:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-light: #94a3b8;
    --background: #ffffff;
    --surface: #f8fafc;
    --border: #e2e8f0;
    --gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    --font-size-6xl: 3.75rem;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-primary);
    background: var(--background);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Utility Classes */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    text-decoration: none;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background: var(--surface);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

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

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 4rem;
}

.nav-logo {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

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

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 0.25rem;
}

.bar {
    width: 1.5rem;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition);
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 4rem;
        left: -100%;
        width: 100%;
        height: calc(100vh - 4rem);
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(10px);
        flex-direction: column;
        align-items: center;
        justify-content: flex-start;
        padding-top: 2rem;
        transition: var(--transition);
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: rotate(45deg) translate(0.35rem, 0.35rem);
    }

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

    .nav-toggle.active .bar:nth-child(3) {
        transform: rotate(-45deg) translate(0.35rem, -0.35rem);
    }
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    position: relative;
    padding-top: 4rem;
}

.hero-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text {
    animation: fadeInUp 1s ease-out;
}

.hero-title {
    margin-bottom: 1.5rem;
}

.hero-name {
    display: block;
    font-size: var(--font-size-5xl);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.hero-role {
    display: block;
    font-size: var(--font-size-2xl);
    font-weight: 500;
    color: var(--primary-color);
    min-height: 2rem;
}

.hero-description {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-image {
    display: flex;
    justify-content: center;
    animation: fadeInRight 1s ease-out 0.3s both;
}

.image-container {
    position: relative;
    width: 400px;
    height: 400px;
    border-radius: 50%;
    overflow: hidden;
    background: var(--gradient);
    padding: 0.5rem;
}

.profile-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    transition: var(--transition);
}

.image-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient);
    opacity: 0;
    transition: var(--transition);
    border-radius: 50%;
}

.image-container:hover .image-overlay {
    opacity: 0.1;
}

.image-container:hover .profile-img {
    transform: scale(1.05);
}

.hero-social {
    position: absolute;
    left: 2rem;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    gap: 1rem;
    animation: fadeInLeft 1s ease-out 0.6s both;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 3rem;
    height: 3rem;
    background: white;
    color: var(--text-secondary);
    border-radius: 50%;
    text-decoration: none;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.social-link:hover {
    background: var(--primary-color);
    color: white;
    transform: translateX(0.5rem);
    box-shadow: var(--shadow-lg);
}

.scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    animation: bounce 2s infinite;
}

.scroll-line {
    width: 1px;
    height: 2rem;
    background: var(--text-light);
}

.scroll-text {
    font-size: var(--font-size-sm);
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .hero-name {
        font-size: var(--font-size-4xl);
    }

    .hero-role {
        font-size: var(--font-size-xl);
    }

    .image-container {
        width: 300px;
        height: 300px;
    }

    .hero-social {
        position: static;
        transform: none;
        flex-direction: row;
        justify-content: center;
        margin-top: 2rem;
    }

    .social-link:hover {
        transform: translateY(-0.25rem);
    }
}

/* Section Styles */
.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: 1rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 50%;
    transform: translateX(-50%);
    width: 3rem;
    height: 0.25rem;
    background: var(--primary-color);
    border-radius: 0.125rem;
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
}

/* About Section */
.about {
    padding: 6rem 0;
    background: white;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-description {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: 2rem;
    text-align: justify;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-top: 3rem;
}

.stat {
    text-align: center;
    padding: 2rem;
    background: var(--surface);
    border-radius: 1rem;
    transition: var(--transition);
}

.stat:hover {
    transform: translateY(-0.5rem);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    display: block;
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: var(--font-size-base);
    color: var(--text-secondary);
    font-weight: 500;
}

@media (max-width: 768px) {
    .about-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .stat {
        padding: 1.5rem;
    }
}

/* Tech Section */
.tech {
    padding: 6rem 0;
    background: var(--surface);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.tech-category {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.tech-category:hover {
    transform: translateY(-0.5rem);
    box-shadow: var(--shadow-lg);
}

.tech-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--text-primary);
}

.tech-items {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.tech-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--surface);
    border-radius: 0.5rem;
    transition: var(--transition);
}

.tech-item:hover {
    background: var(--primary-color);
    color: white;
    transform: scale(1.05);
}

.tech-item img {
    width: 2.5rem;
    height: 2.5rem;
    filter: brightness(0) saturate(100%) invert(45%) sepia(13%) saturate(1016%) hue-rotate(203deg) brightness(93%) contrast(84%);
    transition: var(--transition);
}

.tech-item:hover img {
    filter: brightness(0) saturate(100%) invert(100%) sepia(0%) saturate(7500%) hue-rotate(109deg) brightness(109%) contrast(109%);
}

