/* ============================================
   Modern CSS Variables & Reset
   ============================================ */

:root {
    /* Colors - Green Aesthetic Theme */
    --primary: #10b981;
    --primary-dark: #059669;
    --primary-light: #34d399;
    --secondary: #14b8a6;
    --accent: #6ee7b7;
    
    --bg-primary: #0a1612;
    --bg-secondary: #0f2419;
    --bg-tertiary: #1a3d2e;
    --bg-card: rgba(15, 36, 25, 0.6);
    
    --text-primary: #f0fdf4;
    --text-secondary: #d1fae5;
    --text-muted: #a7f3d0;
    
    --border: rgba(16, 185, 129, 0.2);
    --shadow: rgba(16, 185, 129, 0.15);
    --glow: rgba(16, 185, 129, 0.4);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;
    
    /* Transitions */
    --transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    background-image: 
        radial-gradient(at 0% 0%, rgba(16, 185, 129, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 0%, rgba(20, 184, 166, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(110, 231, 183, 0.1) 0px, transparent 50%);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.75rem); }

.lead {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--text-secondary);
}

/* ============================================
   Container & Layout
   ============================================ */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

section {
    padding: var(--spacing-xl) 0;
}

/* ============================================
   Navigation
   ============================================ */

.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(15, 36, 25, 0.6);
    backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 4px 30px rgba(16, 185, 129, 0.1);
    z-index: 1000;
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem var(--spacing-md);
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
}

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

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

/* ============================================
   Hero Section
   ============================================ */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    background: 
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 50%, rgba(20, 184, 166, 0.1) 0%, transparent 50%),
        var(--bg-primary);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.hero-image {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
}

.profile-img {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    border: 4px solid var(--primary);
    box-shadow: 
        0 0 60px rgba(16, 185, 129, 0.3),
        0 0 100px rgba(16, 185, 129, 0.2),
        0 20px 60px rgba(0, 0, 0, 0.3);
    object-fit: cover;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

.status-badge {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 50px;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.status-dot {
    width: 8px;
    height: 8px;
    background: var(--secondary);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.hero-text {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.hero-title {
    margin-bottom: var(--spacing-sm);
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.hero-description {
    color: var(--text-muted);
    font-size: 1.125rem;
    max-width: 600px;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    padding: var(--spacing-md) 0;
}

.stat {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* ============================================
   Buttons
   ============================================ */

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 
        0 0 30px rgba(16, 185, 129, 0.5),
        0 10px 40px rgba(16, 185, 129, 0.3);
    background: linear-gradient(135deg, var(--primary-light), var(--primary));
}

.btn-secondary {
    background: var(--bg-card);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

/* ============================================
   Social Links
   ============================================ */

.social-links {
    display: flex;
    gap: var(--spacing-sm);
}

.social-links a {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 50%;
    color: var(--text-secondary);
    font-size: 1.25rem;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.4);
}

/* ============================================
   Section Title
   ============================================ */

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    position: relative;
    padding-bottom: var(--spacing-sm);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary), var(--primary), var(--accent));
    border-radius: 2px;
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.6);
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
}

/* ============================================
   About Section
   ============================================ */

.about {
    background: var(--bg-secondary);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.about-text {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.about-text p {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

.impact-metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.metric-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    transition: var(--transition);
}

.metric-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--shadow);
}

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

.metric-card p {
    margin: 0;
    color: var(--text-secondary);
}

/* ============================================
   Research Section
   ============================================ */

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.research-card {
    padding: var(--spacing-lg);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: 20px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.research-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(20, 184, 166, 0.1));
    opacity: 0;
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-10px);
    box-shadow: 
        0 0 40px rgba(16, 185, 129, 0.3),
        0 20px 60px rgba(0, 0, 0, 0.3);
    border-color: var(--primary);
}

.research-card:hover::before {
    opacity: 1;
}

.card-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 16px;
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
    box-shadow: 0 0 30px rgba(16, 185, 129, 0.4);
    position: relative;
    z-index: 1;
}

.research-card h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.research-card ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.research-card li {
    color: var(--text-secondary);
    padding-left: 1.5rem;
    position: relative;
}

.research-card li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--primary);
}

/* ============================================
   Skills Section
   ============================================ */

.skills {
    background: var(--bg-secondary);
}

.experience {
    background: var(--bg-secondary);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.skill-category {
    padding: var(--spacing-lg);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    transition: var(--transition);
}

.skill-category:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--shadow);
}

.skill-category h3 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

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

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tag {
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: var(--transition);
}

.tag:hover {
    background: var(--primary);
    color: white;
    transform: scale(1.05);
}

/* ============================================
   Experience Section - Timeline
   ============================================ */

.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-md) 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, var(--primary), var(--secondary));
}

.timeline-item {
    position: relative;
    padding-left: 60px;
    margin-bottom: var(--spacing-lg);
}

