:root {
  --header-bg: #00326d;
  --header-bg-scrolled: rgba(10, 61, 107, 0.92);
  --white: #ffffff;
  --shadow: 0 16px 40px rgba(0, 0, 0, 0.18);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  scroll-behavior: smooth;
}

body {
  font-family:
    "Segoe UI", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  background: #ffffff;
  color: #121212;
}

body.menu-open {
  overflow: hidden;
}
a {
  color: inherit;
  text-decoration: none;
}
img {
  display: block;
  width: 100%;
  height: auto;
}
button {
  font: inherit;
}

.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;
}

/* ── Header ── */
.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 1000;
  background: var(--header-bg);
  padding: 20px 0;
  transition:
    padding 0.3s ease,
    background-color 0.3s ease;
}

body.scrolled .site-header {
  padding: 12px 0;
  background: var(--header-bg-scrolled);
  backdrop-filter: blur(10px);
}

.header-wrap {
  width: min(1200px, calc(100% - 32px));
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo {
  flex: 0 0 auto;
}
.logo img {
  width: 120px;
}

.navmenu {
  margin-left: auto;
}
.navmenu ul {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
}

.navmenu a {
  display: inline-flex;
  align-items: center;
  padding: 14px 16px;
  color: var(--white);
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.02em;
  transition: opacity 0.2s ease;
}

.navmenu a:hover,
.navmenu a:focus-visible {
  opacity: 0.78;
}

.mobile-nav-toggle {
  display: none;
  position: relative;
  width: 44px;
  height: 44px;
  border: 0;
  background: transparent;
  color: var(--white);
  cursor: pointer;
}

.mobile-nav-toggle span {
  position: absolute;
  left: 8px;
  right: 8px;
  height: 2px;
  background: currentColor;
  border-radius: 999px;
  transition:
    transform 0.25s ease,
    opacity 0.25s ease,
    top 0.25s ease;
}

.mobile-nav-toggle span:nth-child(1) {
  top: 13px;
}
.mobile-nav-toggle span:nth-child(2) {
  top: 21px;
}
.mobile-nav-toggle span:nth-child(3) {
  top: 29px;
}

body.menu-open .mobile-nav-toggle span:nth-child(1) {
  top: 21px;
  transform: rotate(45deg);
}
body.menu-open .mobile-nav-toggle span:nth-child(2) {
  opacity: 0;
}
body.menu-open .mobile-nav-toggle span:nth-child(3) {
  top: 21px;
  transform: rotate(-45deg);
}

/* ── Sections ── */
.section {
  padding: 80px 0;
  scroll-margin-top: 70px;
}

.section-img {
  width: min(800px, 100%);
  margin: 0 auto;
  display: block;
}

.section-full {
  width: 100%;
  margin: 0 auto;
  display: block;
}

/* Hero */
.hero {
  position: relative;
  background: #0072c6 url("../img/01.png?v=2") center bottom / 100% auto
    no-repeat;
  min-height: 100vh;
  padding: 87px 0 120px;
  margin-top: 87px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-content {
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
}
.hero-content > img {
  max-width: 800px;
  margin: 0 auto;
}

/* Why ATD */
.why-atd {
  background: #ffffff;
}

/* Benefits (dark) */
.benefits {
  background: #0d0d0d;
}

/* Schedule */
.schedule {
  background: #ffffff;
  position: relative;
  padding-bottom: 0;
}

.schedule > [data-reveal] {
  position: relative;
  z-index: 2;
}

.schedule-art {
  position: relative;
  margin-top: -10%;
  line-height: 0;
  z-index: 0;
  pointer-events: none;
}

/* Educator (dark) */
.educator {
  background: #0d0d0d;
}

.educator-wrap {
  position: relative;
  width: min(800px, 100%);
  margin: 0 auto;
}

.speak-link {
  position: absolute;
  left: 6%;
  top: 14.5%;
  width: 32%;
  height: 3%;
  display: block;
  z-index: 10;
  cursor: pointer;
}