.tech-item span {
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* Projects Section */
.projects {
    padding: 6rem 0;
    background: white;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.project-card {
    background: white;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    cursor: pointer;
}

.project-card:hover {
    transform: translateY(-0.5rem);
    box-shadow: var(--shadow-xl);
}

.project-image {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(99, 102, 241, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition);
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.project-card:hover .project-image img {
    transform: scale(1.1);
}

.project-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 3rem;
    height: 3rem;
    background: white;
    color: var(--primary-color);
    border-radius: 50%;
    text-decoration: none;
    font-size: var(--font-size-lg);
    transition: var(--transition);
}

.project-link:hover {
    transform: scale(1.1);
}

.project-content {
    padding: 1.5rem;
}

.project-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.project-description {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.6;
}

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

.tag {
    background: var(--surface);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* Publications Section */
.publications {
    padding: 6rem 0;
    background: var(--surface);
}

.publications-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 4rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.stat-item {
    text-align: center;
    padding: 1.5rem;
    background: white;
    border-radius: 1rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.stat-item:hover {
    transform: translateY(-0.25rem);
    box-shadow: var(--shadow-md);
}

.stat-value {
    display: block;
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.publications-list {
    max-width: 800px;
    margin: 0 auto 3rem;
}

.publication-item {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-sm);
    margin-bottom: 1.5rem;
    transition: var(--transition);
    border-left: 4px solid var(--primary-color);
}

.publication-item:hover {
    transform: translateY(-0.25rem);
    box-shadow: var(--shadow-md);
}

.loading-placeholder {
    opacity: 0.7;
    font-style: italic;
}

.publication-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    line-height: 1.4;
}

.publication-authors {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-style: italic;
}

.publication-meta {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.publication-venue {
    background: var(--surface);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.publication-year {
    color: var(--primary-color);
    font-weight: 600;
    font-size: var(--font-size-sm);
}

.publication-citations {
    color: var(--text-light);
    font-size: var(--font-size-sm);
}

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

@media (max-width: 768px) {
    .publications-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .stat-item {
        padding: 1rem;
    }
    
    .publication-item {
        padding: 1.5rem;
    }
    
    .publication-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
}

/* Contact Section */
.contact {
    padding: 6rem 0;
    background: var(--surface);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.contact-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 3rem;
    height: 3rem;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    font-size: var(--font-size-lg);
}

.contact-details h3 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.contact-details a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.contact-details a:hover {
    color: var(--primary-color);
}

.contact-cta {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-sm);
    text-align: center;
}

.contact-cta h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.contact-cta p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

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

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

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

.footer-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border-radius: 50%;
    text-decoration: none;
    transition: var(--transition);
}

.footer-social a:hover {
    background: var(--primary-color);
    transform: translateY(-0.25rem);
}

@media (max-width: 768px) {
    .footer-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(2rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(2rem);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-2rem);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-0.5rem);
    }
    60% {
        transform: translateY(-0.25rem);
    }
}

/* Scroll animations */
.scroll-animate {
    opacity: 1;
    transform: translateY(0);
    transition: all 0.6s ease-out;
}

.scroll-animate.animate-in {
    opacity: 0;
    transform: translateY(2rem);
}

.scroll-animate.active {
    opacity: 1;
    transform: translateY(0);
}

/* Fallback: Ensure content is visible if JavaScript fails */
.scroll-animate.animate-in {
    animation: fallbackVisible 0.1s ease-out 3s forwards;
}

@keyframes fallbackVisible {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Loading states */
.loading {
    position: relative;
    overflow: hidden;
}

.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% {
        left: -100%;
    }
    100% {
        left: 100%;
    }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --background: #0f172a;
        --surface: #1e293b;
        --text-primary: #f1f5f9;
        --text-secondary: #cbd5e1;
        --text-light: #64748b;
        --border: #334155;
    }

    .nav {
        background: rgba(15, 23, 42, 0.95);
    }

    .hero {
        background: linear-gradient(135deg, #1e293b 0%, #334155 100%);
    }

    .about {
        background: var(--background);
    }

    .tech {
        background: var(--surface);
    }

    .projects {
        background: var(--background);
    }

    .contact {
        background: var(--surface);
    }

    .project-card,
    .tech-category,
    .contact-cta {
        background: var(--background);
        border: 1px solid var(--border);
    }

    .tech-item {
        background: var(--surface);
    }

    .tech-item img {
        filter: brightness(0) saturate(100%) invert(100%);
    }

    .tech-item:hover img {
        filter: brightness(0) saturate(100%) invert(100%);
    }
}