.timeline-marker {
    position: absolute;
    left: 11px;
    top: 0;
    width: 20px;
    height: 20px;
    background: var(--primary);
    border: 3px solid var(--bg-secondary);
    border-radius: 50%;
    z-index: 1;
}

.timeline-content {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: var(--spacing-lg);
    transition: var(--transition);
}

.timeline-content:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 30px var(--shadow);
    border-color: var(--primary);
}

.timeline-header {
    margin-bottom: var(--spacing-md);
}

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

.timeline-company {
    display: inline-block;
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--primary);
    margin-right: var(--spacing-sm);
}

.timeline-date {
    display: inline-block;
    font-size: 0.875rem;
    color: var(--text-muted);
    padding: 0.25rem 0.75rem;
    background: var(--bg-tertiary);
    border-radius: 20px;
}

.timeline-details {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.timeline-details li {
    color: var(--text-secondary);
    padding-left: 1.5rem;
    position: relative;
}

.timeline-details li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--secondary);
    font-weight: bold;
}

/* ============================================
   Projects Section
   ============================================ */

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: var(--spacing-lg);
}

.project-card {
    padding: var(--spacing-lg);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: 20px;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    position: relative;
    overflow: hidden;
}

.project-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(
        45deg,
        transparent,
        rgba(16, 185, 129, 0.1),
        transparent
    );
    transform: rotate(45deg);
    opacity: 0;
    transition: var(--transition);
}

.project-card:hover {
    transform: translateY(-15px) scale(1.02);
    box-shadow: 
        0 0 60px rgba(16, 185, 129, 0.4),
        0 25px 80px rgba(0, 0, 0, 0.4);
    border-color: var(--primary);
}

.project-card:hover::before {
    opacity: 1;
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%) translateY(-100%) rotate(45deg);
    }
    100% {
        transform: translateX(100%) translateY(100%) rotate(45deg);
    }
}

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

.project-icon {
    font-size: 3rem;
}

.project-links {
    display: flex;
    gap: var(--spacing-sm);
}

.project-links a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border-radius: 8px;
    color: var(--text-secondary);
    transition: var(--transition);
}

.project-links a:hover {
    background: var(--primary);
    color: white;
    transform: scale(1.1);
}

.project-card h3 {
    color: var(--text-primary);
}

.project-tagline {
    color: var(--primary);
    font-style: italic;
    font-size: 1rem;
}

.project-description {
    color: var(--text-secondary);
    line-height: 1.7;
}

.project-features {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.feature {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-secondary);
}

.feature i {
    color: var(--secondary);
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border);
}

.tech-tag {
    padding: 0.375rem 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--primary);
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--primary);
}

/* ============================================
   Publications Section
   ============================================ */

.publications {
    background: var(--bg-secondary);
}

.publications .section-subtitle {
    text-align: center;
}

.publications-list {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.publication-category h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--border);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

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

.publication-item {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    margin-bottom: var(--spacing-md);
    transition: var(--transition);
}

.publication-item:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 30px var(--shadow);
    border-color: var(--primary);
}

.pub-year {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-align: center;
    padding-top: 0.25rem;
}

.pub-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.pub-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.4;
    margin: 0;
}

.pub-authors {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin: 0;
}

.pub-venue {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin: 0;
}

.pub-status {
    display: inline-block;
    padding: 0.125rem 0.5rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--primary);
    border-radius: 12px;
    color: var(--primary);
    font-size: 0.85rem;
    font-weight: 500;
}

.pub-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    margin-top: 0.5rem;
    background: var(--primary);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
}

.pub-link:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(99, 102, 241, 0.4);
}

.pub-link i {
    font-size: 0.85rem;
}

.link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

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

/* ============================================
   Contact Section
   ============================================ */

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.contact-card {
    padding: var(--spacing-lg);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    text-align: center;
    transition: var(--transition);
}

.contact-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px var(--shadow);
    border-color: var(--primary);
}

.contact-card i {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: var(--spacing-sm);
}

.contact-card h3 {
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

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

.contact-cta {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.contact-social {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    justify-content: center;
}

.social-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.75rem 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.social-btn:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transform: translateY(-2px);
}

/* ============================================
   Footer
   ============================================ */

.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: var(--spacing-md) 0;
    text-align: center;
    color: var(--text-muted);
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-image {
        order: -1;
    }
    
    .hero-text {
        align-items: center;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .hero-stats {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-stats {
        grid-template-columns: 1fr;
    }
    
    .profile-img {
        width: 200px;
        height: 200px;
    }
    
    section {
        padding: var(--spacing-lg) 0;
    }
}

@media (max-width: 480px) {
    .hero-cta {
        flex-direction: column;
        width: 100%;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .social-links {
        justify-content: center;
    }
    
    .publication-item {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .pub-year {
        text-align: left;
    }
    
    .timeline::before {
        left: 10px;
    }
    
    .timeline-item {
        padding-left: 40px;
    }
    
    .timeline-marker {
        left: 1px;
    }
}