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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #2d3748;
    background-color: #ffffff;
    scroll-behavior: smooth;
}

/* CSS Variables for Color System */
:root {
    --primary-50: #eff6ff;
    --primary-100: #dbeafe;
    --primary-500: #3b82f6;
    --primary-600: #2563eb;
    --primary-700: #1d4ed8;
    --primary-800: #1e40af;
    --primary-900: #1e3a8a;
    
    --secondary-50: #ecfeff;
    --secondary-100: #cffafe;
    --secondary-500: #06b6d4;
    --secondary-600: #0891b2;
    --secondary-700: #0e7490;
    
    --accent-50: #fff7ed;
    --accent-100: #ffedd5;
    --accent-500: #f97316;
    --accent-600: #ea580c;
    --accent-700: #c2410c;
    
    --neutral-50: #f9fafb;
    --neutral-100: #f3f4f6;
    --neutral-200: #e5e7eb;
    --neutral-300: #d1d5db;
    --neutral-400: #9ca3af;
    --neutral-500: #6b7280;
    --neutral-600: #4b5563;
    --neutral-700: #374151;
    --neutral-800: #1f2937;
    --neutral-900: #111827;
    
    --success-500: #10b981;
    --warning-500: #f59e0b;
    --error-500: #ef4444;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--neutral-200);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.nav-logo span {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-800);
}

.nav-menu {
    display: flex;
    gap: 32px;
}

.nav-link {
    text-decoration: none;
    color: var(--neutral-600);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--primary-600);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-600);
    transition: width 0.3s ease;
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 24px;
    height: 3px;
    background: var(--neutral-600);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--primary-50) 0%, var(--secondary-50) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.hero-content {
    animation: fadeInUp 0.8s ease;
}

.hero-greeting {
    display: block;
    font-size: 1.25rem;
    color: var(--neutral-600);
    margin-bottom: 8px;
}

.hero-name {
    display: block;
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--primary-800);
    line-height: 1.1;
    margin-bottom: 16px;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--secondary-600);
    font-weight: 600;
    margin-bottom: 24px;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--neutral-600);
    line-height: 1.7;
    margin-bottom: 40px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 40px;
}

.btn {
    display: inline-flex;
    align-items: center;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--primary-600);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-700);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: transparent;
    color: var(--primary-600);
    border-color: var(--primary-600);
}

.btn-secondary:hover {
    background: var(--primary-600);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.hero-social {
    display: flex;
    gap: 16px;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: white;
    border-radius: 50%;
    color: var(--neutral-600);
    text-decoration: none;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

.social-link:hover {
    color: var(--primary-600);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Hero Visual */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-graphic {
    position: relative;
    width: 400px;
    height: 400px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 24px;
}

.floating-card {
    background: white;
    padding: 16px 20px;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    color: var(--neutral-700);
    animation: float 3s ease-in-out infinite;
    width: 280px;
    justify-content: center;
}

.floating-card:nth-child(1) {
    animation-delay: 0s;
}

.floating-card:nth-child(2) {
    animation-delay: 1s;
}

.floating-card:nth-child(3) {
    animation-delay: 2s;
}

.floating-card i {
    font-size: 1.5rem;
    color: var(--primary-600);
}

/* Section Styles */
section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--neutral-800);
    margin-bottom: 64px;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -16px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-600), var(--secondary-600));
    border-radius: 2px;
}

/* About Section */
.about {
    background: var(--neutral-50);
}

.about-content {
    display: grid;
    grid-template-columns: 300px 2fr 1fr;
    gap: 48px;
    align-items: start;
}

.about-photo {
    display: flex;
    justify-content: center;
    align-items: flex-start;
}

.photo-container {
    position: relative;
    width: 280px;
    height: 350px;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    transition: transform 0.3s ease;
}

.photo-container:hover {
    transform: translateY(-8px);
}

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

.photo-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(6, 182, 212, 0.1));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.photo-container:hover .photo-overlay {
    opacity: 1;
}

