/* Modern CSS Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Variables */
:root {
    /* Primary Colors - Professional Blue (Enterprise/BioNTech aligned) */
    --primary-color: #2563eb;      /* Blue 600 - Trust, stability */
    --secondary-color: #1d4ed8;    /* Blue 700 - Professional depth */
    --primary-gradient: linear-gradient(135deg, #2563eb 0%, #0891b2 100%);
    --primary-gradient-hover: linear-gradient(135deg, #1d4ed8 0%, #0e7490 100%);

    /* Text Colors */
    --text-color: #1e293b;         /* Slate 800 - Primary text */
    --light-text: #475569;         /* Slate 600 - Secondary text (improved contrast) */
    --heading-color: #0f172a;      /* Slate 900 - Headings */

    /* Background Colors - Enhanced */
    --bg-color: #f8fafc;           /* Slate 50 - Main background */
    --section-bg: #f1f5f9;         /* Slate 100 - Section background */
    --card-bg: #ffffff;            /* White - Card background */
    --glass-bg: rgba(255, 255, 255, 0.8);
    --glass-border: rgba(255, 255, 255, 0.4);

    /* Accent Colors */
    --accent-1: #0891b2;          /* Cyan 600 - Tech accent (BioNTech aligned) */
    --accent-2: #0891b2;          /* Cyan 600 - Secondary accent */
    --accent-3: #059669;          /* Emerald 600 - Success accent */

    /* Other Variables - Enhanced */
    --max-width: 1200px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease;
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --shadow-colored: 0 10px 40px -10px rgba(37, 99, 235, 0.3);
    --border-radius: 0.75rem;
    --border-radius-lg: 1.25rem;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.07), 0 1px 3px rgba(0, 0, 0, 0.05);
}

/* Base Styles */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    overflow-x: hidden;
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Focus states for accessibility */
*:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
}

/* Typography - Enhanced */
h1, h2, h3, h4 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    color: var(--heading-color);
    margin-bottom: 1.5rem;
    font-weight: 800;
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    color: var(--heading-color);
    margin-bottom: 2.5rem;
    text-align: center;
    position: relative;
}

/* Section title underline decoration */
section h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--primary-gradient);
    margin: 1rem auto 0;
    border-radius: 2px;
}

h3 {
    font-size: 1.5rem;
    color: var(--heading-color);
    font-weight: 600;
}

h4 {
    font-size: 1.25rem;
    color: var(--light-text);
    font-weight: 500;
}

p {
    line-height: 1.7;
}

/* Navigation - Enhanced with glassmorphism */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 1000;
    border-bottom: 1px solid rgba(255, 255, 255, 0.3);
    transition: var(--transition);
}

header.scrolled {
    box-shadow: var(--shadow-lg);
    background-color: rgba(255, 255, 255, 0.95);
}

nav {
    padding: 1rem 0;
}

.nav-content {
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    position: relative;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    padding: 0.5rem;
    border: 2px solid var(--primary-color);
    border-radius: 0.5rem;
    line-height: 1;
    transition: all 0.2s ease;
}

.logo:hover {
    background-color: var(--primary-color);
    color: white;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    flex-wrap: wrap;
    justify-content: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    font-size: 0.9rem;
    padding: 0.5rem 0.75rem;
    border-radius: var(--border-radius);
}

/* Animated underline effect for nav links */
.nav-links a::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary-gradient);
    transition: var(--transition);
    transform: translateX(-50%);
    border-radius: 1px;
}

.nav-links a:hover::before {
    width: calc(100% - 1.5rem);
}

.nav-links a[target="_blank"]::after {
    content: '↗';
    position: relative;
    top: -0.5em;
    font-size: 0.7em;
    margin-left: 0.2em;
    opacity: 0.7;
}

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

@media (max-width: 1024px) {
    .nav-links {
        gap: 1rem;
    }
    
    .nav-links a {
        font-size: 0.85rem;
    }
}

@media (max-width: 768px) {
    .nav-content {
        flex-direction: column;
        padding: 1rem;
    }

    .nav-links {
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
        gap: 0.75rem;
        margin-top: 1rem;
        width: 100%;
    }

    .nav-links li {
        width: auto;
    }

    .nav-links a {
        display: block;
        padding: 0.5rem 0.75rem;
        font-size: 0.85rem;
        background-color: var(--section-bg);
        border-radius: 1rem;
        text-align: center;
    }

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

/* Hero Section - Complete Redesign */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(37, 99, 235, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(8, 145, 178, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 100%, rgba(6, 182, 212, 0.05) 0%, transparent 50%),
        linear-gradient(180deg, var(--section-bg) 0%, var(--bg-color) 100%);
    padding: 8rem 2rem 6rem;
    position: relative;
    overflow: hidden;
}

/* Decorative background elements */
#hero::before {
    content: '';
    position: absolute;
    top: 20%;
    right: 10%;
    width: 300px;
    height: 300px;
    background: var(--primary-gradient);
    opacity: 0.03;
    border-radius: 50%;
    filter: blur(60px);
    animation: float 8s ease-in-out infinite;
}

