/* === Variables & Reset ================================================== */
:root {
  --pri-900: #020E17;
  --pri-800: #031C2B;
  --pri-700: #073456;
  --pri-500: #0A4775;
  --pri-100: #ECF3F5;
  --white: #fff;
  --radius: 1.25rem;
}
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  scroll-behavior: smooth;
}
body {
  font-family: "Pretendard", sans-serif;
  background: var(--pri-900);
  color: var(--white);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a {
  color: inherit;
  text-decoration: none;
}
a:hover,
a:focus {
  color: inherit;
  text-decoration: none;
}

/* === Header =============================================================== */
header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid var(--pri-100);
}

.nav-container {
  max-width: 1160px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  margin-right: 2.5rem;
}
.logo {
  height: 44px;
}

/* Navigation */
.nav-list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 2.5rem;
  font-size: 1.05rem;
}
.nav-item {
  position: relative;
}
.nav-button {
  all: unset;           /* font, color, padding, border 등 UI 기본값 제거 */
  font: inherit;        /* body에서 정의한 폰트 패밀리/사이즈 유지 */
  font-weight: 600;
  cursor: pointer;      /* 클릭 가능 포인터 유지 */
  color: var(--pri-700);/* 일반 상태 텍스트 색상 */
  padding: .35rem .5rem;/* hover 언더라인용 여유 공간 */
  position: relative; /* 가상 요소를 버튼 기준으로 배치 */
}
.nav-button::before {
  content: "";
  position: absolute;
  top: -10px;     /* 버튼 위로 10px 확장 */
  left: -10px;    /* 버튼 왼쪽으로 10px 확장 */
  right: -10px;   /* 버튼 오른쪽으로 10px 확장 */
  bottom: -10px;  /* 버튼 아래로 10px 확장 */
  /* 배경이나 테두리는 없으니 투명하게 보이고, 호버감지는 이 영역에서 작동 */
}
.nav-list .nav-link {
  position: relative;
  padding: .35rem .5rem;
  color: var(--pri-700);
  font-weight: 600;
  cursor: pointer;
  transition: color .25s;
}
.nav-button::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 2px;
  background: var(--pri-700);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s cubic-bezier(.4,0,.2,1);
}
.nav-list .nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: var(--pri-700);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s cubic-bezier(.4,0,.2,1);
}
.nav-button:hover,
.nav-list .nav-link:hover,
.nav-button:focus {
  outline: none;
}.nav-list .nav-link:focus {
  color: var(--pri-500);
}
.nav-button:hover::after,
.nav-list .nav-link:hover::after,
.nav-button:focus::after {
  transform: scaleX(1);
}
.nav-list .nav-link:focus::after {
  transform: scaleX(1);
}

/* Dropdown */
.dropdown {
  position: relative;
}
.sub-menu {
  list-style: none;
  position: absolute;
  top: 120%;
  left: 0;
  min-width: 170px;
  padding: .5rem 0;
  background: rgba(255,255,255,0.96);
  color: var(--pri-700);
  border-radius: .5rem;
  box-shadow: 0 8px 20px rgba(0,0,0,.15);
  backdrop-filter: blur(6px);
  opacity: 0;
  transform: translateY(-10px);
  transition: opacity .25s, transform .25s;
  pointer-events: none;
}
.dropdown:hover .sub-menu,
.dropdown.open .sub-menu {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.sub-menu li a {
  display: block;
  padding: .55rem 1rem;
  font-weight: 500;
  color: inherit;
}
.sub-menu li a:hover {
  background: var(--pri-100);
}
@media (hover: none) {
  .dropdown > .nav-button:active + .sub-menu,
  .dropdown.open .sub-menu {
    opacity: 1;
    transform: translateY(0);
  }
}

/* === Hero =============================================================== */
.hero {
  width: 100vw;
  margin-left: calc(-50vw + 50%);
  max-width: none;
  position: relative;
  padding: 6rem 1rem 5rem;
  text-align: center;
  color: var(--white);
  background: linear-gradient(135deg, var(--pri-700) 0%, var(--pri-800) 100%);
  border-bottom-left-radius: var(--radius);
  border-bottom-right-radius: var(--radius);
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  box-shadow: 0 12px 32px rgba(0, 0, 0, .25);
  border-radius: inherit;
}
.hero h1 {
  font-size: clamp(2.4rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: -1px;
}
.hero p {
  font-size: 1.1rem;
  margin-top: 1.2rem;
  color: var(--pri-100);
}
.video-hero {
  padding: 0;
  height: 80vh;
  min-height: 480px;
}
.video-hero video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.video-hero .overlay {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  background: rgba(0, 0, 0, .45);
}
.video-hero h1 {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
}
.video-hero p {
  margin: .8rem 0 2rem;
  font-size: 1.1rem;
  color: var(--pri-100);
}

/* === Section & Footer =================================================== */
section {
  max-width: 1080px;
  margin: 4.5rem auto;
  padding: 0 1.5rem;
}
.content-box {
  background: var(--pri-800);
  border-radius: var(--radius);
  padding: 2rem;
  margin: 4rem auto;
}
footer {
  border-top: 1px solid var(--pri-800);
  background: rgba(3,12,20,.85);
  font-size: .9rem;
  color: var(--gray-200);
  text-align: center;
  padding: 2.7rem 1rem 3rem;
}
footer a:hover,
footer a:focus {
  color: var(--pri-100);
}

/* === Buttons =============================================================== */
.btn {
  position: relative;
  overflow: hidden;
  display: inline-block;
  padding: .65rem 1.3rem;
  border-radius: 999px;
  font-weight: 600;
  background: var(--pri-700);
  color: var(--white);
  transition: background .25s;
}
.btn:hover,
.btn:focus {
  background: var(--pri-500);
}
.mail-btn {
  margin-top: 1.5rem;
}


/* === Responsive Adjustments ============================================= */
@media (max-width: 768px) {
  /* 로고 크기 축소 */
  .logo { height: 32px; }
  /* 내비게이션 글자 및 간격 조정 */
  .nav-list { gap: 1rem; font-size: 0.95rem; }
  /* 버튼 및 링크 패딩/폰트 크기 축소 */
  .nav-button,
  .nav-link { padding: 0.25rem 0.5rem; font-size: 0.95rem; }
  /* 로고 아래로 버튼 그룹 이동 */
  .nav-container { flex-direction: column; align-items: flex-start; }
  .nav-list { margin-top: 0.5rem; }
}

/* === Responsive Adjustments ========================================================= */
@media (max-width: 768px) {
  /* Reduce logo size */
  .logo {
    height: 32px;
  }
  /* Adjust navigation font and spacing */
  .nav-list {
    gap: 1rem;
    font-size: 0.95rem;
  }
  /* Reduce button/link padding and font size */
  .nav-button,
  .nav-link {
    padding: 0.25rem 0.5rem;
    font-size: 0.95rem;
  }
}

.model-frame {
  width: 100%;
  /* height는 내용에 맞춰 JS로 조절 중이니 그대로 두면 되고 */
}