*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-snap-type: y mandatory;
  scroll-padding-top: var(--header-height);
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 400;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-navy-deep);
  letter-spacing: 0.01em;
}

#main {
  position: relative;
  z-index: 1;
}

html[lang="ja"] body {
  line-height: 1.8;
}

img,
iframe {
  max-width: 100%;
  display: block;
}

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

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

address {
  font-style: normal;
}

.container {
  width: min(100% - 2.5rem, var(--container-max));
  margin-inline: auto;
}

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

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 300;
  padding: 0.5rem 1rem;
  background: var(--color-primary);
  color: #fff;
  font-size: 0.85rem;
}

.skip-link:focus {
  top: 1rem;
}

/* Header — 글래스 (전역 다크 배경) */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(8, 24, 40, 0.65);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(46, 134, 193, 0.15);
  transition: background var(--transition), box-shadow var(--transition);
}

.site-header.is-scrolled {
  background: rgba(8, 24, 40, 0.92);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.2);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-height: var(--header-height);
}

.logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  text-decoration: none;
}

.logo:hover {
  text-decoration: none;
  opacity: 0.92;
}

.logo-img {
  display: block;
  height: 60px;
  width: auto;
  max-width: min(300px, 58vw);
}

.logo-img--footer {
  height: 52px;
  max-width: 260px;
  margin: 0 auto var(--space-sm);
  border-radius: 8px;
}

.nav {
  flex: 1;
  display: flex;
  justify-content: center;
}

.nav-list {
  display: flex;
  gap: 1.75rem;
}

.nav-list a {
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(234, 244, 251, 0.72);
  transition: color var(--transition);
}

.nav-list a:hover,
.nav-list a.is-active {
  color: #fff;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
}

.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
}

.menu-bar {
  display: block;
  width: 20px;
  height: 1.5px;
  background: #eaf4fb;
  margin-inline: auto;
  transition: transform var(--transition), opacity var(--transition);
}

/* Full-page scroll snap */
.snap-page {
  scroll-snap-align: start;
  scroll-snap-stop: always;
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-sizing: border-box;
}

.snap-page--tall {
  justify-content: flex-start;
  padding-top: calc(var(--header-height) + var(--space-md));
}

.snap-page--footer {
  min-height: auto;
  scroll-snap-align: end;
  justify-content: center;
}

.snap-page__inner {
  width: 100%;
  max-height: calc(100dvh - var(--header-height) - var(--space-lg));
  overflow-y: auto;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.intro-why {
  margin-top: var(--space-2xl);
  padding-top: var(--space-2xl);
  border-top: 1px solid var(--color-line);
}

.section-title--sm {
  font-size: clamp(1.35rem, 3vw, 2rem);
}

/* Sections */
.section {
  padding: var(--space-4xl) 0;
}

.snap-page.section {
  padding: calc(var(--header-height) + var(--space-lg)) 0 var(--space-xl);
}

.section--center {
  text-align: center;
}

.section--soft {
  background: rgba(8, 24, 40, 0.35);
  backdrop-filter: blur(6px);
}

.section-en {
  margin: 0 0 0.75rem;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.28em;
  color: var(--color-accent);
  text-transform: uppercase;
}

.section-title {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4.5vw, 2.75rem);
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: #fff;
}

.section-sub,
.section-lead {
  margin: 0 auto;
  max-width: 640px;
  color: var(--color-text-muted);
  font-size: 1rem;
}

.section-lead {
  font-size: 1.05rem;
  line-height: 1.85;
}

.section-note {
  margin: 1.5rem auto 0;
  max-width: 560px;
  font-size: 0.8rem;
  color: var(--color-text-light);
}

.section-head {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

/* Footer */
.site-footer {
  position: relative;
  z-index: 1;
  padding: var(--space-2xl) 0;
  background: rgba(8, 24, 40, 0.75);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--color-line);
  color: rgba(174, 214, 241, 0.65);
  font-size: 0.8rem;
  text-align: center;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

.footer-copy {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.footer-privacy {
  background: none;
  border: none;
  color: rgba(174, 214, 241, 0.55);
  font-size: 0.75rem;
  cursor: pointer;
  text-decoration: underline;
  font-family: inherit;
}

.footer-privacy:hover {
  color: var(--color-accent);
}

.btn-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 90;
  width: 48px;
  height: 48px;
  border: 1px solid var(--color-line);
  background: rgba(8, 24, 40, 0.85);
  backdrop-filter: blur(10px);
  color: var(--color-text-muted);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition), border-color var(--transition);
}

.btn-top.is-visible {
  opacity: 1;
  visibility: visible;
}

.btn-top:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 900px) {
  .nav {
    position: fixed;
    inset: var(--header-height) 0 auto 0;
    background: rgba(8, 24, 40, 0.97);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--color-line);
    padding: 1.5rem;
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition), opacity var(--transition);
    justify-content: flex-start;
  }

  body.menu-open .nav {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-list {
    flex-direction: column;
    gap: 1rem;
  }

  .nav-list a {
    font-size: 0.85rem;
  }

  .menu-toggle {
    display: flex;
  }

  body.menu-open .menu-bar:nth-child(1) {
    transform: translateY(6.5px) rotate(45deg);
  }

  body.menu-open .menu-bar:nth-child(2) {
    opacity: 0;
  }

  body.menu-open .menu-bar:nth-child(3) {
    transform: translateY(-6.5px) rotate(-45deg);
  }

  .header-cta {
    display: none;
  }

  .logo-img {
    height: 48px;
    max-width: 62vw;
  }

  .section {
    padding: var(--space-3xl) 0;
  }
}