#hero::after {
    content: '';
    position: absolute;
    bottom: 20%;
    left: 10%;
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, var(--accent-2), var(--accent-1));
    opacity: 0.03;
    border-radius: 50%;
    filter: blur(60px);
    animation: float 8s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% { transform: translateY(0) scale(1); }
    50% { transform: translateY(-20px) scale(1.05); }
}

.hero-content {
    max-width: var(--max-width);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4rem;
    position: relative;
    z-index: 1;
}

.hero-text {
    text-align: center;
    max-width: 800px;
}

/* Hero Company Badge */
.hero-company {
    font-size: 1rem;
    color: var(--light-text);
    margin-bottom: 0.75rem;
    font-weight: 500;
}

.hero-company strong {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.hero-text h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    line-height: 1.1;
    margin-bottom: 0.75rem;
    text-align: center;
    color: var(--heading-color);
    font-weight: 800;
    letter-spacing: -0.03em;
}

/* Hero Subtitle and Tagline */
.hero-subtitle {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.hero-tagline {
    font-size: 1.1rem;
    color: var(--light-text);
    margin-bottom: 2rem;
    max-width: 550px;
    margin-left: auto;
    margin-right: auto;
}

.name-note {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.25rem;
    margin-bottom: 2rem;
}

.name-note span {
    font-size: 0.95rem;
    color: var(--light-text);
    letter-spacing: 0.05em;
    font-weight: 400;
    text-transform: uppercase;
}

.name-note .divider {
    height: 1px;
    width: 2rem;
    background: linear-gradient(90deg, transparent, var(--light-text), transparent);
    opacity: 0.5;
}

.hero-text h2 {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: clamp(1.5rem, 4vw, 2.25rem);
    margin-bottom: 1.5rem;
    text-align: center;
    font-weight: 700;
}

/* Remove the underline for hero h2 */
.hero-text h2::after {
    display: none;
}

.hero-text p {
    font-size: 1.15rem;
    color: var(--light-text);
    margin-bottom: 2.5rem;
    text-align: center;
    max-width: 40rem;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.8;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
    width: 100%;
    max-width: 1000px;
}

.stat-item {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 2rem 1.5rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--card-shadow);
    border: 1px solid var(--glass-border);
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.stat-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
    opacity: 0;
    transition: var(--transition);
}

.stat-item:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-colored);
}

.stat-item:hover::before {
    opacity: 1;
}

.stat-number {
    display: block;
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.stat-label {
    color: var(--light-text);
    font-size: 0.9rem;
    font-weight: 500;
    line-height: 1.4;
    display: block;
}

.stat-detail {
    display: block;
    font-size: 0.8rem;
    color: var(--accent-2);
    margin-top: 0.25rem;
    font-weight: 500;
}

@media (max-width: 1200px) {
    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
        padding: 0 1rem;
    }
}

@media (max-width: 768px) {
    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }
}

@media (max-width: 480px) {
    .hero-stats {
        grid-template-columns: 1fr;
    }
    
    .stat-item {
        padding: 1.5rem;
    }
    
    .stat-number {
        font-size: 2rem;
    }
}

/* Hero Buttons Container */
.hero-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons - Enhanced */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
}

.btn-primary::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: var(--transition-slow);
}

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

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(37, 99, 235, 0.4);
}

.btn-secondary {
    background-color: white;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    box-shadow: var(--card-shadow);
}

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-3px);
    box-shadow: var(--shadow-colored);
}

.btn i {
    font-size: 1.1rem;
}

/* Sections - Enhanced spacing */
section {
    padding: 7rem 0;
    position: relative;
}

section:nth-child(even) {
    background-color: var(--section-bg);
}

/* Subtle section transitions */
section:not(#hero)::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(0,0,0,0.05), transparent);
}

/* About Section - Card Grid Layout */
.about-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    max-width: 1000px;
    margin: 0 auto;
}

.about-card {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border: 1px solid transparent;
}

.about-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(37, 99, 235, 0.1);
}

.about-card i {
    font-size: 2rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1rem;
    display: inline-block;
}

.about-card h3 {
    font-size: 1.1rem;
    color: var(--heading-color);
    margin-bottom: 0.75rem;
}

.about-card p {
    color: var(--light-text);
    font-size: 0.95rem;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .about-grid {
        grid-template-columns: 1fr;
        padding: 0 1rem;
    }
}

.about-highlights {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.highlight-item {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1rem;
    text-align: center;
    transition: transform 0.3s;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

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

.highlight-item i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.highlight-item span {
    display: block;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.highlight-item small {
    color: var(--light-text);
    font-size: 0.9rem;
}

/* Academic Section - Enhanced */
.academic-grid {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 850px;
    margin: 0 auto;
}

.academic-card {
    background: white;
    padding: 2.5rem;
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    width: 100%;
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.academic-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
    transform: scaleX(0);
    transition: var(--transition);
}

.academic-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: rgba(37, 99, 235, 0.1);
}

.academic-card:hover::before {
    transform: scaleX(1);
}

.academic-card i {
    font-size: 2.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1.5rem;
    display: inline-block;
}

.academic-card .publication-link i {
    font-size: 0.9rem;
    -webkit-text-fill-color: white;
    margin: 0;
}

