* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: -apple-system, BlinkMacSystemFont, "Pretendard", "Malgun Gothic", sans-serif;
}

body {
  background-color: #1a2e2b;
  min-height: 100vh;
  overflow-x: hidden;
}

/* 1. 상단 네비게이션 헤더 */
.header-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100px;
  padding: 0 60px 10px 60px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 1000;
}

.header-nav::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    180deg, 
    rgba(31, 64, 55, 0.55) 0%, 
    rgba(41, 87, 76, 0.40) 70%, 
    rgba(56, 115, 100, 0.30) 100%
  );
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  clip-path: ellipse(110% 100% at 50% 0%);
  z-index: -1;
  transition: background 0.4s ease, backdrop-filter 0.4s ease, box-shadow 0.4s ease;
}

.header-nav.scrolled::after {
  background: linear-gradient(
    180deg, 
    rgba(23, 51, 44, 0.88) 0%, 
    rgba(31, 64, 55, 0.82) 100%
  );
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.25);
}

/* 2. 로고 */
.logo {
  font-size: 24px;
  font-weight: 800;
  color: #ffffff;
  text-decoration: none;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.55);
  letter-spacing: -0.5px;
  white-space: nowrap;
}

/* 3. 메뉴 리스트 & 2차 드롭다운 */
.nav-menu {
  display: flex;
  gap: 28px;
  list-style: none;
  align-items: center;
}

.nav-menu > li {
  position: relative;
  padding: 10px 0;
}

.nav-menu > li > a {
  text-decoration: none;
  color: #ffffff;
  font-weight: 700;
  font-size: 16px;
  text-shadow: 0 2px 6px rgba(0, 0, 0, 0.5);
  transition: opacity 0.2s, color 0.2s;
  letter-spacing: -0.3px;
  white-space: nowrap;
}

.nav-menu > li:hover > a {
  color: #64ffda;
  text-shadow: 0 3px 12px rgba(100, 255, 218, 0.6);
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(10px);
  background: rgba(20, 45, 38, 0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  min-width: 170px;
  border-radius: 12px;
  padding: 10px 0;
  list-style: none;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
  border: 1px solid rgba(255, 255, 255, 0.15);
  opacity: 0;
  visibility: hidden;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 2000;
}

.nav-menu > li:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.dropdown-menu li a {
  display: block;
  padding: 9px 20px;
  color: #e2edea;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.2s, color 0.2s, padding-left 0.2s;
  white-space: nowrap;
}

.dropdown-menu li a:hover {
  background: rgba(100, 255, 218, 0.15);
  color: #64ffda;
  padding-left: 24px;
}

.user-icon {
  width: 38px;
  height: 38px;
  border: 2px solid rgba(255, 255, 255, 0.85);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  filter: drop-shadow(0 2px 6px rgba(0, 0, 0, 0.45));
  transition: border-color 0.2s;
}

.user-icon:hover {
  border-color: #64ffda;
}

/* 4. 배경 롤링 슬라이더 */
.hero-slider-wrap {
  position: relative;
  width: 100%;
  height: 100vh;
  overflow: hidden;
}

.slide-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center center;
  opacity: 0;
  transform: scale(1.05);
  transition: opacity 1.2s ease-in-out, transform 6s ease-out;
  z-index: 1;
}

.slide-bg.active {
  opacity: 1;
  transform: scale(1);
  z-index: 2;
}

.hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    to bottom,
    rgba(20, 45, 38, 0.35) 0%,
    rgba(20, 45, 38, 0.50) 50%,
    rgba(15, 35, 30, 0.85) 100%
  );
  z-index: 3;
  pointer-events: none;
}

/* 5. 메인 히어로 콘텐츠: 메인 문구가 화면 정중앙(50%)에 오도록 배치 */
.hero-content {
  position: absolute;
  top: calc(50% + 50px);
  left: 50%;
  transform: translate(-50%, -50%);
  width: 100%;
  max-width: 1200px;
  padding: 0 20px;
  text-align: center;
  color: #ffffff;
  z-index: 4;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-subtitle {
  font-size: 21px;
  font-weight: 500;
  opacity: 0.95;
  margin-bottom: 12px;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.7);
  letter-spacing: -0.3px;
}

.hero-title {
  font-size: 52px; /* 문구 크기를 더 시원하게 키워 중심감 확보 */
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 34px; /* 문구와 버튼 사이 여백 */
  text-shadow: 0 4px 16px rgba(0, 0, 0, 0.75);
  letter-spacing: -1.2px;
}

/* 6. CTA 버튼: 라인/아이콘 제거 및 메인 딥 에메랄드 톤 적용 */
.hero-cta-wrap {
  display: flex;
  justify-content: center;
  gap: 18px;
}

.hero-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 170px;
  padding: 16px 36px;
  border-radius: 50px;
  font-size: 17px;
  font-weight: 700;
  text-decoration: none;
  border: none; /* 라인 완전 제거 */
  outline: none;
  letter-spacing: -0.3px;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  cursor: pointer;
}

/* 버튼 1: 메인 딥 에메랄드 컬러 (학술회의) */
.hero-btn.primary-btn {
  background: linear-gradient(135deg, #1f453c 0%, #29574c 100%);
  color: #ffffff;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.35);
}

.hero-btn.primary-btn:hover {
  transform: translateY(-3px) scale(1.03);
  background: linear-gradient(135deg, #27594d 0%, #356e61 100%);
  box-shadow: 0 14px 30px rgba(0, 0, 0, 0.45);
}

/* 버튼 2: 은은한 반투명 글래스 (논문보기) - 보더 없음 */
.hero-btn.glass-btn {
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  color: #ffffff;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.25);
}

.hero-btn.glass-btn:hover {
  transform: translateY(-3px) scale(1.03);
  background: rgba(255, 255, 255, 0.25);
  box-shadow: 0 14px 30px rgba(0, 0, 0, 0.35);
}

/* 슬라이드 인디케이터 점 */
.slider-dots {
  position: absolute;
  bottom: 35px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 5;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.4);
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.7);
  transition: all 0.3s ease;
}

.dot.active {
  width: 28px;
  border-radius: 6px;
  background-color: #64ffda;
  border-color: #64ffda;
  box-shadow: 0 0 10px rgba(100, 255, 218, 0.6);
}

/* 7. 푸터 */
.site-footer {
  background-color: #122420;
  color: #8fa8a2;
  padding: 40px 20px;
  text-align: center;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  list-style: none;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.footer-links a {
  color: #b0c9c3;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: #64ffda;
}

.copyright {
  font-size: 13px;
  color: #6b857f;
}