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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #ffffff;
    --bg-alt: #f9fafb;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.nav-logo img {
    width: 5%;
    height: 5%;
    position: center;
    padding:0px;
    margin: 0px;
}
.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    transition: all 0.3s ease;
}

/* Hero Section */
.hero {
    margin-top: 70px;
    padding: 80px 20px;
    background: linear-gradient(135deg, hsl(229, 100%, 18%) 65%, hsl(358, 99%, 35%) 95%);
    color: white;
}

/* .hero {
    margin-top: 70px;
    padding: 80px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
} */

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.8;
}

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

.btn {
    padding: 12px 30px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
}

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

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

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

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

.hero-image {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 300px;
    height: 300px;
    border-radius: 50%;
    overflow: hidden;
    justify-self: center;
}

.hero-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    border: 5px solid rgba(255, 255, 255, 0.3);
    box-shadow: var(--shadow-lg);
    position: relative;
    z-index: 1;
    display: block;
}

.profile-placeholder {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 120px;
    color: white;
    background-color: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    border: 5px solid rgba(255, 255, 255, 0.3);
    z-index: 0;
}

/* Sections */
.section {
    padding: 80px 20px;
}

.section-alt {
    padding: 80px 20px;
    background-color: var(--bg-alt);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    text-align: center;
    color: var(--text-color);
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

/* About Section */
.about-content {
    max-width: 100%;
    margin: 0 auto;
}

#about .container {
    max-width: 1200px;
}

.about-text p {
    font-size: 1.1rem;
    margin-bottom: 1.2rem;
    color: var(--text-light);
    line-height: 1.8;
}

.skills {
    margin-top: 2rem;
}

.skills h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.skill-tag {
    padding: 8px 20px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

/* Research Section */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.research-card {
    background-color: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    text-align: center;
}

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

.research-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.research-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

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

/* Publications Section */
.publications-list {
    max-width: 960px;
    margin: 0 auto;
}

.publication-category-title {
    font-size: 2rem;
    font-weight: 650;
    color: var(--text-color);
    margin: 3rem 0 1.5rem 0;
    text-align: center;
    position: relative;
    padding-bottom: 0.5rem;
}

.publication-category-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

.publication-category-title:first-of-type {
    margin-top: 0;
}

.publication-item {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1rem;
    padding: 0.8rem 1rem;
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

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

.publication-number {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-color);
    min-width: 50px;
}

.publication-year {
    font-size: 1.0rem;
    font-weight: 600;
    color: var(--green-color);
    min-width: 50px;
}

.publication-content h3 {
    font-size: 1.1rem;
    margin-bottom: 0.2rem;
    color: var(--text-color);
}

.publication-content h3 a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

.publication-content h3 a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

.publication-authors {
    color: var(--text-light);
    margin-bottom: 0.3rem;
    font-style: italic;
}

.publication-venue {
    color: var(--text-light);
    margin-bottom: 0.5rem;
}

.publication-links {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.publication-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.publication-link:hover {
    color: var(--secondary-color);
}

/* Education Section */
.education-timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    padding-left: 2rem;
}

.education-timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, var(--primary-color), var(--secondary-color));
}

.education-item {
    display: flex;
    gap: 2rem;
    margin-bottom: 3rem;
    position: relative;
    padding-left: 2rem;
}

.education-item::before {
    content: '';
    position: absolute;
    left: -8px;
    top: 0;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background-color: var(--primary-color);
    border: 3px solid white;
    box-shadow: 0 0 0 3px var(--primary-color);
}

.education-year {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary-color);
    min-width: 150px;
}

.education-content h3 {
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.education-institution {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.education-content p {
    color: var(--text-light);
}

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

.contact-info {
    margin-bottom: 3rem;
}

.contact-item {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
    align-items: flex-start;
}

