:root {
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --accent-color: #3498db;
    --gradient-start: #2c3e50;
    --gradient-end: #3498db;
    --background-color: #f5f6fa;
    --text-color: #2c3e50;
    --text-muted: #7f8c8d;
    --border-color: #e0e6ed;
    --card-bg: #ffffff;
    --content-width: 90%;
    --content-max-width: 1200px;
    --spacing-unit: 2rem;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --header-height: 70px;
    --side-padding: 2rem;
    --font-family: Arial, Helvetica, sans-serif;
    --line-height-heading: 1.3;
    --line-height-body: 1.6;
    --font-size-h1: 2.3rem;
    --font-size-h2: 2rem;
    --font-size-h3: 1.5rem;
    --font-size-h4: 1.2rem;
    --font-size-h5: 1.1rem;
    --font-size-h6: 1rem;
    --font-size-body: 1rem;
    --font-size-small: 0.9rem;
    --font-size-xs: 0.8rem;
    --letter-spacing-tight: -0.02em;
    --letter-spacing-normal: 0;
    --letter-spacing-wide: 0.05em;
}

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

body {
    background-color: var(--background-color);
    color: var(--text-color);
    font-family: var(--font-family);
    font-size: var(--font-size-body);
    font-weight: 400;
    line-height: var(--line-height-body);
    margin: 0;
    padding-top: var(--header-height);
    height: 100vh;
    overflow: hidden;
    letter-spacing: var(--letter-spacing-normal);
}

/* Header Navigation */
.side-nav {
    width: 100%;
    height: var(--header-height);
    position: fixed;
    top: 0;
    left: 0;
    background: var(--card-bg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--shadow-md);
    z-index: 1000;
}

.nav-content {
    width: var(--content-width);
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: 0 var(--side-padding);
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
}

.nav-header {
    display: flex;
    align-items: center;
    margin-right: 2rem;
}

.nav-header h1 {
    font-family: var(--font-family);
    font-size: var(--font-size-h4);
    font-weight: 600;
    margin: 0;
    color: var(--primary-color);
    letter-spacing: var(--letter-spacing-tight);
}

.nav-header .title {
    display: none;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-link {
    padding: 0.5rem 1rem;
    background: transparent;
    border: none;
    color: var(--text-color);
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: var(--border-radius);
    letter-spacing: var(--letter-spacing-normal);
    position: relative;
}

.nav-link:hover {
    background: var(--accent-color);
    color: white;
}

.nav-link.active {
    background: var(--accent-color);
    color: white;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--accent-color);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 80%;
}

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

/* Main Content */
.main-content {
    width: var(--content-width);
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: 0 var(--side-padding);
    height: calc(100vh - var(--header-height) - var(--header-height));
    overflow-y: auto;
}

/* Hero Section */
.hero-section {
    display: flex;
    align-items: center;
    gap: 3.5rem;
    padding: 1.2rem 0;
    max-width: 900px;
    /* margin: 0 auto; */
    position: relative;
}

.hero-image {
    flex-shrink: 0;
    position: relative;
    width: 180px;
    height: 180px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    padding: 4px;
    box-shadow: var(--shadow-lg);
}

.hero-section img {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--card-bg);
}


.hero-image::before {
    content: '';
    position: absolute;
    top: -4px;
    left: -4px;
    right: -4px;
    bottom: -4px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    border-radius: 50%;
    opacity: 0.2;
    z-index: -1;
}

.hero-content {
    flex: 1;
    text-align: left;
    max-width: 600px;
    position: relative;
}

.hero-content::after {
    content: '';
    position: absolute;
    bottom: -1rem;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(to right, var(--gradient-start), var(--gradient-end));
    border-radius: 3px;
    opacity: 0.7;
}

.hero-section h1 {
    font-family: var(--font-family);
    font-size: var(--font-size-h1);
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
    letter-spacing: var(--letter-spacing-tight);
    line-height: 1.2;
}

.hero-section .title {
    font-family: var(--font-family);
    font-size: var(--font-size-h4);
    font-weight: 400;
    color: var(--accent-color);
    margin-bottom: 0.5rem;
    line-height: 1.4;
    letter-spacing: var(--letter-spacing-normal);
}

/* Mobile Navigation */
.mobile-menu-button {
    display: none;
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    position: absolute;
    right: 1rem;
}

.close-menu-button {
    display: none;
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    position: absolute;
    right: 60px;
}

@media (max-width: 768px) {
    .main-content{
        padding:0;
    }
    .mobile-menu-button {
        display: block;
        height: 50%;
        right: 1rem;
        
    }

    .side-nav {
        justify-content: space-between;
        padding: 0 1rem;
    }

    .nav-header {
        margin-right: 0;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: var(--header-height);
        right: 0;
        width: 30%;
        background: var(--card-bg);
        padding: 1rem;
        box-shadow: var(--shadow-md);
        flex-direction: column;
        gap: 1rem;
        z-index: 1000;
        transition: transform 0.3s ease;
        transform: translateX(100%);
    }

    .nav-links.active {
        display: flex;
        transform: translateX(0);
    }

