/* ================================================
   Jialu Yao - Personal Website Styles
   Modern Light Gradient Theme
   ================================================ */

/* CSS Variables */
:root {
    /* Colors - Clean Blue-Teal Theme */
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --bg-card: #ffffff;
    --bg-card-hover: #ffffff;
    
    /* Gradient Colors - Fresh Blue-Teal */
    --gradient-1: #0ea5e9;
    --gradient-2: #06b6d4;
    --gradient-3: #14b8a6;
    --gradient-4: #10b981;
    --accent-primary: #0ea5e9;
    --accent-secondary: #06b6d4;
    --accent-tertiary: #14b8a6;
    --gradient-main: linear-gradient(135deg, #0ea5e9 0%, #06b6d4 50%, #14b8a6 100%);
    --gradient-accent: linear-gradient(135deg, #0ea5e9 0%, #06b6d4 100%);
    --gradient-warm: linear-gradient(135deg, #14b8a6 0%, #10b981 100%);
    --gradient-soft: linear-gradient(135deg, rgba(14, 165, 233, 0.06), rgba(20, 184, 166, 0.06));
    
    /* Glass Effect - Light Version */
    --glass: rgba(255, 255, 255, 0.8);
    --glass-border: rgba(14, 165, 233, 0.12);
    
    /* Text Colors - Dark for Light Theme */
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    /* Spacing */
    --section-padding: 120px;
    --container-width: 1200px;
    
    /* Typography */
    --font-primary: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Effects */
    --shadow-sm: 0 2px 8px rgba(14, 165, 233, 0.06);
    --shadow-md: 0 4px 20px rgba(14, 165, 233, 0.10);
    --shadow-lg: 0 10px 40px rgba(14, 165, 233, 0.12);
    --shadow-glow: 0 0 60px rgba(14, 165, 233, 0.20);
    --transition-fast: 0.2s ease;
    --transition-medium: 0.4s ease;
    --border-radius: 20px;
}

/* Reset & Base */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
}

/* Selection */
::selection {
    background: var(--accent-primary);
    color: white;
}

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

/* ================================================
   Navigation
   ================================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    background: rgba(26, 26, 46, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition-medium);
}

.navbar.scrolled {
    background: rgba(26, 26, 46, 0.98);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

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

.nav-logo {
    font-size: 1.2rem;
    font-weight: 700;
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    letter-spacing: -0.01em;
    transition: color 0.3s ease;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 8px;
}

.nav-menu a {
    color: rgba(255, 255, 255, 0.85);
    text-decoration: none;
    padding: 10px 18px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition-fast);
    position: relative;
}

.nav-menu a:hover {
    color: rgba(255, 255, 255, 0.95);
    background: rgba(255, 255, 255, 0.08);
}

/* Social Links in Nav */
.nav-social {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-left: 20px;
    padding-left: 20px;
    border-left: 1px solid rgba(255, 255, 255, 0.2);
}

.nav-social a {
    color: rgba(255, 255, 255, 0.7);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-social a:hover {
    color: rgba(255, 255, 255, 0.95);
    transform: translateY(-2px);
}

.nav-social svg {
    width: 20px;
    height: 20px;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: 6px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 20px;
    height: 2px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 2px;
    transition: transform var(--transition-fast);
}

.nav-menu a:hover::after {
    transform: translateX(-50%) scaleX(1);
}

/* Hamburger Menu */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 10px;
}

.hamburger span {
    width: 24px;
    height: 2px;
    background: rgba(255, 255, 255, 0.85);
    border-radius: 2px;
    transition: var(--transition-fast);
}

/* ================================================
   Hero Section
   ================================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 80px 24px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.grid-overlay {
    position: absolute;
    inset: 0;
    background-image: 
        linear-gradient(rgba(102, 126, 234, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(102, 126, 234, 0.05) 1px, transparent 1px);
    background-size: 60px 60px;
    mask-image: radial-gradient(ellipse at center, black 20%, transparent 70%);
}

.glow {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.4;
    animation: float 20s ease-in-out infinite;
}

.glow-1 {
    width: 700px;
    height: 700px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    top: -300px;
    right: -200px;
    animation-delay: 0s;
}