.about-description {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--neutral-600);
    margin-bottom: 24px;
}

.about-highlights {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 32px;
}

.highlight-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    color: var(--neutral-700);
}

.highlight-item i {
    color: var(--primary-600);
    font-size: 1.25rem;
}

.about-stats {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.stat-card {
    background: white;
    padding: 32px 24px;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-4px);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-600);
    margin-bottom: 8px;
}

.stat-label {
    color: var(--neutral-600);
    font-weight: 500;
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.skill-category {
    background: white;
    padding: 32px;
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.skill-category:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.category-title {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--neutral-800);
    margin-bottom: 24px;
}

.category-title i {
    color: var(--primary-600);
    font-size: 1.5rem;
}

.skill-items {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.skill-tag {
    background: var(--primary-100);
    color: var(--primary-700);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.skill-tag:hover {
    background: var(--primary-600);
    color: white;
}

/* Education Section */
.education {
    background: var(--neutral-50);
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: calc(100% - 32px);
    background: linear-gradient(to bottom, var(--primary-600), var(--secondary-600));
    top: 16px;
    border-radius: 1px;
}

.timeline-item {
    display: flex;
    justify-content: flex-end;
    padding-right: 50%;
    position: relative;
    margin-bottom: 48px;
}

.timeline-item:nth-child(even) {
    justify-content: flex-start;
    padding-left: 50%;
    padding-right: 0;
}

.timeline-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    background: var(--primary-600);
    border: 3px solid white;
    border-radius: 50%;
    box-shadow: var(--shadow-md);
    z-index: 2;
}

.timeline-content {
    background: white;
    padding: 24px;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    max-width: 400px;
    margin-right: 24px;
}

.timeline-item:nth-child(even) .timeline-content {
    margin-left: 24px;
    margin-right: 0;
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 8px;
}

.timeline-header h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--neutral-800);
    flex: 1;
}

.timeline-date {
    background: var(--primary-100);
    color: var(--primary-700);
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 500;
    white-space: nowrap;
    margin-left: 16px;
}

.timeline-institution {
    color: var(--secondary-600);
    font-weight: 600;
    margin-bottom: 12px;
}

.timeline-description {
    color: var(--neutral-600);
    line-height: 1.6;
}

.timeline-courses {
    margin-top: 16px;
}

.timeline-courses h5 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--neutral-700);
    margin-bottom: 12px;
}

.course-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.course-tag {
    background: var(--primary-100);
    color: var(--primary-700);
    padding: 6px 12px;
    border-radius: 16px;
    font-size: 0.8rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.course-tag:hover {
    background: var(--primary-600);
    color: white;
    transform: translateY(-1px);
}

/* Experience Section */
.experience {
    background: white;
}

.experience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 32px;
}

.experience-card {
    background: white;
    border-radius: 16px;
    padding: 32px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border: 1px solid var(--neutral-200);
}

.experience-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.experience-header {
    margin-bottom: 24px;
}

.experience-company {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
}

.company-name {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-600);
}

.experience-period {
    background: var(--accent-100);
    color: var(--accent-700);
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 500;
}

.experience-role h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--neutral-800);
    margin-bottom: 4px;
}

.experience-location {
    color: var(--neutral-500);
    font-size: 0.875rem;
}

.experience-description {
    margin-bottom: 24px;
}

.experience-description ul {
    list-style: none;
    padding: 0;
}

.experience-description li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: var(--neutral-600);
    line-height: 1.6;
}

.experience-description li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary-600);
    font-weight: bold;
}

.experience-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tech-tag {
    background: var(--secondary-100);
    color: var(--secondary-700);
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 500;
}

/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 32px;
}

.project-card {
    background: white;
    border-radius: 16px;
    padding: 32px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border: 1px solid var(--neutral-200);
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 16px;
}

.project-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--neutral-800);
    flex: 1;
}