    .nav-link {
        width: 100%;
        text-align: center;
        padding: 0.75rem;
    }

    .social-links {
        display: none;
    }

    .hero-section {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 2rem;
        padding: 2rem 0;
    }

    .hero-image {
        width: 50%;
        height: auto;
    }

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

    .hero-section .title {
        font-size: 1.1rem;
    }

    .hero-content::after {
        left: 50%;
        transform: translateX(-50%);
    }
    .skill-item{
        gap: 5px;
    }
    .skills-container{
       padding: 0;
    }

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

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

    .nav-header h1 {
        font-size: 1.1rem;
    }

    .hero-section {
        padding: 1.5rem 0;
        gap: 1.5rem;
    }

    .hero-image {
        width: 140px;
        height: 140px;
    }

    .hero-section h1 {
        font-size: 2rem;
    }

    .hero-section .title {
        font-size: 1rem;
    }
}

/* Section */
.section {
    display: none;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.5s ease;
}

.section.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
    animation: fadeIn 0.5s ease forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Scrollbar Styling */
.section::-webkit-scrollbar {
    width: 8px;
}

.section::-webkit-scrollbar-track {
    background: var(--background-color);
    border-radius: 4px;
}

.section::-webkit-scrollbar-thumb {
    background: var(--accent-color);
    border-radius: 4px;
}

.section::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

/* Make sections scrollable individually */
.section-inner {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: var(--spacing-unit);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-unit);
    border: 1px solid var(--border-color);
}

.section-inner:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.section-header {
    margin-bottom: var(--spacing-unit);
    position: relative;
}

.section-label {
    font-family: var(--font-family);
    font-size: var(--font-size-xs);
    font-weight: 600;
    letter-spacing: var(--letter-spacing-wide);
    text-transform: uppercase;
    color: var(--accent-color);
}

.section-header h2 {
    font-family: var(--font-family);
    font-size: 2rem;
    color: var(--primary-color);
    margin-top: 0.5rem;
    position: relative;
    display: inline-block;
}

.section-header h2::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -8px;
    width: 60px;
    height: 2px;
    background: linear-gradient(to right, var(--gradient-start), var(--gradient-end));
    border-radius: 2px;
    opacity: 0.7;
}

/* Skills */
.skills-container {
    background-color: #f9f9f9;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.skill-group {
    margin-bottom: 20px;
}

.skill-header {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
}

.skill-header h3 {
    margin-left: 10px;
    font-size: 1.5em;
    color: #333;
}

.skill-items {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 15px;
}

.skill-item {
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 5px;
    padding: 15px;
    transition: transform 0.2s;
}

.skill-item:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.skill-item i {
    color: #007bff;
    margin-right: 8px;
}

/* Publications */
.scholar-profile {
    margin-bottom: 2rem;
}

.scholar-metrics {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.metric-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.metric-label {
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.metric-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.scholar-link {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: #ffffff;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    opacity: 0.9;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.scholar-link:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.scholar-link i {
    font-size: 1.25rem;
}

.publication {
    background: var(--card-bg);
    padding: 0.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

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

.publication h4 {
    font-family: var(--font-family);
    font-size: var(--font-size-h4);
    line-height: 1.4;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--primary-color);
    letter-spacing: var(--letter-spacing-tight);
}

.publication h4 a {
    color: inherit;
    text-decoration: none;
    transition: color 0.3s ease;
}

.publication h4 a:hover {
    color: var(--accent-color);
}

.publication .authors {
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    line-height: 1.5;
    color: var(--text-color);
    opacity: 0.8;
    margin: 0.5rem 0;
    font-weight: 400;
}

.pub-meta {
    display: flex;
    gap: 1.5rem;
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
}

.citations {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
}

/* Timeline */
.timeline {
    position: relative;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 3px;
    background: linear-gradient(to bottom, var(--gradient-start), var(--gradient-end));
    opacity: 0.3;
    border-radius: 3px;
}

.timeline-entry {
    position: relative;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.timeline-entry::before {
    content: '';
    position: absolute;
    left: -2rem;
    top: 1.5rem;
    width: 1rem;
    height: 1rem;
    background: var(--accent-color);
    border-radius: 50%;
    border: 3px solid var(--card-bg);
    box-shadow: var(--shadow-sm);
}

.timeline-entry:hover {
    transform: translateX(10px);
    box-shadow: var(--shadow-md);
}

.timeline-header {
    margin-bottom: 1rem;
}

.timeline-meta {
    display: flex;
    gap: 1rem;
    font-size: var(--font-size-small);
    color: var(--text-muted);
    margin-top: 0.5rem;
}

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

.project-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    padding: 1.5rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

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

.project-header h3 {
    font-size: var(--font-size-h4);
    margin-bottom: 0.5rem;
}

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

.tech-tags span {
    background: var(--accent-color);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.9rem;
}

.project-actions {
    margin-top: 1rem;
}

.project-actions a {
    display: inline-block;
    margin-top: 0.5rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: bold;
    transition: color 0.3s ease;
}

