/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --light-bg: #f8f9fa;
    --white: #ffffff;
    --gray: #6c757d;
    --light-gray: #ecf0f1;
    --border-color: #dee2e6;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    font-size: 16px;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
nav {
    background-color: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.nav-brand {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: 0.5rem;
}

.nav-links li {
    margin: 0;
}

.nav-links a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.nav-links a:hover,
.nav-links a.active {
    background-color: var(--secondary-color);
    color: var(--white);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--white);
    padding: 8rem 0 6rem;
    text-align: center;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.tagline {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

.btn {
    padding: 0.75rem 2rem;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

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

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

/* Page Header */
.page-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--white);
    padding: 4rem 0 3rem;
    text-align: center;
}

.page-header h1 {
    font-size: 2.8rem;
    font-weight: 700;
}

/* Sections */
.section {
    padding: 4rem 0;
}

.section h2 {
    font-size: 2.2rem;
    margin-bottom: 2rem;
    color: var(--primary-color);
    text-align: center;
    padding-bottom: 1rem;
    border-bottom: 3px solid var(--secondary-color);
}
Welcome Section */
.welcome-content {
    max-width: 900px;
    margin: 0 auto;
}
.profile-section {
    text-align: center;
    margin-bottom: 2rem;
}

.profile-photo {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
    border: 4px solid var(--secondary-color);
}
.welcome-content > p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 2rem;
    text-align: center;
    color: var(--gray);
}

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

.quick-link {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-decoration: none;
    transition: all 0.3s ease;
    border-left: 4px solid var(--secondary-color);
}

.quick-link:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.quick-link h3 {
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

.quick-link p {
    color: var(--gray);
    font-size: 0.95rem;
}

/* About Section */
.about-main,
.about-section {
    margin-bottom: 3rem;
}

.about-header {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 2rem;
    align-items: start;
    margin-bottom: 2rem;
}

.about-photo {
    width: 250px;
    height: 250px;
    border-radius: 8px;
    object-fit: cover;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
    border: 3px solid var(--secondary-color);
}

.about-intro h2 {
    margin-top: 0;
}

.about-intro p {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--gray);
}

.about-main p,
.about-section p {
    font-size: 1rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    color: var(--gray);
}

.timeline {
    margin-top: 1.5rem;
}

.timeline-item {
    background-color: var(--light-bg);
    padding: 1.5rem;
    margin-bottom: 1rem;
    border-left: 4px solid var(--secondary-color);
    border-radius: 4px;
}

.timeline-date {
    color: var(--secondary-color);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.timeline-item p {
    margin-bottom: 0.5rem;
}

.thesis-title {
    font-size: 0.95rem;
    margin-top: 0.75rem !important;
    color: var(--secondary-color);
    font-weight: 500;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 1.5rem;
}

.skill-category {
    background-color: var(--white);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.skill-category h3 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.skill-category ul {
    list-style: none;
}

.skill-category li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--light-gray);
}

.skill-category li:last-child {
    border-bottom: none;
}

/* Research Section */
.interest-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    list-style: none;
    margin-top: 1rem;
}

.interest-list li {
    background-color: var(--white);
    padding: 1rem 1.5rem;
    border-left: 4px solid var(--secondary-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    border-radius: 4px;
}

.project-list {
    margin-top: 1.5rem;
}

.project-card {
    background-color: var(--white);
    padding: 2rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
    border-top: 4px solid var(--secondary-color);
    transition: all 0.3s ease;
}

.project-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.project-status {
    color: #27ae60;
    font-weight: 600;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
}

.project-card p {
    color: var(--gray);
    line-height: 1.7;
    margin-bottom: 1rem;
}

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

.project-keywords span {
    background-color: var(--light-bg);
    color: var(--secondary-color);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.research-collaboration {
    background-color: var(--light-bg);
    padding: 2rem;
    border-radius: 8px;
    margin-top: 2rem;
}

.research-collaboration p {
    color: var(--gray);
    margin-bottom: 1rem;
}

.research-collaboration a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
}

.research-collaboration a:hover {
    text-decoration: underline;
}

/* Teaching Section */
.courses {
    margin-top: 1.5rem;
}

.course-card {
    background-color: var(--white);
    padding: 2rem;
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
    border-left: 4px solid var(--secondary-color);
}

.course-period,
.course-level {
    color: var(--secondary-color);
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.course-content {
    margin-top: 1rem;
}

.course-content h4 {
    margin-top: 1rem;
    margin-bottom: 0.75rem;
    color: var(--primary-color);
    font-weight: 600;
}

.course-content ul {
    list-style-position: inside;
    color: var(--gray);
    line-height: 1.8;
    margin-left: 1rem;
}