.contact-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-top: 0.3rem;
}

.contact-item h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

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

.social-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.social-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-color);
    padding: 1.5rem;
    border-radius: 12px;
    background-color: white;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    min-width: 120px;
}

.social-link:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    color: var(--primary-color);
}

.social-link i {
    font-size: 2rem;
    color: var(--primary-color);
}

.social-link span {
    font-weight: 500;
}

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

.link-category {
    background-color: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

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

.link-category h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.link-category h3 i {
    color: var(--primary-color);
}

.links-list {
    list-style: none;
    padding: 0;
}

.links-list li {
    margin-bottom: 0.8rem;
}

.links-list a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.links-list a:hover {
    color: var(--primary-color);
}

.links-list a::before {
    content: '→';
    color: var(--primary-color);
    margin-right: 0.5rem;
}

/* Software Section */
.software-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 1.6rem;
    margin-top: 1.6rem;
}

.software-card {
    background-color: white;
    padding: 1.6rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    height: 100%;
}

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

.software-icon {
    font-size: 3.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.software-card h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
    text-align: center;
}

.software-subtitle {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
    text-align: center;
    font-style: italic;
    font-weight: 500;
}

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

.software-features {
    margin-bottom: 1.5rem;
}

.software-features h3 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.software-features ul {
    list-style: none;
    padding: 0;
}

.software-features li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-light);
}

.software-features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

.software-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    justify-content: flex-start;
    margin-top: auto;
}

.software-links .btn {
    flex: 1;
    min-width: 140px;
    text-align: center;
}

.software-info {
    max-width: 900px;
    margin: 0 auto;
}

/* Software Links Section */
.software-links-section {
    max-width: 1000px;
    margin: 0 auto;
}

.software-category {
    margin-bottom: 3rem;
}

.software-category-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
}

.software-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.5rem;
}

.software-list-item {
    padding: 1rem;
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    line-height: 1.8;
    height: 100%;
}

.software-list-item:hover {
    box-shadow: var(--shadow-lg);
    transform: translateX(5px);
}

.software-link {
    font-weight: 600;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

.software-link:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

.software-list-item span.software-link {
    color: var(--text-color);
    cursor: default;
}

.software-list-item span.software-link:hover {
    color: var(--text-color);
    text-decoration: none;
}

.software-list-item-highlight {
    padding: 1.5rem;
}

.software-link-title {
    display: block;
    text-align: center;
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
}

.software-list-item-highlight .software-description {
    text-align: left;
    margin-left: 0;
    display: block;
}

.software-list-3col {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.2rem;
}

.software-list-2col {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.5rem;
}

@media (max-width: 900px) {
    .software-list-3col {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 600px) {
    .software-list-3col {
        grid-template-columns: 1fr;
    }
    .software-list-2col {
        grid-template-columns: 1fr;
    }
}

.software-description {
    color: var(--text-light);
    margin-left: 0.3rem;
}

/* Active nav link */
.nav-link.active {
    color: var(--primary-color);
    font-weight: 600;
}

/* Footer */
.footer {
    background-color: var(--text-color);
    color: white;
    padding: 2rem 20px;
    text-align: center;
}

.footer-note {
    margin-top: 0.5rem;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow);
        padding: 2rem 0;
    }

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

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

    .hero-title {
        font-size: 2.5rem;
    }

    .profile-placeholder {
        width: 200px;
        height: 200px;
        font-size: 80px;
    }

    .section-title {
        font-size: 2rem;
    }

    .publication-item {
        flex-direction: column;
        gap: 1rem;
    }

    .education-item {
        flex-direction: column;
        gap: 1rem;
        padding-left: 1rem;
    }

    .education-timeline {
        padding-left: 1rem;
    }

    .education-year {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

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

    .social-links {
        gap: 1rem;
    }

    .social-link {
        min-width: 100px;
        padding: 1rem;
    }

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

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

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Selection Color */
::selection {
    background-color: var(--primary-color);
    color: white;
}