/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #64748b;
    --accent-color: #0ea5e9;
    --text-color: #1e293b;
    --text-light: #64748b;
    --bg-color: #ffffff;
    --bg-alt: #f8fafc;
    --border-color: #e2e8f0;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --card-shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --transition: all 0.3s ease;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Playfair Display', Georgia, serif;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--bg-color);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--primary-dark);
}

img {
    max-width: 100%;
    height: auto;
}

/* Container */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}

.navbar.scrolled {
    border-bottom-color: var(--border-color);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-menu a {
    color: var(--text-color);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    position: relative;
}

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

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

.nav-cv {
    background: var(--primary-color) !important;
    color: white !important;
    padding: 0.5rem 1rem !important;
    border-radius: 6px;
}

.nav-cv::after {
    display: none !important;
}

.nav-cv:hover {
    background: var(--primary-dark) !important;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background: var(--text-color);
    transition: var(--transition);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, #f8fafc 0%, #e0f2fe 100%);
}

.hero-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-image img {
    width: 100%;
    border-radius: 20px;
    box-shadow: var(--card-shadow-hover);
}

.hero-content h1 {
    font-family: var(--font-serif);
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.hero-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.hero-affiliation {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
}

.hero-affiliation a {
    color: var(--secondary-color);
}

.hero-affiliation a:hover {
    color: var(--primary-color);
}

.hero-description {
    font-size: 1.15rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    max-width: 500px;
}

.hero-links {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.4);
}

.btn-secondary {
    background: white;
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateY(-2px);
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: white;
    color: var(--text-light);
    font-size: 1.1rem;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-3px);
}

/* Sections */
.section {
    padding: 5rem 0;
}

.section-alt {
    background: var(--bg-alt);
}

.section-title {
    font-family: var(--font-serif);
    font-size: 2.25rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--primary-color);
    margin: 1rem auto 0;
    border-radius: 2px;
}

/* About Section */
.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-content p {
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
}

.about-content p:last-child {
    margin-bottom: 0;
}

/* Research Section */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.research-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    text-align: center;
}

.research-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-shadow-hover);
}

.research-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto 1.5rem;
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.research-icon i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

.research-card h3 {
    font-size: 1.2rem;
    margin-bottom: 0.75rem;
    color: var(--text-color);
}

.research-card p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Publications Section */
.publications-list {
    max-width: 800px;
    margin: 0 auto;
}

.publication {
    background: white;
    padding: 1.75rem;
    border-radius: 12px;
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--primary-color);
    transition: var(--transition);
    box-shadow: var(--card-shadow);
}

.publication:hover {
    transform: translateX(5px);
    box-shadow: var(--card-shadow);
}

.pub-badge {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.pub-title {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.pub-title a {
    color: var(--text-color);
}

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

.pub-authors {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 0.25rem;
}

.pub-venue {
    color: var(--secondary-color);
    font-size: 0.9rem;
    font-style: italic;
}

/* Education Timeline */
.timeline {
    max-width: 700px;
    margin: 0 auto;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 10px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-color);
}

.timeline-item {
    position: relative;
    padding-left: 50px;
    margin-bottom: 2.5rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: 0;
    top: 5px;
    width: 22px;
    height: 22px;
    background: white;
    border: 3px solid var(--primary-color);
    border-radius: 50%;
}

.timeline-content {
    background: white;
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
}

.timeline-date {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.timeline-content h3 {
    font-size: 1.2rem;
    margin-bottom: 0.25rem;
}

.timeline-institution {
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 0.75rem;
}

.timeline-content p:last-child {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* Awards Section */
.awards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.award-card {
    background: var(--bg-alt);
    padding: 1.5rem;
    border-radius: 12px;
    text-align: center;
    transition: var(--transition);
}

.award-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--card-shadow);
}

.award-year {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.award-card h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.award-card p {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
}

.award-org {
    color: var(--secondary-color);
    font-size: 0.85rem;
    font-weight: 500;
}

/* Projects Accordion */
.projects-list {
    max-width: 900px;
    margin: 0 auto;
}

.project-item {
    background: var(--bg-alt);
    border-radius: 12px;
    margin-bottom: 1rem;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.project-item:hover {
    border-color: var(--primary-color);
}

