(67,135,240,.35); }
.btn-primary:hover{ transform: translateY(-3px); box-shadow: 0 18px 36px rgba(67,135,240,.45); }
.btn-outline{ background: transparent; border: 1.5px solid rgba(255,255,255,.5); color: #fff; }
.btn-outline:hover{ background: rgba(255,255,255,.12); }
.btn-dark{ background: var(--brand-navy); color: #fff; }
.btn-dark:hover{ transform: translateY(-3px); box-shadow: var(--shadow-hover); }

/* ---------- Header ---------- */
.site-header{
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  z-index: 999;
  background: rgba(255,255,255,0);
  transition: background .35s var(--ease), box-shadow .35s var(--ease), height .3s var(--ease);
}
.site-header.scrolled{
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(14px);
  box-shadow: 0 4px 30px rgba(20,40,100,.08);
  height: 72px;
}
.header-inner{
  max-width: var(--container);
  margin: 0 auto;
  height: 100%;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}
.logo-link{ display: flex; align-items: center; height: 40px; }
.logo-img{
  height: 34px; width: auto;
  transition: filter .3s var(--ease);
  /* Default: header is transparent over dark hero, show logo in white */
  filter: brightness(0) invert(1) drop-shadow(0 1px 4px rgba(0,0,0,.3));
}
.site-header.scrolled .logo-img{
  /* Scrolled: header is white/blurred, show logo in original brand color */
  filter: none;
}

/* Default state: header floats transparently over a dark hero image,
   so nav text must be WHITE with a soft shadow for legibility.       */
.main-nav ul{ display: flex; gap: 44px; }
.main-nav a{
  font-family: 'Manrope', sans-serif;
  font-weight: 700;
  font-size: 0.9rem;
  letter-spacing: 0.06em;
  color: #fff;
  text-shadow: 0 1px 6px rgba(0,0,0,.35);
  position: relative;
  padding: 8px 0;
  transition: color .3s var(--ease), text-shadow .3s var(--ease);
}
.main-nav a::after{
  content: '';
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--gradient-brand);
  transition: width .3s var(--ease);
}
.main-nav a:hover::after,
.main-nav a.active::after{ width: 100%; }
.main-nav a:hover{ color: #fff; }
.main-nav a.active{ color: var(--brand-cyan); }

/* Scrolled state: header background turns white/blurred,
   so nav text switches to dark for contrast.                        */
.site-header.scrolled .main-nav a{ color: var(--text-dark); text-shadow: none; }
.site-header.scrolled .main-nav a:hover{ color: var(--brand-blue); }
.site-header.scrolled .main-nav a.active{ color: var(--brand-blue); }

.header-cta{
  background: var(--gradient-brand);
  color: #fff;
  font-weight: 700;
  font-size: 0.88rem;
  padding: 12px 24px;
  border-radius: var(--radius-pill);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: transform .3s var(--ease), box-shadow .3s var(--ease);
  box-shadow: 0 10px 22px rgba(67,135,240,.3);
}
.header-cta:hover{ transform: translateY(-2px); box-shadow: 0 14px 26px rgba(67,135,240,.4); }

.mobile-menu-btn{
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 34px; height: 34px;
  background: transparent;
  border: none;
  z-index: 1001;
}
.mobile-menu-btn .line{
  width: 100%; height: 2px;
  background: #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,.3);
  border-radius: 2px;
  transition: all .3s var(--ease);
}
.site-header.scrolled .mobile-menu-btn .line{ background: var(--text-dark); box-shadow: none; }
.mobile-menu-btn.open .line:nth-child(1){ transform: translateY(7px) rotate(45deg); }
.mobile-menu-btn.open .line:nth-child(2){ opacity: 0; }
.mobile-menu-btn.open .line:nth-child(3){ transform: translateY(-7px) rotate(-45deg); }

.mobile-menu{
  position: fixed;
  top: 0; right: -100%;
  width: min(78vw, 340px);
  height: 100vh;
  background: var(--brand-navy);
  z-index: 1000;
  padding: 110px 40px 40px;
  transition: right .4s var(--ease);
}
.mobile-menu.open{ right: 0; }
.mobile-menu ul{ display: flex; flex-direction: column; gap: 8px; }
.mobile-menu a{
  color: #fff;
  font-family: 'Manrope', sans-serif;
  font-weight: 700;
  font-size: 1.3rem;
  padding: 14px 0;
  display: block;
  border-bottom: 1px solid rgba(255,255,255,.08);
}

@media (max-width: 960px){
  .main-nav, .header-cta{ display: none; }
  .mobile-menu-btn{ display: flex; }
}