.project-links {
    display: flex;
    gap: 8px;
}

.project-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--neutral-100);
    border-radius: 8px;
    color: var(--neutral-600);
    text-decoration: none;
    transition: all 0.3s ease;
}

.project-link:hover {
    background: var(--primary-600);
    color: white;
}

.project-description {
    color: var(--neutral-600);
    line-height: 1.6;
    margin-bottom: 24px;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

/* Publications Section */
.publications {
    background: var(--neutral-50);
}

.publications-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.publication-item {
    background: white;
    padding: 32px;
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.publication-item:hover {
    transform: translateY(-4px);
}

.publication-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--neutral-800);
    margin-bottom: 16px;
}

.publication-authors {
    font-size: 0.95rem;
    color: var(--neutral-600);
    margin-bottom: 8px;
    font-style: italic;
}

.publication-venue {
    font-size: 0.9rem;
    color: var(--primary-600);
    font-weight: 500;
    margin-bottom: 12px;
}

.publication-description {
    color: var(--neutral-600);
    line-height: 1.6;
    margin-bottom: 24px;
}

.publication-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--primary-600);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.publication-link:hover {
    color: var(--primary-700);
}

/* Contact Section */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: start;
}

.contact-info h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--neutral-800);
    margin-bottom: 16px;
}

.contact-description {
    color: var(--neutral-600);
    line-height: 1.6;
    margin-bottom: 32px;
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.contact-method {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: white;
    border-radius: 12px;
    color: var(--neutral-700);
    text-decoration: none;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
}

.contact-method:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(4px);
}

.contact-method i {
    color: var(--primary-600);
    font-size: 1.25rem;
}

.cta-card {
    background: linear-gradient(135deg, var(--primary-600), var(--secondary-600));
    padding: 40px;
    border-radius: 16px;
    text-align: center;
    color: white;
}

.cta-card h4 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.cta-card p {
    margin-bottom: 24px;
    opacity: 0.9;
}

.cta-card .btn-primary {
    background: white;
    color: var(--primary-600);
}

.cta-card .btn-primary:hover {
    background: var(--neutral-100);
}

/* Footer */
.footer {
    background: var(--neutral-800);
    color: var(--neutral-300);
    padding: 32px 0;
}

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

.footer-links {
    display: flex;
    gap: 24px;
}

.footer-links a {
    color: var(--neutral-300);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 48px;
        text-align: center;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: 32px;
        text-align: center;
    }
    
    .about-photo {
        order: -1;
        justify-content: center;
    }
    
    .photo-container {
        width: 250px;
        height: 300px;
    }
    
    .about-text {
        gap: 48px;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 48px;
    }
    
    .timeline::before {
        left: 24px;
    }
    
    .timeline-item {
        justify-content: flex-start !important;
        padding-left: 56px !important;
        padding-right: 0 !important;
    }
    
    .timeline-marker {
        left: 24px !important;
        transform: translateX(-50%);
    }
    
    .timeline-content {
        margin-left: 0 !important;
        margin-right: 0 !important;
    }

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

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 64px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-lg);
        padding: 24px 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-name {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-graphic {
        width: 300px;
        height: auto;
    }
    
    .floating-card {
        font-size: 0.875rem;
        padding: 12px 16px;
        width: 240px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .photo-container {
        width: 220px;
        height: 280px;
    }
    
    .about-stats {
        flex-direction: row;
        justify-content: center;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .timeline-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }
    
    .timeline-date {
        margin-left: 0;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }
    
    .nav-container {
        padding: 0 16px;
    }
    
    .hero {
        padding: 100px 0 60px;
    }
    
    .hero-name {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    section {
        padding: 60px 0;
    }
    
    .photo-container {
        width: 200px;
        height: 250px;
    }
    
    .about-stats {
        flex-direction: column;
    }
    
    .floating-card {
        width: 200px;
        font-size: 0.8rem;
        padding: 10px 14px;
    }
    
    .hero-graphic {
        width: 100%;
        height: auto;
    }
}