.glow-2 {
    width: 600px;
    height: 600px;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    bottom: -250px;
    left: -200px;
    animation-delay: -7s;
}

.glow-3 {
    width: 500px;
    height: 500px;
    background: linear-gradient(135deg, #a78bfa 0%, #818cf8 100%);
    top: 30%;
    left: 50%;
    opacity: 0.3;
    animation-delay: -14s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(30px, -30px) scale(1.05); }
    50% { transform: translate(-20px, 20px) scale(0.95); }
    75% { transform: translate(20px, 30px) scale(1.02); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 24px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: 100px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--accent-primary);
    margin-bottom: 32px;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.2s;
    opacity: 0;
    box-shadow: var(--shadow-sm);
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: #10b981;
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
    box-shadow: 0 0 10px rgba(16, 185, 129, 0.5);
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.2); }
}

.hero-title {
    margin-bottom: 24px;
}

.greeting {
    display: block;
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text-secondary);
    margin-bottom: 8px;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.4s;
    opacity: 0;
}

.name {
    display: block;
    font-size: clamp(3rem, 8vw, 5.5rem);
    font-weight: 700;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.03em;
    line-height: 1.1;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.5s;
    opacity: 0;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 40px;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.6s;
    opacity: 0;
}

.highlight {
    color: var(--accent-primary);
    font-weight: 600;
}

.hero-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 60px;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.7s;
    opacity: 0;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    border-radius: 12px;
    font-family: var(--font-primary);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition-fast);
    border: none;
}

.btn-primary {
    background: var(--gradient-main);
    color: white;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.45);
}

.btn-secondary {
    background: white;
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

/* Hero Stats */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.8s;
    opacity: 0;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* Scroll Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    color: var(--text-muted);
    font-size: 0.8rem;
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 1s;
    opacity: 0;
}

.mouse {
    width: 26px;
    height: 40px;
    border: 2px solid var(--glass-border);
    border-radius: 20px;
    display: flex;
    justify-content: center;
    padding-top: 8px;
}

.wheel {
    width: 4px;
    height: 8px;
    background: var(--accent-primary);
    border-radius: 4px;
    animation: scroll 2s ease-in-out infinite;
}

@keyframes scroll {
    0%, 100% { transform: translateY(0); opacity: 1; }
    50% { transform: translateY(10px); opacity: 0.3; }
}

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

/* ================================================
   Sections Common
   ================================================ */
.section {
    padding: var(--section-padding) 0;
    position: relative;
}

.section-header {
    margin-bottom: 60px;
    position: relative;
}

/* Section tag removed - styles moved to title */

.section-title {
    font-size: clamp(2rem, 5vw, 2.8rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    position: relative;
    display: inline-block;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: all 0.4s ease;
    cursor: default;
}

.section-title::before {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 40px;
    height: 3px;
    background: var(--gradient-main);
    border-radius: 3px;
    transition: width 0.4s ease;
}

.section-title:hover::before {
    width: 100%;
}

.section-title::after {
    content: '';
    position: absolute;
    top: 50%;
    left: -20px;
    width: 8px;
    height: 8px;
    background: var(--accent-primary);
    border-radius: 50%;
    transform: translateY(-50%);
    opacity: 0;
    transition: all 0.3s ease;
}

.section-header:hover .section-title::after {
    opacity: 1;
    left: -16px;
}

/* ================================================
   About Section
   ================================================ */
.about {
    background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    padding-top: 160px; /* Extra padding since hero is hidden */
}

.about-content {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 80px;
    align-items: center;
}

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

.about-text .lead {
    font-size: 1.2rem;
    color: var(--text-primary);
}

.about-text strong {
    color: var(--accent-primary);
}

.about-text em {
    color: var(--accent-secondary);
    font-style: normal;
}

.about-interests {
    margin-top: 40px;
}

.about-interests h3 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.interest-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    list-style: none;
}

.interest-tags li {
    padding: 8px 16px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: 100px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.interest-tags li:hover {
    border-color: var(--accent-primary);
    transform: translateY(-2px);
    color: var(--accent-primary);
    background: var(--gradient-soft);
}

.about-image {
    position: relative;
}

.image-frame {
    position: relative;
    aspect-ratio: 1;
    max-width: 350px;
    margin: 0 auto;
    border-radius: var(--border-radius);
    background: white;
    border: 1px solid var(--glass-border);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.profile-photo {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center 15%;
}

