/* ========== HEADER / NAVIGATION ========== */
      header {
        position: fixed;
        top: 0;
        width: 100%;
        z-index: 1000;
        transition: all 0.3s ease;
        background: transparent;
    }

    header.scrolled {
        background: rgba(255, 255, 255, 0.9);
        backdrop-filter: blur(12px);
        box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
        border-bottom: 1px solid #dbeafe;
    }

    .header-inner {
        max-width: 1280px;
        margin: 0 auto;
        padding: 0 16px;
        display: flex;
        justify-content: space-between;
        align-items: center;
        height: 80px;
    }

    /* 로고 */
    .logo {
        display: flex;
        align-items: center;
        margin-left: -100px;
    }

    .logo-image {
        height: 100px;
        transition: transform 0.3s ease;
    }

    .logo:hover .logo-image {
        transform: scale(1.02);
    }

    /* 네비게이션 */
    nav {
        display: flex;
        align-items: center;
        gap: 32px;
    }

    nav > a {
        position: relative;
        color: #374151;
        text-decoration: none;
        font-weight: 500;
        transition: color 0.3s ease;
        display: flex;
        align-items: center;
        gap: 4px;
    }

    nav > a:hover,
    nav > a.active {
        color: #1e3a8a;
    }

    /* 밑줄 애니메이션 */
    nav > a::after {
        content: '';
        position: absolute;
        bottom: -4px;
        left: 0;
        width: 0;
        height: 2px;
        background: linear-gradient(to right, #1e3a8a, #1e40af);
        transition: width 0.3s ease;
    }

    nav > a:hover::after,
    nav > a.active::after {
        width: 100%;
    }

    /* 드롭다운 컨테이너 */
    .nav-item-with-dropdown {
        position: relative;
    }

    .nav-link {
        display: flex;
        align-items: center;
        gap: 4px;
        cursor: pointer;
    }

    .chevron-icon {
        width: 16px;
        height: 16px;
        transition: transform 0.3s ease;
    }

    .nav-item-with-dropdown:hover .chevron-icon {
        transform: rotate(180deg);
    }

    /* 드롭다운 메뉴 */
    .dropdown-menu {
        position: absolute;
        top: calc(100% + 8px);
        left: 0;
        width: 192px;
        background: white;
        border: 1px solid #dbeafe;
        border-radius: 8px;
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        padding: 8px 0;
        opacity: 0;
        visibility: hidden;
        transform: translateY(-10px);
        transition: all 0.3s ease;
    }

    .nav-item-with-dropdown:hover .dropdown-menu {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }

    .dropdown-menu a {
        display: block;
        padding: 8px 16px;
        color: #374151;
        text-decoration: none;
        transition: all 0.2s ease;
    }

    .dropdown-menu a:hover {
        background: #eff6ff;
        color: #1e3a8a;
    }

    /* 모바일 메뉴 버튼 */
    .mobile-menu-button {
        display: none;
        background: none;
        border: none;
        cursor: pointer;
        padding: 8px;
    }

    .mobile-menu-button svg {
        width: 24px;
        height: 24px;
        color: #1e3a8a;
    }

    /* 모바일 메뉴 */
    .mobile-menu {
        display: none;
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(12px);
        border-top: 1px solid #dbeafe;
        padding: 16px;
    }

    .mobile-menu.active {
        display: block;
    }

    .mobile-menu a {
        display: block;
        padding: 12px 16px;
        color: #374151;
        text-decoration: none;
        border-radius: 8px;
        transition: all 0.2s ease;
        margin-bottom: 4px;
    }

    .mobile-menu a:hover,
    .mobile-menu a.active {
        background: #eff6ff;
        color: #1e3a8a;
    }

    .mobile-submenu {
        padding-left: 16px;
        margin-top: 4px;
    }

    .mobile-submenu a {
        font-size: 0.875rem;
        color: #6b7280;
    }


    * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
    }

 body {
        font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
        overflow-x: hidden;
        background: white;
    }


    /* ========== 컨텐츠 영역 ========== */
    .content {
        position: relative;
        z-index: 10;
    }

    /* ========== HERO SECTION ========== */
    #home {
        min-height: 100vh;
        padding-top: 20px;
        position: relative;
        display: flex;
        align-items: center;
    }

    .container {
        max-width: 1280px;
        margin: 0 auto;
        padding: 80px 16px;
        width: 100%;
    }

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

    .main-title {
        color: #1e3a8a;
        font-size: 3.25rem;
        font-weight: bold;
        margin-bottom: 24px;
        animation: fadeInUp 0.8s ease-out;
    }

    .subtitle {
        background: linear-gradient(to right, #1e3a8a, #1e40af, #1d4ed8);
        -webkit-background-clip: text;
        -webkit-text-fill-color: transparent;
        background-clip: text;
        font-size: rem;
        margin-bottom: 48px;
        animation: fadeInUp 0.8s ease-out 0.2s both;
    }

