/* 기본 스타일 리셋 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 기본 폰트 및 색상 - 의료/연구 테마 */
:root {
    --primary-color: #2c5aa0;
    --secondary-color: #4a90e2;
    --accent-color: #e74c3c;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --text-color: #2c3e50;
    --light-text: #7f8c8d;
    --background: #ffffff;
    --light-background: #f8f9fa;
    --medical-blue: #e3f2fd;
    --border-color: #ecf0f1;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --transition: all 0.3s ease;
}

body {
    font-family: 'Noto Sans KR', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background);
}

/* 헤더 스타일 */
.header {
    background: var(--background);
    box-shadow: var(--shadow);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 90px;
    flex-wrap: wrap;
}

.logo h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo .title {
    font-size: 0.9rem;
    color: var(--light-text);
    margin-top: -5px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-menu a:hover {
    color: var(--secondary-color);
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--secondary-color);
    transition: var(--transition);
}

.nav-menu a:hover::after {
    width: 100%;
}

/* 언어 선택기 스타일 */
.language-selector {
    display: flex;
    gap: 5px;
    margin-right: 20px;
    position: relative;
    z-index: 1001;
}

.lang-btn {
    padding: 8px 16px;
    border: 2px solid var(--border-color);
    background: transparent;
    color: var(--text-color);
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: 'Noto Sans KR', sans-serif;
}

.lang-btn:hover {
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}

.lang-btn.active {
    background: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.lang-btn.active:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    margin: 3px 0;
    transition: var(--transition);
}

/* 메인 컨텐츠 */
main {
    margin-top: 90px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 히어로 섹션 - 의료 테마 */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 100px 0;
    min-height: 80vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="white" opacity="0.1"/><circle cx="75" cy="75" r="1" fill="white" opacity="0.1"/><circle cx="50" cy="10" r="0.5" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-text h2 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 20px;
    font-family: 'Noto Serif KR', serif;
}

.hero-text .subtitle {
    font-size: 1.5rem;
    margin-bottom: 20px;
    opacity: 0.9;
}

.hero-text .description {
    font-size: 1.1rem;
    margin-bottom: 30px;
    opacity: 0.8;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 20px;
}

.cta-button {
    padding: 15px 30px;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
}

.cta-button.primary {
    background: var(--accent-color);
    color: white;
}

.cta-button.primary:hover {
    background: #c0392b;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(231, 76, 60, 0.4);
}

.cta-button.secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.cta-button.secondary:hover {
    background: white;
    color: var(--primary-color);
    transform: translateY(-2px);
}

.profile-placeholder {
    width: 300px;
    height: 300px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 5rem;
    color: rgba(255,255,255,0.3);
    margin: 0 auto;
    border: 3px solid rgba(255,255,255,0.2);
}

/* 섹션 공통 스타일 */
section {
    padding: 80px 0;
}

section h2 {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 50px;
    color: var(--primary-color);
    font-family: 'Noto Serif KR', serif;
    position: relative;
}

section h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
    border-radius: 2px;
}

/* 소개 섹션 */
.about {
    background: var(--light-background);
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 50px;
}

.about-text h3 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.about-text h3::before {
    content: '🔬';
    font-size: 1.2rem;
}

.about-text p {
    margin-bottom: 20px;
    line-height: 1.8;
    color: var(--light-text);
}

.timeline {
    list-style: none;
    margin-top: 30px;
}

.timeline li {
    display: flex;
    margin-bottom: 20px;
    align-items: center;
}

.timeline .year {
    background: var(--secondary-color);
    color: white;
    padding: 8px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    margin-right: 20px;
    min-width: 100px;
    text-align: center;
}

.timeline .content {
    color: var(--text-color);
    font-weight: 500;
}

/* 기술 스타일 */
.skills-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.skill-item {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.skill-name {
    font-weight: 600;
    color: var(--primary-color);
}

.skill-bar {
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.skill-level {
    height: 100%;
    background: linear-gradient(90deg, var(--secondary-color), var(--success-color));
    border-radius: 4px;
    transition: width 1s ease;
}

/* 제품 섹션 스타일 */
.products {
    padding: 80px 0;
    background: var(--background);
}

.section-subtitle {
    text-align: center;
    color: var(--light-text);
    font-size: 1.1rem;
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.product-card {
    background: var(--background);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.product-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
    position: relative;
}

.product-card:nth-child(1) .product-icon {
    background: linear-gradient(135deg, #fdf900, #ffd700);
    color: #222;
}

.product-card:nth-child(2) .product-icon {
    background: linear-gradient(135deg, #00d4aa, #00a085);
}

.product-card:nth-child(3) .product-icon {
    background: linear-gradient(135deg, #ff6f00, #e65100);
}

.product-card:nth-child(4) .product-icon {
    background: linear-gradient(135deg, #8e44ad, #6a1b9a);
}

.product-card h3 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.product-subtitle {
    font-size: 0.9rem;
    color: var(--light-text);
    margin-bottom: 1rem;
    font-weight: 500;
}

.product-description {
    color: var(--text-color);
    line-height: 1.6;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.product-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.product-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    font-size: 0.9rem;
}

.product-link.primary {
    background: var(--primary-color);
    color: white;
}