.placeholder-avatar {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

.placeholder-avatar span {
    font-size: 6rem;
    font-weight: 700;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.floating-card {
    position: absolute;
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 20px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: 14px;
    box-shadow: var(--shadow-md);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    animation: floatCard 6s ease-in-out infinite;
}

.card-1 {
    top: 20px;
    right: -30px;
    animation-delay: 0s;
}

.card-2 {
    bottom: 40px;
    left: -40px;
    animation-delay: -3s;
}

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

.floating-card .icon {
    font-size: 1.2rem;
}

/* ================================================
   Education Timeline
   ================================================ */
.education {
    background: var(--bg-secondary);
}

.timeline {
    position: relative;
    padding-left: 40px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--gradient-main);
}

.timeline-item {
    position: relative;
    padding-bottom: 50px;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: -40px;
    top: 5px;
    width: 16px;
    height: 16px;
    background: white;
    border: 3px solid var(--accent-primary);
    border-radius: 50%;
    box-shadow: 0 0 15px rgba(102, 126, 234, 0.4);
}

.timeline-content {
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: 28px 32px;
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.timeline-content:hover {
    border-color: var(--accent-primary);
    transform: translateX(8px);
    box-shadow: var(--shadow-md);
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 16px;
}

.timeline-header h3 {
    font-size: 1.3rem;
    font-weight: 600;
}

.timeline-date {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--accent-primary);
    background: var(--gradient-soft);
    padding: 4px 12px;
    border-radius: 6px;
}

.timeline-body .degree {
    font-size: 1.05rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.timeline-body .location,
.timeline-body .advisor {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.gpa-badge {
    display: inline-block;
    padding: 4px 12px;
    background: linear-gradient(135deg, rgba(6, 182, 212, 0.2), rgba(139, 92, 246, 0.2));
    border: 1px solid rgba(6, 182, 212, 0.3);
    border-radius: 6px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--accent-primary);
}

.awards {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 16px;
}

.award-tag {
    padding: 6px 14px;
    background: rgba(236, 72, 153, 0.1);
    border: 1px solid rgba(236, 72, 153, 0.2);
    border-radius: 100px;
    font-size: 0.8rem;
    color: var(--accent-tertiary);
}

/* ================================================
   Publications Section
   ================================================ */
.publications {
    background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

.publication-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.publication-card {
    display: flex;
    gap: 24px;
    padding: 28px 32px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.publication-card:hover {
    border-color: var(--accent-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.publication-card.featured {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05), rgba(240, 147, 251, 0.05));
    border-color: rgba(102, 126, 234, 0.3);
}

.publication-year {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-primary);
    min-width: 70px;
}

.publication-content {
    flex: 1;
}

.publication-venue {
    display: inline-block;
    padding: 4px 12px;
    background: var(--gradient-soft);
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--accent-secondary);
    margin-bottom: 12px;
}

.publication-content h3 {
    font-size: 1.1rem;
    font-weight: 600;
    line-height: 1.5;
    margin-bottom: 10px;
}

.publication-authors {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.publication-authors strong {
    color: var(--accent-primary);
}

/* ================================================
   Research Section
   ================================================ */
.research {
    background: var(--bg-primary);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.research-card {
    padding: 32px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.research-card:hover {
    border-color: var(--accent-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.research-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.research-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: 16px;
}

.research-date,
.research-location {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.research-date {
    color: var(--accent-primary);
}

.research-card h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 12px;
    line-height: 1.4;
}

.research-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.6;
}

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

.research-tags span {
    padding: 6px 12px;
    background: var(--gradient-soft);
    border: 1px solid var(--glass-border);
    border-radius: 6px;
    font-size: 0.75rem;
    color: var(--accent-secondary);
}

/* ================================================
   Skills Section
   ================================================ */
.skills {
    background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

.skills-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.skill-category h3 {
    font-size: 1.2rem;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.skill-items {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.skill-item {
    display: flex;
    align-items: center;
    gap: 16px;
}