/* ---------- Page Hero (inner pages) ---------- */
.page-hero{
  position: relative;
  padding: calc(var(--header-h) + 100px) 0 90px;
  background: var(--gradient-dark);
  overflow: hidden;
  color: #fff;
}
.page-hero::before{
  content: '';
  position: absolute; inset: 0;
  background:
    radial-gradient(circle at 15% 20%, rgba(67,135,240,.35), transparent 45%),
    radial-gradient(circle at 85% 80%, rgba(52,214,196,.25), transparent 50%);
}
.page-hero .container{ position: relative; z-index: 2; }
.page-hero .crumbs{
  font-family: 'Manrope',sans-serif;
  font-weight: 600;
  font-size: .85rem;
  color: rgba(255,255,255,.65);
  letter-spacing: .05em;
  margin-bottom: 18px;
}
.page-hero .crumbs a{ color: rgba(255,255,255,.65); }
.page-hero .crumbs a:hover{ color: #fff; }
.page-hero h1{
  color: #fff;
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  font-weight: 800;
  margin-bottom: 16px;
}
.page-hero p{
  color: rgba(255,255,255,.75);
  max-width: 620px;
  font-size: 1.08rem;
}
.page-hero .eng-tag{
  font-family: 'Manrope',sans-serif;
  color: var(--brand-cyan);
  font-weight: 700;
  letter-spacing: .18em;
  font-size: .9rem;
  margin-bottom: 10px;
  display: block;
}

/* ---------- Footer ---------- */
.site-footer{
  background: var(--brand-navy);
  color: rgba(255,255,255,.7);
  padding: 80px 0 30px;
  position: relative;
}
.footer-inner{ max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.footer-top{
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 50px;
  padding-bottom: 50px;
}
.footer-logo{ height: 30px; filter: brightness(0) invert(1); margin-bottom: 16px; }
.footer-slogan{
  font-family: 'Manrope', sans-serif;
  font-weight: 700;
  letter-spacing: .06em;
  color: rgba(255,255,255,.5);
  font-size: .85rem;
}
.footer-nav{ display: flex; gap: 70px; flex-wrap: wrap; }
.footer-col h4{
  color: #fff;
  font-size: .82rem;
  letter-spacing: .1em;
  margin-bottom: 18px;
  font-family: 'Manrope',sans-serif;
}
.footer-col a{ display: block; margin-bottom: 12px; font-size: .92rem; color: rgba(255,255,255,.6); transition: color .25s; }
.footer-col a:hover{ color: var(--brand-cyan); }
.footer-divider{ height: 1px; background: rgba(255,255,255,.1); margin-bottom: 30px; }
.footer-bottom{ display: flex; justify-content: space-between; flex-wrap: wrap; gap: 20px; }
.footer-address{ font-style: normal; display: flex; flex-direction: column; gap: 6px; font-size: .87rem; color: rgba(255,255,255,.55); }
.footer-legal{ text-align: right; }
.footer-links{ display: flex; gap: 18px; justify-content: flex-end; margin-bottom: 10px; }
.footer-links a{ font-size: .85rem; color: rgba(255,255,255,.6); }
.footer-links a:hover{ color: #fff; }
.copyright{ font-size: .8rem; color: rgba(255,255,255,.4); }

@media (max-width: 700px){
  .footer-bottom{ flex-direction: column; }
  .footer-legal{ text-align: left; }
  .footer-links{ justify-content: flex-start; }
}

.btn-top{
  position: fixed;
  right: 30px; bottom: 30px;
  width: 48px; height: 48px;
  border-radius: 50%;
  border: none;
  background: var(--gradient-brand);
  color: #fff;
  font-size: 1.1rem;
  box-shadow: 0 10px 25px rgba(67,135,240,.4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all .3s var(--ease);
  z-index: 800;
}
.btn-top.show{ opacity: 1; visibility: visible; transform: translateY(0); }
.btn-top:hover{ transform: translateY(-4px); }

/* ---------- Scroll Reveal ---------- */
.reveal{
  opacity: 0;
  transform: translateY(36px);
  transition: opacity .8s var(--ease), transform .8s var(--ease);
}
.reveal.show{ opacity: 1; transform: translateY(0); }
.reveal-delay-1{ transition-delay: .1s; }
.reveal-delay-2{ transition-delay: .22s; }
.reveal-delay-3{ transition-delay: .34s; }
.reveal-delay-4{ transition-delay: .46s; }

/* ---------- Marquee (Partners) ---------- */
.marquee-wrap{
  overflow: hidden;
  position: relative;
  padding: 20px 0;
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 6%, #000 94%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 6%, #000 94%, transparent);
}
.marquee-track{ display: flex; gap: 50px; width: max-content; animation: marquee 44s linear infinite; align-items: center; }
.marquee-wrap:hover .marquee-track{ animation-play-state: paused; }
.marquee-track img{
  height: 120px;
  width: auto;
  max-width: 260px;
  object-fit: contain;
  opacity: .8;
  filter: grayscale(35%);
  transition: opacity .3s, filter .3s, transform .3s var(--ease);
  background: #fff;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  padding: 14px 22px;
}
.marquee-track img:hover{ opacity: 1; filter: grayscale(0%); transform: translateY(-4px); }
@keyframes marquee{ from{ transform: translateX(0);} to{ transform: translateX(-50%);} }

@media (max-width: 700px){
  .marquee-track img{ height: 88px; max-width: 190px; padding: 10px 16px; }
  .marquee-track{ gap: 34px; }
}

/* ---------- Back to top of page (scroll progress) ---------- */
#scrollProgress{
  position: fixed; top: 0; left: 0; height: 3px;
  background: var(--gradient-brand);
  z-index: 1100; width: 0%;
  transition: width .1s linear;
}