/* Base Styles */
:root {
    --primary-color: #4285f4;
    --secondary-color: #34a853;
    --dark-color: #202124;
    --light-color: #f8f9fa;
    --gray-color: #5f6368;
    --border-color: #dadce0;
    --error-color: #ea4335;
    --success-color: #34a853;
    --font-primary: 'Roboto', sans-serif;
    --font-secondary: 'Source Sans Pro', sans-serif;
    --box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
}

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

section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
    font-size: 2.5rem;
    color: var(--dark-color);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background-color: var(--primary-color);
    margin: 15px auto 0;
    border-radius: 2px;
}

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

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

img {
    max-width: 100%;
    height: auto;
}

ul {
    list-style: none;
}

/* Header */
header {
    background-color: white;
    box-shadow: var(--box-shadow);
    position: fixed;
    width: 100%;
    top: 0;
    left: 0;
    z-index: 1000;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 15px;
}

.profile-photo {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    overflow: hidden;
    border: 2px solid var(--primary-color);
    box-shadow: 0 2px 8px rgba(66, 133, 244, 0.3);
    transition: transform 0.3s ease;
}

.profile-photo:hover {
    transform: scale(1.05);
}

.profile-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
}

nav ul {
    display: flex;
}

nav li {
    margin-left: 25px;
}

nav a {
    color: var(--dark-color);
    font-weight: 500;
    padding: 5px 0;
    position: relative;
}

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

nav a:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    background: var(--primary-color);
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    text-align: center;
    padding: 180px 0 100px;
    margin-top: 60px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('../images/pattern.svg');
    background-size: cover;
    opacity: 0.1;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-content h2 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    font-weight: 700;
}

.hero-content p {
    font-size: 1.5rem;
    margin-bottom: 30px;
    font-weight: 300;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.btn {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 12px 30px;
    border-radius: 5px;
    font-weight: 500;
    transition: var(--transition);
    border: 2px solid var(--primary-color);
}

.btn:hover {
    background-color: transparent;
    color: white;
}

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

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

.btn-small {
    padding: 8px 15px;
    font-size: 0.9rem;
}

/* About Section */
.about-content {
    display: flex;
    gap: 50px;
    align-items: center;
}

.about-image {
    flex: 1;
}

.about-image img {
    border-radius: 10px;
    box-shadow: var(--box-shadow);
}

.about-text {
    flex: 1;
}

.about-text p {
    margin-bottom: 20px;
    color: var(--gray-color);
}

.skills h3 {
    margin-bottom: 15px;
    font-size: 1.4rem;
    color: var(--dark-color);
}

.skill-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.skill-list li {
    background-color: var(--primary-color);
    color: white;
    padding: 8px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
}

/* Education Section */
.education {
    background-color: #f4f7fb;
}

.timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    height: 100%;
    width: 2px;
    background-color: var(--primary-color);
    left: 50%;
    transform: translateX(-50%);
}

.timeline-item {
    padding: 20px;
    position: relative;
    width: 50%;
    margin-bottom: 30px;
}

.timeline-item:nth-child(odd) {
    left: 0;
}

.timeline-item:nth-child(even) {
    left: 50%;
}

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

.timeline-content::before {
    content: '';
    position: absolute;
    top: 20px;
    width: 20px;
    height: 20px;
    background-color: white;
    border-radius: 50%;
    border: 3px solid var(--primary-color);
}

.timeline-item:nth-child(odd) .timeline-content::before {
    right: -60px;
}

.timeline-item:nth-child(even) .timeline-content::before {
    left: -60px;
}

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

.timeline-content h4 {
    font-weight: normal;
    font-style: italic;
    margin-bottom: 10px;
}

.timeline-date {
    color: var(--gray-color);
    font-size: 0.9rem;
    margin-bottom: 10px;
}

/* Projects Section */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 30px;
}

.project-card {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--box-shadow);
    transition: transform 0.3s ease;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-5px);
}

.project-image {
    height: 220px;
    overflow: hidden;
    position: relative;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    transition: transform 0.5s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-info {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.project-info h3 {
    margin-bottom: 10px;
    color: var(--dark-color);
}

.project-info p {
    color: var(--gray-color);
    margin-bottom: 15px;
    flex: 1;
}

.project-links {
    display: flex;
    gap: 10px;
    margin-top: auto;
}

/* Additional project image fixes */
.project-image::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(to bottom, rgba(0,0,0,0) 60%, rgba(0,0,0,0.5) 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 1;
}

.project-card:hover .project-image::before {
    opacity: 1;
}

/* Fix for image size variations */
@media (max-width: 400px) {
    .project-image {
        height: 180px;
    }
}

/* For browsers that support aspect-ratio */
@supports (aspect-ratio: 16/9) {
    .project-image {
        height: auto;
        aspect-ratio: 16/9;
    }
}

/* Publications Section */
.publication-list {
    max-width: 900px;
    margin: 0 auto;
}