.product-link.primary:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

.product-link.secondary {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.product-link.secondary:hover {
    background: var(--primary-color);
    color: white;
}

/* 연구 섹션 - 파이프라인 포함 */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 30px;
}

.research-card {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.research-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
}

.research-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
}

.research-icon {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 20px;
    text-align: center;
}

.research-card h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--primary-color);
}

.research-card p {
    color: var(--light-text);
    margin-bottom: 20px;
    line-height: 1.6;
}

/* 파이프라인 스타일 */
.pipeline-info {
    background: var(--medical-blue);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    border-left: 4px solid var(--secondary-color);
}

.pipeline-info h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.pipeline-info h4::before {
    content: '📋';
    font-size: 1rem;
}

.pipeline-list {
    list-style: none;
}

.pipeline-list li {
    margin-bottom: 10px;
    padding: 8px 0;
    border-bottom: 1px solid rgba(74, 144, 226, 0.2);
}

.pipeline-list li:last-child {
    border-bottom: none;
}

.pipeline-list .stage {
    background: var(--secondary-color);
    color: white;
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-right: 10px;
}

.research-tags {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.tag {
    background: var(--light-background);
    color: var(--primary-color);
    padding: 5px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
}

/* 논문 섹션 */
.publications {
    background: var(--light-background);
}

.publications-list {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.publication-item {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    display: flex;
    gap: 30px;
    align-items: flex-start;
    transition: var(--transition);
}

.publication-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
}

.pub-year {
    background: var(--accent-color);
    color: white;
    padding: 10px 20px;
    border-radius: 25px;
    font-weight: 700;
    font-size: 1.1rem;
    min-width: 80px;
    text-align: center;
}

.pub-content h3 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.pub-authors {
    color: var(--light-text);
    margin-bottom: 5px;
}

.pub-journal {
    color: var(--light-text);
    margin-bottom: 15px;
    font-style: italic;
}

.pub-links {
    display: flex;
    gap: 15px;
}

.pub-link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 5px;
}

.pub-link:hover {
    color: var(--primary-color);
}

/* 연락처 섹션 */
.contact {
    background: var(--light-background);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
}

.contact-info h3, .social-links h3 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
    color: var(--text-color);
    padding: 10px;
    border-radius: 8px;
    transition: var(--transition);
}

.contact-item:hover {
    background: white;
    box-shadow: var(--shadow);
}

.contact-item i {
    color: var(--secondary-color);
    font-size: 1.2rem;
    width: 20px;
}

.social-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.social-link {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    padding: 15px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.social-link:hover {
    background: var(--secondary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

/* 푸터 */
.footer {
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 30px 0;
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .language-selector {
        margin-right: 10px;
    }
    
    .lang-btn {
        padding: 6px 12px;
        font-size: 0.8rem;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-text h2 {
        font-size: 2rem;
    }
    
    .about-content {
        grid-template-columns: 1fr;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .research-grid {
        grid-template-columns: 1fr;
    }
    
    .publication-item {
        flex-direction: column;
        gap: 20px;
    }
    
    .pub-year {
        align-self: flex-start;
    }
    
    .social-grid {
        grid-template-columns: 1fr;
    }
    
    .pipeline-list .stage {
        display: block;
        margin-bottom: 5px;
        width: fit-content;
    }

    .filter-controls {
        flex-direction: column;
        gap: 20px;
        align-items: stretch;
    }
    
    .filter-select {
        min-width: auto;
        width: 100%;
    }
    
    .publications-header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .upload-area {
        padding: 30px 20px;
    }
    
    .upload-content i {
        font-size: 2.5rem;
    }
    
    .upload-content h3 {
        font-size: 1.3rem;
    }
    
    .products-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .product-card {
        padding: 1.5rem;
    }
    
    .product-icon {
        width: 60px;
        height: 60px;
        font-size: 1.5rem;
    }
    
    .product-card h3 {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .nav-container {
        height: 80px;
    }
    
    .hero {
        padding: 60px 0;
    }
    
    .hero-text h2 {
        font-size: 1.8rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .cta-button {
        width: 100%;
        max-width: 250px;
    }
    
    .research-card {
        padding: 20px;
    }
    
    .pipeline-info {
        padding: 15px;
    }
    
    .language-selector {
        flex-direction: column;
        gap: 3px;
    }
    
    .lang-btn {
        padding: 4px 8px;
        font-size: 0.7rem;
    }

    .upload-area {
        padding: 25px 15px;
    }
    
    .filter-section {
        padding: 20px;
    }
    
    .uploaded-publications {
        padding: 20px;
    }
    
    .publication-card {
        padding: 15px;
    }
    
    .pub-card-header {
        flex-direction: column;
        gap: 10px;
        align-items: flex-start;
    }
    
    .product-card {
        padding: 1rem;
    }
    
    .product-icon {
        width: 50px;
        height: 50px;
        font-size: 1.2rem;
    }
    
    .product-card h3 {
        font-size: 1.3rem;
    }
    
    .product-description {
        font-size: 0.9rem;
    }
    
    .product-link {
        padding: 0.6rem 1.2rem;
        font-size: 0.8rem;
    }
}