/* ============================================================
   euidos.ai — base.css
   reset · 컨테이너 · 스티키 nav · footer · 버튼 · 섹션 리듬 · 공통 타이틀
   섹션별 스타일은 각 섹션 root id 하위로 스코프(전역 오염 금지).
   ============================================================ */

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
/* overflow-x: clip 은 가로 넘침만 잘라내고 스크롤 컨테이너를 만들지 않아 sticky nav 가 정상 동작한다 (hidden 은 sticky 를 깨뜨림) */
html, body { overflow-x: clip; }
body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--ink-2);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
ul { list-style: none; }
:focus-visible { outline: 2px solid var(--c-indigo); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* ---------- 컨테이너 ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

/* ---------- 섹션 리듬 ---------- */
.section { padding-block: var(--section-pad-y); position: relative; }
.section--tint { background: var(--bg-tint); }
/* 스티키 nav 높이만큼 앵커 오프셋 */
main > section[id],
section[id] { scroll-margin-top: 72px; }

/* ---------- 공통 eyebrow / 섹션 타이틀 ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: var(--fs-label);
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--c-indigo);
  text-transform: none;
}
.section-title {
  font-size: var(--fs-h2);
  line-height: var(--lh-tight);
  font-weight: 800;
  letter-spacing: -.03em;
  color: var(--ink);
  word-break: keep-all;
  margin-top: var(--space-3);
}
.section-sub {
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--ink-2);
  max-width: 42em;
  margin-top: var(--space-4);
  word-break: keep-all;
}
.section-head { margin-bottom: var(--space-7); max-width: 46rem; }
.grad-text {
  background: var(--grad-tri);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ---------- 버튼 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: .95rem;
  font-weight: 700;
  line-height: 1;
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 13px 24px;
  transition: transform .2s var(--ease), box-shadow .2s var(--ease), border-color .2s;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  color: #fff;
  background: linear-gradient(94deg, #0ea5a4 0%, var(--c-indigo) 60%, var(--c-violet) 110%);
  box-shadow: var(--shadow-cta);
}
.btn-primary:hover { box-shadow: 0 14px 32px -8px rgba(79,70,229,.65); }
.btn-ghost {
  color: var(--ink);
  background: var(--panel);
  border-color: var(--line);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.btn-ghost:hover { border-color: rgba(99,102,241,.4); }
.btn-sm { padding: 9px 16px; font-size: .86rem; border-radius: var(--radius-pill); }

/* ---------- 스티키 nav (얇음) ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(243,246,251,.75);
  backdrop-filter: blur(14px) saturate(1.2);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  border-bottom: 1px solid var(--line-soft);
}
.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  height: 56px;
}
.site-nav__brand {
  font-weight: 800;
  font-size: 1.18rem;
  letter-spacing: -.02em;
  color: var(--ink);
}
.site-nav__brand b {
  font-weight: 800;
  background: var(--grad-tri);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.site-nav__menu {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 28px);
}
.site-nav__menu a:not(.btn) {
  font-size: .9rem;
  font-weight: 600;
  color: var(--ink-2);
  transition: color .2s;
}
.site-nav__menu a:not(.btn):hover { color: var(--ink); }

/* 모바일 햄버거 (CSS-only 토글) */
.site-nav__toggle { display: none; }
.site-nav__burger {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--panel);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
}
.site-nav__burger span {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: var(--ink);
  transition: transform .25s var(--ease), opacity .2s;
}

@media (max-width: 820px) {
  .site-nav__burger { display: inline-flex; }
  .site-nav__menu {
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 12px var(--container-pad) 20px;
    background: rgba(243,246,251,.97);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    transition: transform .25s var(--ease), opacity .2s;
  }
  .site-nav__menu a:not(.btn) { padding: 10px 4px; }
  .site-nav__menu .btn { margin-top: 6px; }
  .site-nav__toggle:checked ~ .site-nav__menu {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .site-nav__toggle:checked ~ .site-nav__burger span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .site-nav__toggle:checked ~ .site-nav__burger span:nth-child(2) { opacity: 0; }
  .site-nav__toggle:checked ~ .site-nav__burger span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
}

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-tint);
  padding-block: var(--space-8) var(--space-7);
}
.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4) var(--space-6);
  align-items: baseline;
  justify-content: space-between;
}
.site-footer__brand {
  font-weight: 800;
  font-size: 1.05rem;
  color: var(--ink);
  letter-spacing: -.02em;
}
.site-footer__meta {
  font-size: var(--fs-sm);
  color: var(--ink-3);
  line-height: 1.7;
  font-style: normal; /* <address> is italic by default in every browser */
}
.site-footer__meta span { display: inline-block; }
/* contact links stay quiet in the footer; underline only on interaction */
.site-footer__meta a {
  color: inherit;
  text-decoration: none;
}
.site-footer__meta a:hover,
.site-footer__meta a:focus-visible { text-decoration: underline; }
.site-footer__copy {
  width: 100%;
  margin-top: var(--space-5);
  padding-top: var(--space-4);
  border-top: 1px solid var(--line-soft);
  font-size: .82rem;
  color: var(--ink-3);
}