    /* ========== 슬라이더 ========== */
    .slider-wrapper {
        max-width: 700px;
        margin: 0 auto;
        animation: fadeInUp 0.8s ease-out 0.4s both;
    }

    .slider-container {
        position: relative;
        overflow: hidden;
    }

    .slider-track {
        position: relative;
        border-radius: 16px;
        overflow: hidden;
        box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    }

    .slide {
        display: none;
        opacity: 0;
        transition: opacity 0.3s ease-in-out;
    }

    .slide.active {
        display: block;
        opacity: 1;
        animation: slideIn 0.3s ease-out;
    }

    .slide-image {
        width: 100%;
        aspect-ratio: 16/9;
        object-fit: cover;
    }

    .slide-title {
        background: rgba(255, 255, 255, 0.9);
        backdrop-filter: blur(8px);
        padding: 8px;
        border-top: 1px solid rgba(191, 219, 254, 0.5);
    }

    .slide-title p {
        color: #1e3a8a;
        font-size: 1rem;
        font-weight: 600;
        text-align: center;
    }

    /* 네비게이션 버튼 */
    .nav-button {
        position: absolute;
        top: 50%;
        transform: translateY(-50%);
        background: rgba(255, 255, 255, 0.8);
        border: 1px solid rgba(255, 255, 255, 0.5);
        border-radius: 8px;
        width: 40px;
        height: 40px;
        display: flex;
        align-items: center;
        justify-content: center;
        cursor: pointer;
        transition: all 0.2s;
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        z-index: 10;
    }

    .nav-button:hover {
        background: white;
        border-color: #2563eb;
    }

    .nav-button.prev {
        left: 16px;
    }

    .nav-button.next {
        right: 16px;
    }

    .nav-button svg {
        width: 20px;
        height: 20px;
        color: #1e3a8a;
    }

    /* 도트 인디케이터 */
    .dots-container {
        display: flex;
        justify-content: center;
        gap: 8px;
        margin-top: 16px;
    }

    .dot {
        height: 8px;
        width: 8px;
        border-radius: 9999px;
        background: rgba(30, 58, 138, 0.3);
        cursor: pointer;
        transition: all 0.3s;
        border: none;
        padding: 0;
    }

    .dot:hover {
        background: rgba(30, 58, 138, 0.5);
    }

    .dot.active {
        width: 32px;
        background: linear-gradient(to right, #1e3a8a, #1e40af);
        box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    }

    /* ========== RESEARCH AREAS SECTION ========== */
    #research-areas {
        padding: 80px 0;
    }

    .section-header {
        text-align: center;
        margin-bottom: 64px;
        animation: fadeInUp 0.6s ease-out;
    }

    .section-title {
        font-size: 2.25rem;
        color: #1e3a8a;
        margin-bottom: 16px;
        font-weight: bold;
    }

    .section-description {
        color: #4b5563;
        max-width: 672px;
        margin: 0 auto;
        font-size: 1.125rem;
        line-height: 1.75;
    }

    /* 연구 영역 그리드 */
    .research-grid {
        display: grid;
        grid-template-columns: repeat(1, 1fr);
        gap: 32px;
        max-width: 1280px;
        margin: 0 auto;
        padding: 0 16px;
    }

    @media (min-width: 768px) {
        .research-grid {
            grid-template-columns: repeat(2, 1fr);
        }
    }

    @media (min-width: 1024px) {
        .research-grid {
            grid-template-columns: repeat(4, 1fr);
        }
    }

    .research-card {
        background: rgba(255, 255, 255, 0.7);
        backdrop-filter: blur(8px);
        border-radius: 16px;
        padding: 32px;
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        border: 2px solid rgba(255, 255, 255, 0.5);
        transition: all 0.3s ease;
        min-height: 280px;
        display: flex;
        flex-direction: column;
        align-items: center;
        text-align: center;
        animation: fadeInUp 0.5s ease-out both;
    }

    .research-card:nth-child(1) { animation-delay: 0s; }
    .research-card:nth-child(2) { animation-delay: 0.1s; }
    .research-card:nth-child(3) { animation-delay: 0.2s; }
    .research-card:nth-child(4) { animation-delay: 0.3s; }

    .research-card:hover {
        box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
        border-color: #bfdbfe;
        transform: translateY(-4px);
    }

    .research-icon {
        width: 64px;
        height: 64px;
        background: linear-gradient(to bottom right, #1e3a8a, #1d4ed8);
        border-radius: 12px;
        display: flex;
        align-items: center;
        justify-content: center;
        margin-bottom: 24px;
        box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
        transition: transform 0.3s ease;
    }

