/* ===== BASE STYLES ===== */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --light-color: #ecf0f1;
    --dark-color: #2c3e50;
    --text-color: #333;
    --text-light: #7f8c8d;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #f8f9fa;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

h1, h2, h3, h4 {
    margin-bottom: 1rem;
    line-height: 1.2;
    color: var(--dark-color);
}

p {
    margin-bottom: 1rem;
}

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

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

ul {
    list-style: none;
}

.btn {
    display: inline-block;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    text-align: center;
}

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

.btn-primary:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 1px solid #bdc3c7;
}

.btn-secondary:hover {
    background-color: #d5dbdb;
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.9rem;
}

/* ===== HEADER ===== */
.header {
    background-color: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 15px 0;
}

.profile {
    display: flex;
    align-items: center;
    margin-bottom: 15px;
}

.profile-image {
    width: 60px;
    height: 60px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    margin-right: 15px;
}

.profile-info .name {
    font-size: 1.5rem;
    color: var(--dark-color);
}

.profile-info .title {
    color: var(--text-light);
    font-size: 0.9rem;
}

.main-nav ul {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 5px;
}

.main-nav a {
    padding: 8px 15px;
    color: var(--text-color);
    border-radius: 5px;
    transition: var(--transition);
}

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

.main-nav i {
    margin-right: 5px;
}

/* ===== HERO SECTION ===== */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 80px 0;
    margin-top: 20px;
    border-radius: 10px;
    margin-bottom: 40px;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

.hero-content h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: white;
}

.hero-content .subtitle {
    font-size: 1.2rem;
    margin-bottom: 20px;
    opacity: 0.9;
}

.hero-text p {
    font-size: 1.1rem;
    margin-bottom: 25px;
    line-height: 1.8;
}

.cta-buttons {
    display: flex;
    gap: 15px;
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.research-illustration {
    font-size: 4rem;
    opacity: 0.8;
}

/* ===== SECTIONS ===== */
.section {
    padding: 60px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-header h2 {
    font-size: 2rem;
    margin-bottom: 10px;
    color: var(--dark-color);
}

.section-header h2 i {
    margin-right: 10px;
    color: var(--secondary-color);
}

.section-description {
    color: var(--text-light);
    font-size: 1.1rem;
}

/* ===== CV SECTION ===== */
.cv-content {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 30px;
}

.cv-card {
    background: white;
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.cv-card h3 {
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--light-color);
    color: var(--primary-color);
}

.cv-card h3 i {
    margin-right: 8px;
}

.education-item {
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid #eee;
}

.education-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.education-item h4 {
    color: var(--secondary-color);
    margin-bottom: 5px;
}

.institution, .year {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 5px;
}

.awards-list li, .skills-list li {
    margin-bottom: 10px;
    padding-left: 15px;
    position: relative;
}

.awards-list li:before, .skills-list li:before {
    content: "•";
    color: var(--secondary-color);
    position: absolute;
    left: 0;
}

.experience-item {
    margin-bottom: 25px;
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
    flex-wrap: wrap;
}

.experience-header h4 {
    color: var(--primary-color);
    margin-bottom: 0;
}

.company, .duration {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-left: 10px;
}

.responsibilities {
    padding-left: 20px;
}

.responsibilities li {
    margin-bottom: 8px;
    position: relative;
}

.responsibilities li:before {
    content: "•";
    color: var(--secondary-color);
    position: absolute;
    left: -15px;
}

.skill-item {
    margin-bottom: 15px;
}

.skill-name {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
}

.skill-bar {
    height: 8px;
    background-color: #ecf0f1;
    border-radius: 4px;
    overflow: hidden;
}

.skill-level {
    height: 100%;
    background-color: var(--secondary-color);
    border-radius: 4px;
}

.download-cv {
    text-align: center;
    margin-top: 30px;
}

/* ===== RESEARCH SECTION ===== */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
}

.research-card {
    background: white;
    border-radius: 8px;
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.research-icon {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 15px;
}