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

.publication-item h3 {
    color: var(--dark-color);
    margin-bottom: 10px;
}

.publication-authors, .publication-journal {
    color: var(--gray-color);
    font-size: 0.95rem;
    margin-bottom: 10px;
}

.publication-abstract {
    margin-bottom: 15px;
}

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

.publication-link {
    display: inline-flex;
    align-items: center;
    padding: 6px 12px;
    background-color: #f8f9fa;
    border-radius: 4px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-color);
    transition: all 0.2s ease;
    border: 1px solid var(--border-color);
}

.publication-link i {
    margin-right: 6px;
}

.publication-link:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    border-color: var(--primary-color);
}

.publication-link:active {
    transform: translateY(0);
}

/* Publication link specific colors */
.publication-link:nth-child(1) { /* PDF */
    color: #e94335;
    border-color: rgba(233, 67, 53, 0.3);
}

.publication-link:nth-child(1):hover {
    background-color: #e94335;
    color: white;
    border-color: #e94335;
}

.publication-link:nth-child(2) { /* DOI */
    color: #4285f4;
    border-color: rgba(66, 133, 244, 0.3);
}

.publication-link:nth-child(2):hover {
    background-color: #4285f4;
    color: white;
    border-color: #4285f4;
}

.publication-link:nth-child(3) { /* GitHub */
    color: #333;
    border-color: rgba(51, 51, 51, 0.3);
}

.publication-link:nth-child(3):hover {
    background-color: #333;
    color: white;
    border-color: #333;
}

/* Interests Section */
.interests {
    background-color: #f4f7fb;
}

.interests-content {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
}

.interest-category {
    background-color: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: var(--box-shadow);
}

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

.interest-category h3 i {
    margin-right: 10px;
}

.interest-category ul li {
    margin-bottom: 10px;
    padding-left: 15px;
    position: relative;
    color: var(--gray-color);
}

.interest-category ul li::before {
    content: "\f054";
    font-family: "Font Awesome 5 Free";
    font-weight: 900;
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-size: 0.7rem;
}

/* Contact Section */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 50px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 15px;
}

.contact-item i {
    width: 40px;
    height: 40px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.contact-item a {
    color: var(--gray-color);
}

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

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

.contact-form input, .contact-form textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-family: var(--font-primary);
}

.contact-form textarea {
    resize: vertical;
}

.contact-form input:focus, .contact-form textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Footer */
footer {
    background-color: var(--dark-color);
    color: white;
    padding: 30px 0;
}

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

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

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: white;
    transition: var(--transition);
}

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

/* Responsive Styles */
@media (max-width: 992px) {
    .about-content {
        flex-direction: column;
    }

    .about-image {
        margin-bottom: 30px;
    }

    .timeline-item {
        width: 100%;
        left: 0;
    }

    .timeline::before {
        left: 30px;
    }

    .timeline-item:nth-child(even) {
        left: 0;
    }

    .timeline-item:nth-child(odd) .timeline-content::before,
    .timeline-item:nth-child(even) .timeline-content::before {
        left: -50px;
    }

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

@media (max-width: 768px) {
    .header-left {
        margin-bottom: 10px;
    }
    
    header .container {
        flex-direction: column;
    }

    header h1 {
        margin-bottom: 5px;
    }

    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }

    nav li {
        margin: 5px 10px;
    }

    .hero {
        padding: 150px 0 80px;
    }

    .hero-content h2 {
        font-size: 2.5rem;
    }

    .hero-content p {
        font-size: 1.2rem;
    }

    .hero-buttons {
        flex-direction: column;
        gap: 15px;
    }

    .interests-content,
    .project-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
}

@media (max-width: 576px) {
    .section-title {
        font-size: 2rem;
    }
}

/* Form validation */
.contact-form input.error,
.contact-form textarea.error {
    border-color: var(--error-color);
    background-color: rgba(234, 67, 53, 0.05);
}

.form-message {
    padding: 12px;
    border-radius: 5px;
    margin-bottom: 20px;
    opacity: 1;
    transition: opacity 0.5s ease;
}

.form-message.error {
    background-color: rgba(234, 67, 53, 0.1);
    color: var(--error-color);
    border: 1px solid var(--error-color);
}

.form-message.success {
    background-color: rgba(52, 168, 83, 0.1);
    color: var(--success-color);
    border: 1px solid var(--success-color);
}

.form-message.fade-out {
    opacity: 0;
}

/* Sticky header */
header.sticky {
    background-color: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

/* Animations */
.section-title,
.about-content,
.project-card,
.publication-item,
.timeline-item,
.interest-category {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.section-title.revealed,
.about-content.revealed,
.project-card.revealed,
.publication-item.revealed,
.timeline-item.revealed,
.interest-category.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* Mobile Navigation */
.mobile-nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--primary-color);
    cursor: pointer;
}