    .research-card:hover .research-icon {
        transform: scale(1.1);
    }

    .research-icon svg {
        width: 32px;
        height: 32px;
        color: white;
    }

    .research-title {
        font-size: 1.25rem;
        color: #1e3a8a;
        margin-bottom: 8px;
        font-weight: 600;
    }

    .research-description {
        color: #374151;
        margin-bottom: 12px;
        font-weight: 500;
    }

    .research-detail {
        color: #4b5563;
        font-size: 0.875rem;
        line-height: 1.5;
        white-space: pre-line;
    }

    /* ========== 배경 래퍼 ========== */
    .page-wrapper {
        position: relative;
        background: linear-gradient(to bottom right, #eff6ff, #dbeafe, #eff6ff);
        overflow: hidden;
    }

    /* ========== 움직이는 파란 동그라미 배경 ========== */
    .background-decoration {
        position: absolute;
        inset: 0;
        overflow: hidden;
        pointer-events: none;
    }
    .blob {
        position: absolute;
        border-radius: 50%;
        mix-blend-mode: multiply;
        filter: blur(64px);
        opacity: 0.2;
        animation: blob 7s infinite;
    }

    .blob-1 {
        top: 80px;
        right: 25%;
        width: 256px;
        height: 256px;
        background-color: #bfdbfe;
    }

    .blob-2 {
        top: 160px;
        left: 33.333%;
        width: 288px;
        height: 288px;
        background-color: #93c5fd;
        animation-delay: 4s;
    }

    .blob-3 {
        top: -160px;
        right: -160px;
        width: 320px;
        height: 320px;
        background-color: #93c5fd;
    }

    .blob-4 {
        bottom: -160px;
        left: -160px;
        width: 320px;
        height: 320px;
        background-color: #60a5fa;
        animation-delay: 2s;
    }

    .blob-5 {
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        width: 320px;
        height: 320px;
        background-color: #3b82f6;
        animation-delay: 4s;
    }

    .blob-6 {
        bottom: 25%;
        right: 33.333%;
        width: 256px;
        height: 256px;
        background-color: #60a5fa;
        animation-delay: 2s;
    }

    @keyframes blob {
        0% {
            transform: translate(0px, 0px) scale(1);
        }
        33% {
            transform: translate(30px, -50px) scale(1.1);
        }
        66% {
            transform: translate(-20px, 20px) scale(0.9);
        }
        100% {
            transform: translate(0px, 0px) scale(1);
        }
    }

   
    /* ========== 애니메이션 ========== */
    @keyframes fadeInUp {
        from {
            opacity: 0;
            transform: translateY(20px);
        }
        to {
            opacity: 1;
            transform: translateY(0);
        }
    }

    @keyframes slideIn {
        from {
            opacity: 0;
            transform: translateX(100px);
        }
        to {
            opacity: 1;
            transform: translateX(0);
        }
    }

    /* ========== 반응형 ========== */
    @media (max-width: 768px) {
        /* 헤더 모바일 */
        .logo {
            margin-left: 0;
        }
        
        .logo-image {
            height: 200px;
        }

        nav {
            display: none;
        }

        .mobile-menu-button {
            display: block;
        }

        /* 컨텐츠 모바일 */
        .main-title {
            font-size: 2rem;
        }
        .subtitle {
            font-size: 1.5rem;
        }
        .section-title {
            font-size: 1.875rem;
        }
        .section-description {
            font-size: 1rem;
        }
        .slide-title p {
            font-size: 0.875rem;
        }
        .blob {
            filter: blur(48px);
        }
        .research-card {
            min-height: auto;
        }
    }

    @media (max-width: 640px) {
        .main-title {
            font-size: 1.5rem;
        }
        .subtitle {
            font-size: 1.25rem;
        }
        .container {
            padding: 40px 16px;
        }
        #research-areas {
            padding: 40px 0;
        }
        .section-header {
            margin-bottom: 32px;
        }
    }
    

@media (max-width: 768px) {
    /* 헤더 높이도 모바일에서는 조금 줄이는 것이 자연스럽습니다 (선택사항) */
    .header-inner {
        height: 60px; /* 기존 80px -> 60px */
        padding: 0 12px;
    }

    /* 로고 컨테이너의 이상한 여백 제거 */
    .logo {
        margin-left: 0; /* PC용 -100px 여백을 모바일에서는 0으로 초기화 */
    }

    /* 로고 이미지 크기 축소 */
    .logo-image {
        height: 40px; /* PC 100px -> 모바일 40px (원하는 크기로 조절하세요) */
        width: auto;  /* 비율 유지 */
    }

    /* 햄버거 메뉴 버튼 위치 미세 조정 (필요시) */
    .mobile-menu-button {
        padding: 4px;
    }
}