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

.course-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1.5rem;
}

.tag {
    background-color: var(--secondary-color);
    color: var(--white);
    padding: 0.35rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
}

.supervision,
.tutorials {
    background-color: var(--light-bg);
    padding: 1.5rem;
    border-radius: 8px;
    margin-top: 1.5rem;
}

.supervision p,
.tutorials p {
    color: var(--gray);
    margin-bottom: 1rem;
}

.supervision-areas,
.tutorial-list {
    list-style-position: inside;
    color: var(--gray);
    line-height: 1.8;
    margin-left: 1rem;
}

.supervision-areas li,
.tutorial-list li {
    margin-bottom: 0.5rem;
}

/* Publications Section */
.publications-list {
    margin-top: 1.5rem;
}

.publication-item {
    background-color: var(--white);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    border-left: 4px solid var(--secondary-color);
}

.publication-item h3 {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.authors {
    color: var(--gray);
    font-style: italic;
    margin-bottom: 0.5rem;
}

.venue {
    color: var(--secondary-color);
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.thesis-supervisors {
    color: var(--gray);
    font-style: italic;
    font-size: 0.95rem;
    margin-bottom: 0.75rem;
}

.abstract {
    color: var(--gray);
    line-height: 1.7;
    margin-bottom: 1rem;
}

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

.pub-link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
}

.pub-link:hover {
    text-decoration: underline;
}

/* Contact Section */
.contact-intro {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 2rem;
}

.contact-intro p {
    font-size: 1.1rem;
    color: var(--gray);
    line-height: 1.8;
}

.contact-info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.contact-block {
    background-color: var(--light-bg);
    padding: 2rem;
    border-radius: 8px;
    border-top: 4px solid var(--secondary-color);
}

.contact-block h3 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.contact-block p {
    color: var(--gray);
    line-height: 1.7;
}

.contact-block a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
}

.contact-block a:hover {
    text-decoration: underline;
}

.contact-section {
    background-color: var(--white);
    padding: 2rem;
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.contact-section h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--secondary-color);
    padding-bottom: 0.75rem;
}

.contact-section p {
    color: var(--gray);
    margin-bottom: 1rem;
}

.contact-section ul {
    list-style-position: inside;
    color: var(--gray);
    margin-left: 1rem;
}

.contact-section ul li {
    margin-bottom: 0.5rem;
}

.contact-section a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
}

.contact-section a:hover {
    text-decoration: underline;
}

.contact-social {
    text-align: center;
    padding: 2rem 0;
}

.social-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 1.5rem;
}

.social-link {
    padding: 0.75rem 1.5rem;
    background-color: var(--secondary-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 5px;
    transition: all 0.3s ease;
    font-weight: 600;
}

.social-link:hover {
    background-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

/* Footer */
footer {
    background-color: var(--primary-color);
    color: var(--white);
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

footer p {
    margin: 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    nav .container {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        flex-wrap: wrap;
        font-size: 0.9rem;
        gap: 0.25rem;
    }

    .nav-links a {
        padding: 0.4rem 0.7rem;
        font-size: 0.9rem;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    .tagline {
        font-size: 1.1rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
        gap: 0.75rem;
    }

    .btn {
        width: 100%;
        max-width: 300px;
    }

    .page-header h1 {
        font-size: 1.8rem;
    }

    .about-header {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .about-photo {
        width: 100%;
        max-width: 250px;
        margin: 0 auto;
    }

    .profile-photo {
        width: 150px;
        height: 150px;
    }

    .section h2 {
        font-size: 1.6rem;
        margin-bottom: 1.5rem;
    }

    .section h3 {
        font-size: 1.2rem;
    }

    .quick-links,
    .project-grid,
    .interest-list,
    .skills-grid,
    .contact-info-grid {
        grid-template-columns: 1fr;
    }

    .hero-buttons,
    .social-links {
        flex-direction: column;
        align-items: center;
    }

    .publication-links {
        flex-wrap: wrap;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero {
        padding: 4rem 0 3rem;
    }

    .hero h1 {
        font-size: 1.8rem;
    }

    .tagline {
        font-size: 1rem;
    }

    .section {
        padding: 2rem 0;
    }

    .section h2 {
        font-size: 1.4rem;
    }

    .page-header {
        padding: 2rem 0 1.5rem;
    }

    .page-header h1 {
        font-size: 1.5rem
    }

    .nav-links li {
        margin: 0.5rem 1rem;
    }

    .section h2 {
        font-size: 2rem;
    }

    .project-grid,
    .interest-list {
        grid-template-columns: 1fr;
    }
}