.skill-name {
    min-width: 100px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.skill-bar {
    flex: 1;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    width: var(--progress);
    background: var(--gradient-main);
    border-radius: 4px;
    transition: width 1s ease;
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.tool-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    font-size: 0.9rem;
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.tool-item:hover {
    border-color: var(--accent-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.tool-icon {
    font-size: 1.2rem;
}

/* ================================================
   Contact Section
   ================================================ */
.contact {
    background: var(--bg-secondary);
}

.contact-content {
    text-align: center;
}

.contact-text {
    max-width: 600px;
    margin: 0 auto 50px;
}

.contact-lead {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 16px;
}

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

.contact-cards {
    display: flex;
    justify-content: center;
    gap: 24px;
    flex-wrap: wrap;
}

.contact-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 32px 40px;
    background: white;
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    text-decoration: none;
    color: inherit;
    min-width: 200px;
    transition: var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.contact-card:hover {
    border-color: var(--accent-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.contact-icon {
    font-size: 2rem;
}

.contact-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.contact-value {
    font-size: 0.95rem;
    color: var(--text-primary);
}

/* ================================================
   Footer
   ================================================ */
.footer {
    background: var(--bg-secondary);
    padding: 60px 0 30px;
    border-top: 1px solid var(--glass-border);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 16px;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-brand p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

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

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition-fast);
}

.footer-links a:hover {
    color: var(--accent-primary);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--glass-border);
}

.footer-bottom p {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ================================================
   Responsive Design
   ================================================ */
@media (max-width: 1024px) {
    .about-content {
        grid-template-columns: 1fr;
        gap: 60px;
    }
    
    .about-image {
        order: -1;
    }
    
    .research-grid {
        grid-template-columns: 1fr;
    }
    
    .skills-container {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 80px;
    }
    
    /* Hide social links on mobile nav */
    .nav-social {
        display: none;
    }
    
    /* Mobile Navigation */
    .nav-menu {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: white;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 20px;
        transform: translateX(100%);
        transition: transform var(--transition-medium);
    }
    
    .nav-menu.active {
        transform: translateX(0);
    }
    
    .nav-menu a {
        font-size: 1.2rem;
    }
    
    .hamburger {
        display: flex;
        z-index: 1001;
    }
    
    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }
    
    /* Hero Responsive */
    .hero-stats {
        gap: 30px;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    /* Timeline Responsive */
    .timeline {
        padding-left: 30px;
    }
    
    .timeline-marker {
        left: -30px;
    }
    
    .timeline-content {
        padding: 20px;
    }
    
    .timeline-header {
        flex-direction: column;
    }
    
    /* Publication Responsive */
    .publication-card {
        flex-direction: column;
        gap: 16px;
        padding: 20px;
    }
    
    /* Contact Responsive */
    .contact-cards {
        flex-direction: column;
        align-items: center;
    }
    
    .contact-card {
        width: 100%;
        max-width: 300px;
    }
    
    /* Footer Responsive */
    .footer-content {
        flex-direction: column;
        gap: 24px;
        text-align: center;
    }
    
    .footer-brand {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .hero-cta {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 280px;
        justify-content: center;
    }
    
    .floating-card {
        display: none;
    }
    
    .tool-grid {
        grid-template-columns: 1fr;
    }
}

/* Animation Classes */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger animations */
.stagger-1 { transition-delay: 0.1s; }
.stagger-2 { transition-delay: 0.2s; }
.stagger-3 { transition-delay: 0.3s; }
.stagger-4 { transition-delay: 0.4s; }
.stagger-5 { transition-delay: 0.5s; }

/* =====================================================
   LATEST NEWS SECTION (Timeline Style)
   ===================================================== */

.news {
    background: var(--bg-primary);
}

/* Compact timeline for news */
.timeline-compact {
    max-width: 700px;
    margin: 0 auto;
}

.timeline-compact .timeline-item {
    padding-bottom: 24px;
}

.timeline-compact .timeline-content {
    padding: 16px 20px;
}

.timeline-compact .timeline-header {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.timeline-compact .timeline-date {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.timeline-compact .timeline-body {
    margin-top: 8px;
}

.news-text {
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
    font-size: 0.95rem;
}

.news-badge {
    display: inline-block;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.news-badge.new {
    background: linear-gradient(135deg, #10b981, #059669);
    color: white;
}