/* Debriefing */
.debriefing {
  background: #d9eaf9;
  position: relative;
  overflow: hidden;
}

.debriefing-inner {
  position: relative;
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
  z-index: 1;
}
.debriefing-inner > img {
  max-width: 700px;
  margin: 0 auto;
}
.deco-left,
.deco-right {
  position: absolute;
  width: 25%;
  max-width: 300px;
  z-index: 0;
}

.deco-left {
  left: 0;
  top: 0;
}
.deco-right {
  right: 0;
  bottom: 0;
}

/* Pricing */
.pricing {
  background: #ffffff;
}

/* Brochure */
.brochure {
  background: #00326d;
  padding: 60px 0;
}

.brochure-inner {
  position: relative;
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
}

.brochure-link {
  position: absolute;
  right: 0;
  top: 0;
  width: 26%;
  height: 100%;
  display: block;
}

/* CTA */
.cta {
  background: #d9eaf9;
}

.cta-inner {
  position: relative;
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
}

.cta-apply-link {
  position: absolute;
  right: 0;
  top: 32%;
  width: 26%;
  height: 34%;
  display: block;
  border-radius: 12px;
}

/* Bottom art */
.bottom-art {
  background: #d9eaf9;
  line-height: 0;
  margin-top: -10%;
}

/* Footer */
.footer {
  background: #000000;
  padding: 20px 0;
}

.footer-content {
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
  text-align: center;
  padding: 30px 0;
}

.footer-logo {
  width: auto;
  max-width: 160px;
  margin: 0 auto 16px;
}

.footer-info {
  color: #aaa;
  font-size: 13px;
  line-height: 1.8;
  margin-bottom: 4px;
}

.footer-copy {
  color: #888;
  font-size: 12px;
  line-height: 1.8;
}

/* Reveal animation */
[data-reveal] {
  opacity: 0;
  transform: translateY(32px);
  transition:
    opacity 0.6s ease,
    transform 0.6s ease;
}

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

/* Scroll top */
.scroll-top {
  position: fixed;
  right: 15px;
  bottom: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: #0a3d6b;
  box-shadow: var(--shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition:
    opacity 0.3s ease,
    transform 0.3s ease,
    visibility 0.3s ease;
}

.scroll-top.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.scroll-top svg {
  width: 22px;
  height: 22px;
  fill: var(--white);
}

/* ── Responsive ── */
@media (max-width: 1199px) {
  .mobile-nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    z-index: 1002;
  }

  .navmenu {
    position: fixed;
    inset: 0;
    padding: 76px 20px 20px;
    background: rgba(0, 0, 0, 0.84);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition:
      opacity 0.25s ease,
      visibility 0.25s ease;
  }

  body.menu-open .navmenu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .navmenu ul {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 14px 0;
    border-radius: 18px;
    background: #ffffff;
    box-shadow: var(--shadow);
    overflow: hidden;
  }

  .navmenu a {
    padding: 16px 20px;
    color: #1a1444;
    font-size: 17px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  }

  .navmenu li:last-child a {
    border-bottom: 0;
  }

  .deco-left,
  .deco-right {
    width: 120px;
  }
}

@media (max-width: 767px) {
  .site-header {
    padding: 10px 0;
  }
  body.scrolled .site-header {
    padding: 8px 0;
  }
  .logo img {
    width: 100px;
  }
  .mobile-nav-toggle {
    width: 36px;
    height: 36px;
  }
  .hero {
    min-height: auto;
    padding: 90px 0;
    background-size: cover;
    background-position: center center;
  }
  .hero-content {
    padding: 20px 0 0;
  }
  .section-img {
    width: calc(100% - 40px);
  }
  .debriefing-inner {
    width: calc(100% - 40px);
  }
  .brochure-inner,
  .cta-inner {
    width: calc(100% - 40px);
  }
  .deco-left,
  .deco-right {
    width: 80px;
  }
  .cta-apply-link {
    border-radius: 8px;
  }
}

@media (max-width: 480px) {
  .deco-left,
  .deco-right {
    width: 100px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}