.project-item.active {
    border-color: var(--primary-color);
    box-shadow: var(--card-shadow);
}

.project-header {
    width: 100%;
    padding: 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-align: left;
    gap: 1rem;
}

.project-header:hover {
    background: rgba(37, 99, 235, 0.03);
}

.project-header-content {
    flex: 1;
}

.project-header-content h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 0.25rem;
}

.project-meta {
    font-size: 0.9rem;
    color: var(--text-light);
}

.project-meta em {
    color: var(--primary-color);
    font-weight: 500;
}

.project-toggle {
    color: var(--primary-color);
    font-size: 1rem;
    transition: var(--transition);
    flex-shrink: 0;
}

.project-item.active .project-toggle {
    transform: rotate(180deg);
}

.project-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    padding: 0 1.5rem;
}

.project-item.active .project-content {
    max-height: 1000px;
    padding: 0 1.5rem 1.5rem;
}

.project-content p {
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
    color: var(--text-color);
    line-height: 1.7;
}

.project-content ul {
    margin: 0.5rem 0 1rem 1.5rem;
    font-size: 0.95rem;
    color: var(--text-color);
}

.project-content ul li {
    margin-bottom: 0.5rem;
}

.project-content a {
    color: var(--primary-color);
}

.project-content a:hover {
    text-decoration: underline;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.project-tags span {
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    color: var(--primary-dark);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* Presentations Grid */
.presentations-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
    max-width: 900px;
    margin: 0 auto;
}

.presentation-item {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-alt);
    border-radius: 10px;
    border-left: 3px solid var(--primary-color);
    transition: var(--transition);
}

.presentation-item:hover {
    transform: translateX(5px);
    box-shadow: var(--card-shadow);
}

.presentation-date {
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.6rem;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
    white-space: nowrap;
}

.presentation-content h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 0.25rem;
}

.presentation-content p {
    font-size: 0.85rem;
    color: var(--text-light);
    margin: 0;
}

/* Featured Awards */
.award-featured {
    background: linear-gradient(135deg, #dbeafe 0%, #e0f2fe 100%);
    border: 2px solid var(--primary-color);
}

.award-featured .award-year {
    background: var(--primary-dark);
}

/* Timeline Courses */
.timeline-courses {
    font-size: 0.85rem !important;
    color: var(--text-light) !important;
    margin-top: 0.5rem;
}

/* Contact Section */
.contact-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.contact-intro {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    font-size: 1.05rem;
}

.contact-item i {
    color: var(--primary-color);
    font-size: 1.2rem;
}

.social-links-large {
    justify-content: center;
}

.social-links-large a {
    width: 50px;
    height: 50px;
    font-size: 1.3rem;
}

/* Footer */
.footer {
    background: var(--text-color);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer p {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 2rem;
        gap: 1rem;
        box-shadow: var(--card-shadow);
        transform: translateY(-150%);
        opacity: 0;
        transition: var(--transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .hero {
        padding: 6rem 0 3rem;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }

    .hero-image {
        max-width: 250px;
        margin: 0 auto;
    }

    .hero-content h1 {
        font-size: 2.25rem;
    }

    .hero-description {
        margin: 0 auto 2rem;
    }

    .hero-links {
        justify-content: center;
        flex-wrap: wrap;
    }

    .social-links {
        justify-content: center;
    }

    .section {
        padding: 3.5rem 0;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .timeline::before {
        left: 8px;
    }

    .timeline-item {
        padding-left: 40px;
    }

    .timeline-marker {
        width: 18px;
        height: 18px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .hero-content h1 {
        font-size: 1.75rem;
    }

    .btn {
        padding: 0.6rem 1.2rem;
        font-size: 0.9rem;
    }

    .research-grid,
    .awards-grid {
        grid-template-columns: 1fr;
    }

    .project-header {
        padding: 1rem;
    }

    .project-header-content h3 {
        font-size: 1rem;
    }

    .presentations-grid {
        grid-template-columns: 1fr;
    }

    .presentation-item {
        flex-direction: column;
        gap: 0.5rem;
    }
}