.project-actions a:hover {
    color: var(--accent-color);
}

/* Grid System */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-unit);
}

.grid-item {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: var(--spacing-unit);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.grid-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family);
    color: var(--primary-color);
    line-height: var(--line-height-heading);
    font-weight: 600;
    margin: 0 0 1rem;
}

h1 {
    font-size: var(--font-size-h1);
    letter-spacing: var(--letter-spacing-tight);
}

h2 {
    font-size: var(--font-size-h2);
    letter-spacing: var(--letter-spacing-normal);
}

h3 {
    font-size: var(--font-size-h3);
    letter-spacing: var(--letter-spacing-normal);
}

h4 {
    font-size: var(--font-size-h4);
    margin-bottom: 1rem;
    color: var(--text-color);
}

h5 {
    font-size: var(--font-size-h5);
    margin-bottom: 1rem;
    color: var(--text-color);
}

h6 {
    font-size: var(--font-size-h6);
    margin-bottom: 1rem;
    color: var(--text-color);
}

p {
    margin-bottom: 1rem;
    color: var(--text-color);
}

.year-section {
    margin-bottom: 2.5rem;
}

.year-header {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--accent-color);
    position: relative;
    display: inline-block;
}

.year-header::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 50px;
    height: 2px;
    background: linear-gradient(to right, var(--gradient-start), var(--gradient-end));
}

.year-publications {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .year-section {
        margin-bottom: 2rem;
    }

    .year-header {
        font-size: 1.2rem;
        margin-bottom: 1.25rem;
    }

    .year-publications {
        gap: 1.25rem;
    }
}

@media (max-width: 480px) {
    .year-section {
        margin-bottom: 1.5rem;
    }

    .year-header {
        font-size: 1.1rem;
        margin-bottom: 1rem;
    }

    .year-publications {
        gap: 1rem;
    }
}

.paper-options {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.paper-option {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.paper-option:hover {
    transform: translateY(-2px);
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    border-color: transparent;
}

.paper-option i {
    font-size: 1rem;
    color: var(--accent-color);
    transition: all 0.3s ease;
}

.paper-option:hover i {
    color: white;
}

@media (max-width: 768px) {
    .paper-options {
        gap: 0.75rem;
    }

    .paper-option {
        padding: 0.4rem 0.8rem;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .paper-options {
        gap: 0.5rem;
    }

    .paper-option {
        padding: 0.35rem 0.7rem;
        font-size: 0.8rem;
    }
}

/* Footer */
.footer {
    background: var(--card-bg);
    padding: 0;
    border-top: 1px solid var(--border-color);
    box-shadow: 0 -2px 4px rgba(0, 0, 0, 0.05);
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    height: var(--header-height);
    display: flex;
    align-items: center;
}

.footer-content {
    width: var(--content-width);
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: 0 var(--side-padding);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.footer-social {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin: 0;
    width: 100%;
    justify-content: space-between;
}

.footer-social a {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--background-color);
    color: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 1.5rem;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.footer-social a:hover {
    transform: scale(1.1);
    background: var(--accent-color);
    color: white;
}

.footer-text {
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    color: var(--text-muted);
    margin: 0;
    letter-spacing: var(--letter-spacing-normal);
    font-weight: 400;
}

/* Remove footer bottom as it's not needed in fixed compact footer */
.footer-bottom {
    display: none;
}

@media (max-width: 768px) {
    .footer-content {
        padding: 0 1rem;
        justify-content: center;
        gap: 1.5rem;
    }

    .footer {
        height: auto;
        padding: 1rem 0;
    }

    .footer-social {
        gap: 1.25rem;
    }

    .footer-social a {
        width: 34px;
        height: 34px;
        font-size: 1rem;
    }

    .footer-text {
        display: none;
    }
}

@media (max-width: 480px) {
    .footer-content {
        gap: 1rem;
    }

    .footer-social {
        gap: 1rem;
    }

    .footer-social a {
        width: 32px;
        height: 32px;
        font-size: 0.95rem;
    }
}

.social-icons {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

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

    .social-icons {
        gap: 1.25rem;
    }

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

@media (max-width: 480px) {
    .social-icons {
        gap: 1rem;
    }
}

/* Responsive Typography */
@media (max-width: 768px) {
    :root {
        --font-size-h1: 2.25rem;
        --font-size-h2: 1.75rem;
        --font-size-h3: 1.35rem;
        --font-size-h4: 1.15rem;
    }
}

@media (max-width: 480px) {
    :root {
        --font-size-h1: 2rem;
        --font-size-h2: 1.5rem;
        --font-size-h3: 1.25rem;
        --font-size-h4: 1.1rem;
    }
}

.social-icons_top {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.social-icons_top a {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--background-color);
    color: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 1.5rem;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.social-icons_top a:hover {
    transform: scale(1.1);
    background: var(--accent-color);
    color: white;
}

.recent-research {
    padding: 2rem;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    margin: 2rem 0;
}

.recent-research .section-header {
    margin-bottom: 1.5rem;
}

.research-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.research-item {
    background: var(--background-color);
    padding: 1rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease;
}

.research-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.research-item h3 {
    font-size: var(--font-size-h4);
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.research-item p {
    color: var(--text-color);
}