.news-badge.milestone {
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
    color: white;
}

.news-badge.paper {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: white;
}

/* Publication Links */
.publication-links {
    display: flex;
    gap: 24px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.pub-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 0;
    background: transparent;
    color: var(--accent-primary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.3s ease;
    position: relative;
}

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

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

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

.pub-link .link-icon {
    font-size: 1.1rem;
    transition: transform 0.3s ease;
}

.pub-link:hover .link-icon {
    transform: scale(1.2);
}

/* Advisor Link Style */
.advisor-link {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 600;
    position: relative;
    transition: all 0.3s ease;
}

.advisor-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--gradient-accent);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

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

.advisor-link:hover::after {
    transform: scaleX(1);
}

/* News Responsive */
@media (max-width: 768px) {
    .timeline-compact .timeline-content {
        padding: 12px 16px;
    }
    
    .timeline-compact .timeline-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 6px;
    }
    
    .publication-links {
        flex-direction: row;
        gap: 20px;
    }
}

/* =====================================================
   3D EFFECTS & GLOW ANIMATIONS
   ===================================================== */

/* Research Highlight - Single Card Layout */
.research-highlight {
    max-width: 800px;
    margin: 0 auto;
    perspective: 1000px;
}

/* 3D Research Card */
.research-card-3d {
    position: relative;
    background: var(--bg-card);
    border-radius: 24px;
    padding: 40px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-lg);
    transition: all 0.3s ease;
    overflow: hidden;
}

.research-card-3d:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-primary);
}

.research-card-3d .research-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    display: inline-block;
    animation: float 3s ease-in-out infinite;
}

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

.research-card-3d h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.research-card-3d p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 20px;
}

.research-card-3d .research-meta {
    display: flex;
    gap: 16px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.research-card-3d .research-date,
.research-card-3d .research-location {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 4px;
}

.research-highlights {
    list-style: none;
    margin-bottom: 24px;
    padding-left: 0;
}

.research-highlights li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 12px;
    color: var(--text-secondary);
}

.research-highlights li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--accent-primary);
    font-weight: bold;
}

.research-card-3d .research-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.research-card-3d .research-tags span {
    padding: 6px 14px;
    background: var(--gradient-soft);
    border-radius: 20px;
    font-size: 0.8rem;
    color: var(--accent-primary);
    font-weight: 500;
    border: 1px solid rgba(102, 126, 234, 0.2);
    transition: all 0.3s ease;
}

.research-card-3d .research-tags span:hover {
    background: var(--gradient-accent);
    color: white;
    transform: translateY(-2px);
}

/* 3D Effect for Publication Card */
.publication-card.featured {
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    transform-style: preserve-3d;
    position: relative;
    overflow: hidden;
}

.publication-card.featured::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at var(--mouse-x, 50%) var(--mouse-y, 50%), rgba(102, 126, 234, 0.1) 0%, transparent 50%);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
}

.publication-card.featured:hover {
    transform: translateY(-8px) scale(1.01);
    box-shadow: 
        0 20px 40px rgba(102, 126, 234, 0.2),
        0 0 40px rgba(102, 126, 234, 0.1);
}

.publication-card.featured:hover::before {
    opacity: 1;
}

/* 3D Effect for Skill Items */
.skill-category {
    transition: all 0.3s ease;
}

.skill-category:hover {
    transform: translateY(-4px);
}

.tool-item {
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.tool-item:hover {
    transform: translateY(-6px) scale(1.05);
    box-shadow: 0 12px 30px rgba(102, 126, 234, 0.2);
    background: var(--gradient-soft);
    border-color: var(--accent-primary);
}

/* Floating Cards 3D Enhancement */
.floating-card {
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.about-image:hover .floating-card.card-1 {
    transform: translate(-50%, -50%) rotate(-5deg) scale(1.1);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.3);
}

.about-image:hover .floating-card.card-2 {
    transform: translate(50%, 50%) rotate(8deg) scale(1.1);
    box-shadow: 0 15px 40px rgba(240, 147, 251, 0.3);
}

/* Image Frame 3D Effect */
.image-frame {
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.about-image:hover .image-frame {
    transform: scale(1.03);
    box-shadow: 
        0 25px 50px rgba(102, 126, 234, 0.2),
        0 0 60px rgba(102, 126, 234, 0.1);
}