.research-card h3 {
    margin-bottom: 15px;
    color: var(--primary-color);
}

.research-card p {
    margin-bottom: 20px;
    color: var(--text-light);
}

/* ===== PROJECTS SECTION ===== */
.projects-timeline {
    position: relative;
    padding-left: 50px;
}

.projects-timeline:before {
    content: "";
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: var(--light-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 40px;
}

.timeline-marker {
    position: absolute;
    left: -50px;
    top: 0;
    width: 40px;
    height: 40px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.9rem;
}

.timeline-content {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.timeline-header h3 {
    color: var(--primary-color);
    margin-bottom: 0;
}

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

.project-tags {
    display: flex;
    gap: 10px;
    margin: 15px 0;
    flex-wrap: wrap;
}

.tag {
    background-color: var(--light-color);
    color: var(--text-light);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
}

/* ===== PUBLICATIONS SECTION ===== */
.publications-list {
    max-width: 800px;
    margin: 0 auto;
}

.publication-item {
    background: white;
    padding: 25px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.publication-citation {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    font-size: 0.9rem;
}

.publication-authors {
    font-weight: 600;
    color: var(--primary-color);
}

.publication-year {
    color: var(--text-light);
}

.publication-title {
    color: var(--secondary-color);
    margin-bottom: 10px;
}

.publication-journal {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 15px;
}

.publication-links {
    display: flex;
    gap: 15px;
}

.publication-link {
    color: var(--text-light);
    font-size: 0.9rem;
    transition: var(--transition);
}

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

.publication-link i {
    margin-right: 5px;
}

.view-all-publications {
    text-align: center;
    margin-top: 30px;
}

/* ===== REFERENCES SECTION ===== */
.references-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.reference-card {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.reference-header {
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid #eee;
}

.reference-header h3 {
    color: var(--primary-color);
    margin-bottom: 5px;
}

.reference-title, .reference-institution {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 3px;
}

.reference-description {
    color: var(--text-light);
    margin-bottom: 15px;
    font-size: 0.95rem;
}

.reference-contact p {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 8px;
}

.reference-contact i {
    margin-right: 8px;
    color: var(--secondary-color);
}

/* ===== CONTACT SECTION ===== */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.contact-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.contact-card {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    text-align: center;
}

.contact-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

.contact-card h3 i {
    margin-right: 8px;
}

.contact-card p {
    color: var(--text-light);
    margin-bottom: 0;
}

.contact-card a {
    color: var(--secondary-color);
}

.contact-form {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--dark-color);
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

button[type="submit"] {
    width: 100%;
    padding: 12px;
}

/* ===== FOOTER ===== */
.footer {
    background-color: var(--dark-color);
    color: white;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    color: white;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-section ul {
    margin-bottom: 0;
}

.footer-section li {
    margin-bottom: 10px;
}

.footer-section a {
    color: var(--light-color);
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--secondary-color);
}

.social-links {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.social-link {
    display: flex;
    align-items: center;
    color: var(--light-color);
    transition: var(--transition);
}

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

.social-link i {
    margin-right: 10px;
    width: 20px;
    text-align: center;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--light-color);
    font-size: 0.9rem;
}

.footer-bottom i {
    color: var(--accent-color);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content h2 {
        font-size: 2rem;
    }

    .cta-buttons {
        justify-content: center;
    }

    .cv-content {
        grid-template-columns: 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .contact-info {
        grid-template-columns: 1fr;
    }

    .main-nav ul {
        justify-content: center;
    }

    .main-nav a {
        padding: 6px 10px;
        font-size: 0.9rem;
    }
}

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

    .hero-content h2 {
        font-size: 1.8rem;
    }

    .section-header h2 {
        font-size: 1.8rem;
    }

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

    .projects-timeline {
        padding-left: 30px;
    }

    .timeline-marker {
        left: -30px;
        width: 30px;
        height: 30px;
        font-size: 0.8rem;
    }
}