@media (max-width: 768px) {
    .mobile-nav-toggle {
        display: block;
    }
    
    header .container {
        padding: 15px 20px;
    }
    
    nav {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: white;
        padding: 0;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.5s ease;
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
    }
    
    nav.active {
        max-height: 300px;
    }
    
    nav ul {
        flex-direction: column;
        padding: 20px;
    }
    
    nav li {
        margin: 0 0 15px 0;
    }
    
    nav li:last-child {
        margin-bottom: 0;
    }
}

/* Social Icons in Hero */
.social-icons {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 30px;
}

.social-icons a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 45px;
    height: 45px;
    background-color: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    color: white;
    font-size: 1.2rem;
    transition: var(--transition);
    border: 2px solid transparent;
}

.social-icons a:hover {
    background-color: white;
    color: var(--primary-color);
    transform: translateY(-3px);
    border-color: white;
}

/* Research Section */
.research {
    background-color: #f4f7fb;
}

.research-category {
    margin-bottom: 50px;
}

.research-category:last-child {
    margin-bottom: 0;
}

.research-category-title {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--dark-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
    display: inline-flex;
    align-items: center;
}

.research-category-title i {
    margin-right: 12px;
    color: var(--primary-color);
}

/* Certifications Section */
.certifications-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
    gap: 30px;
}

.certification-item {
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--box-shadow);
    overflow: hidden;
    display: flex;
    transition: transform 0.3s ease;
}

.certification-item:hover {
    transform: translateY(-5px);
}

.certification-logo {
    width: 120px;
    min-width: 120px;
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #f5f5f7;
    border-right: 1px solid var(--border-color);
}

.certification-logo img {
    max-width: 100%;
    max-height: 70px;
    object-fit: contain;
}

.certification-content {
    padding: 20px;
    flex: 1;
}

.certification-content h3 {
    font-size: 1.3rem;
    margin-bottom: 8px;
    color: var(--dark-color);
}

.certification-issuer {
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 5px;
    font-size: 0.95rem;
}

.certification-date {
    color: var(--gray-color);
    font-size: 0.85rem;
    margin-bottom: 15px;
}

.certification-description {
    color: var(--gray-color);
    margin-bottom: 15px;
    font-size: 0.95rem;
}

.certification-link {
    display: inline-flex;
    align-items: center;
    padding: 6px 12px;
    background-color: #f8f9fa;
    border-radius: 4px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--primary-color);
    transition: all 0.2s ease;
    border: 1px solid rgba(66, 133, 244, 0.3);
}

.certification-link i {
    margin-right: 6px;
}

.certification-link:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    border-color: var(--primary-color);
}

/* Responsive adjustments for certifications */
@media (max-width: 768px) {
    .certifications-container {
        grid-template-columns: 1fr;
    }
}

.project-summary {
    font-size: 0.95rem;
    margin-bottom: 10px;
}

.project-role {
    font-size: 0.9rem;
    color: var(--primary-color);
    font-style: italic;
    margin-bottom: 15px;
}

.btn-details {
    background-color: #f8f9fa;
    color: var(--dark-color);
    border: 1px solid var(--border-color);
}

.btn-details:hover {
    background-color: var(--gray-color);
    border-color: var(--gray-color);
    color: white;
}

/* Project Modals */
.project-modal {
    display: none;
    position: fixed;
    z-index: 1100;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.7);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-modal.active {
    display: block;
    opacity: 1;
}

.project-modal-content {
    background-color: #fff;
    margin: 10% auto;
    padding: 30px;
    border-radius: 8px;
    width: 70%;
    max-width: 800px;
    box-shadow: 0 5px 30px rgba(0, 0, 0, 0.3);
    position: relative;
    transform: translateY(-30px);
    transition: transform 0.3s ease;
}

.project-modal.active .project-modal-content {
    transform: translateY(0);
}

.project-modal-close {
    position: absolute;
    top: 15px;
    right: 20px;
    font-size: 28px;
    color: var(--gray-color);
    cursor: pointer;
    transition: color 0.2s ease;
}

.project-modal-close:hover {
    color: var(--primary-color);
}

.project-modal h2 {
    margin-bottom: 20px;
    color: var(--primary-color);
    font-size: 1.8rem;
}

.project-modal-body {
    color: var(--gray-color);
}

.project-modal-body p {
    margin-bottom: 15px;
    line-height: 1.6;
}

.project-modal-links {
    margin-top: 25px;
}

/* Modal Responsive Styles */
@media (max-width: 768px) {
    .project-modal-content {
        width: 85%;
        margin: 15% auto;
        padding: 20px;
    }
}

/* Certification List Styling */
.certification-list {
    margin: 15px 0;
    padding-left: 10px;
}

.certification-list li {
    margin-bottom: 8px;
    position: relative;
    padding-left: 28px;
    line-height: 1.5;
}

.certification-list li i {
    position: absolute;
    left: 0;
    top: 3px;
    color: var(--primary-color);
    font-size: 1rem;
}