/* Contact Cards Glow */
.contact-card {
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
}

.contact-card::after {
    content: '';
    position: absolute;
    top: -100%;
    left: -100%;
    width: 300%;
    height: 300%;
    background: linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.3) 50%, transparent 70%);
    transition: all 0.6s ease;
    pointer-events: none;
}

.contact-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: 
        0 20px 40px rgba(102, 126, 234, 0.2),
        0 0 30px rgba(102, 126, 234, 0.1);
}

.contact-card:hover::after {
    top: 100%;
    left: 100%;
}

/* Timeline Item Glow on Hover */
.timeline-item .timeline-content {
    transition: all 0.3s ease;
}

.timeline-item:hover .timeline-content {
    transform: translateX(8px);
    box-shadow: 
        0 10px 30px rgba(102, 126, 234, 0.15),
        -4px 0 20px rgba(102, 126, 234, 0.1);
}

.timeline-item:hover .timeline-marker {
    transform: scale(1.3);
    box-shadow: 0 0 20px rgba(102, 126, 234, 0.5);
}

/* Button Glow Effects */
.btn-primary {
    position: relative;
    overflow: hidden;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s ease;
}

.btn-primary:hover::before {
    left: 100%;
}

/* Section Title Hover Enhancement */
.section-header {
    position: relative;
    padding-left: 0;
    transition: padding-left 0.3s ease;
}

.section-header:hover {
    padding-left: 8px;
}

/* =====================================================
   ENHANCED ANIMATIONS & OPTIMIZATIONS
   ===================================================== */

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

@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.section {
    animation: fadeInUp 0.8s ease-out;
}

/* Staggered load animation */
.about { animation-delay: 0.1s; }
.news { animation-delay: 0.2s; }
.publications { animation-delay: 0.3s; }
.research { animation-delay: 0.4s; }
.skills { animation-delay: 0.5s; }
.contact { animation-delay: 0.6s; }

/* 2. Image Frame - Clean Style */
.profile-photo {
    border-radius: var(--border-radius);
}

/* 3. Enhanced Card Hover Effects */
.publication-card {
    position: relative;
    overflow: hidden;
}

.publication-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(14, 165, 233, 0.05), transparent);
    transition: left 0.5s ease;
}

.publication-card:hover::before {
    left: 100%;
}

/* Timeline enhanced hover */
.timeline-item {
    position: relative;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: transparent;
    transition: background 0.3s ease;
}

.timeline-item:hover::before {
    background: var(--gradient-accent);
}

/* 4. Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-accent);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s ease;
    z-index: 999;
    box-shadow: 0 4px 20px rgba(14, 165, 233, 0.3);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(14, 165, 233, 0.4);
}

.back-to-top svg {
    width: 24px;
    height: 24px;
}

/* 5. Skill Progress Bar Animation */
.skill-progress {
    position: relative;
    overflow: hidden;
}

.skill-progress::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* 6. Tool Item Tooltip */
.tool-item {
    position: relative;
}

.tool-item::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(-5px);
    background: var(--text-primary);
    color: white;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.75rem;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    pointer-events: none;
}

.tool-item:hover::after {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(-10px);
}

/* 7. Enhanced Interest Tags */
.interest-tags li {
    position: relative;
    overflow: hidden;
}

.interest-tags li::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.interest-tags li:hover::before {
    left: 100%;
}

/* 8. Floating Animation for Cards */
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.floating-card {
    animation: float 4s ease-in-out infinite;
}

.floating-card.card-1 {
    animation-delay: 0s;
}

.floating-card.card-2 {
    animation-delay: 1s;
}

/* 9. News Badge - Clean Style */

/* 10. Smooth Scroll Indicator */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: var(--gradient-accent);
    z-index: 1001;
    transition: width 0.1s ease;
}

/* 11. Contact Card Icon Animation */
.contact-card .contact-icon {
    transition: transform 0.3s ease;
}

.contact-card:hover .contact-icon {
    transform: scale(1.2) rotate(5deg);
}

/* 12. Footer Link Underline Animation */
.footer-links a {
    position: relative;
}

.footer-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--text-secondary);
    transition: width 0.3s ease;
}

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