.academic-card h3 {
    color: var(--heading-color);
    font-size: 1.4rem;
    margin-bottom: 1rem;
}

.academic-card p {
    color: var(--light-text);
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 1rem;
}

.publication-details {
    font-size: 0.9rem;
    color: var(--accent-2);
    font-style: normal;
    font-weight: 500;
    margin-bottom: 1.5rem;
    padding: 0.5rem 1rem;
    background: rgba(6, 182, 212, 0.08);
    border-radius: 2rem;
    display: inline-block;
}

.publication-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--primary-gradient);
    color: white;
    text-decoration: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 0.9rem;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.25);
}

.publication-link:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(37, 99, 235, 0.35);
}

@media (max-width: 768px) {
    .academic-grid {
        padding: 0 1rem;
    }
    
    .academic-card {
        padding: 2rem;
    }
}

/* Expertise Section - Enhanced */
.expertise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.expertise-card {
    padding: 2rem;
    background-color: var(--card-bg);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    text-align: center;
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

/* Subtle gradient border on hover */
.expertise-card::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--border-radius-lg);
    padding: 2px;
    background: var(--primary-gradient);
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    opacity: 0;
    transition: var(--transition);
}

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

.expertise-card:hover::after {
    opacity: 1;
}

.expertise-card i {
    font-size: 2.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1.25rem;
    display: inline-block;
    transition: var(--transition);
}

.expertise-card:hover i {
    transform: scale(1.1);
}

.expertise-card h3 {
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
}

.expertise-card p {
    color: var(--light-text);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Projects Section - Enhanced */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.5rem;
    padding: 0;
}

.projects-grid h2 {
    grid-column: 1 / -1;
    margin-bottom: 1rem;
}

.project-card {
    background: white;
    border: 1px solid rgba(0, 0, 0, 0.06);
    border-radius: var(--border-radius-lg);
    padding: 1.75rem;
    transition: var(--transition);
    width: 100%;
    position: relative;
    overflow: hidden;
}

.project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

.project-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.project-card:hover {
    border-color: rgba(37, 99, 235, 0.2);
    box-shadow: var(--shadow-lg);
    transform: translateY(-5px);
}

.project-card:hover::before {
    transform: scaleX(1);
}

.project-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.project-header i {
    font-size: 1.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.project-header h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--heading-color);
    margin: 0;
    transition: var(--transition);
}

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

.project-card p {
    color: var(--light-text);
    font-size: 0.9rem;
    line-height: 1.6;
    margin: 0.75rem 0;
}

.project-stats {
    display: flex;
    gap: 1.25rem;
    margin: 1.25rem 0 0.5rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.project-stats span {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.85rem;
    color: var(--light-text);
    font-weight: 500;
}

.project-stats i {
    font-size: 0.9rem;
    color: var(--accent-1);
}

.featured-project {
    margin: 0 auto;
    grid-column: 1 / -1;
    justify-self: center;
    max-width: 400px;
}

/* Loading and Error States */
.loading-state,
.error-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 3rem 2rem;
    color: var(--light-text);
}

.loading-state i,
.error-state i {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
}

.loading-state i {
    color: var(--primary-color);
}

.error-state i {
    color: #ef4444;
}

.loading-state p,
.error-state p {
    font-size: 1rem;
    margin-bottom: 1rem;
}

.retry-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
}

.retry-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
}

.retry-btn:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Screen reader only utility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Footer - Enhanced */
footer {
    background: linear-gradient(135deg, var(--heading-color) 0%, #334155 100%);
    color: white;
    padding: 3rem 0;
    text-align: center;
    position: relative;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
}

footer p {
    opacity: 0.9;
    font-size: 0.95rem;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.25rem;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    font-size: 1.5rem;
    transition: var(--transition);
}

.footer-links a:hover {
    color: white;
    transform: translateY(-3px);
}

/* Accessibility Skip Link */
.skip-link {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-weight: 600;
    z-index: 9999;
    transition: top 0.3s ease;
    text-decoration: none;
}

.skip-link:focus {
    top: 1rem;
}

/* Skills Section */
.skills-section {
    margin: 2rem 0;
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.skills-section h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.skill-category h4 {
    color: var(--text-color);
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.skill-tag {
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(8, 145, 178, 0.1));
    color: var(--primary-color);
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.85rem;
    font-weight: 500;
    transition: var(--transition);
    border: 1px solid rgba(37, 99, 235, 0.2);
}

.skill-tag:hover {
    background: var(--primary-gradient);
    color: white;
    border-color: transparent;
    transform: translateY(-2px);
}

/* Enhanced Skills Section */
.skill-category {
    background: var(--card-bg);
    padding: 1.75rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border: 1px solid transparent;
}

.skill-category:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(37, 99, 235, 0.1);
}

.skill-category h3 {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--heading-color);
}

.skill-category h3 i {
    font-size: 1.25rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Education Section */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    max-width: 800px;
    margin: 0 auto;
}

.education-card {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.education-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
    transform: scaleX(0);
    transition: var(--transition);
}

.education-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: rgba(37, 99, 235, 0.1);
}

.education-card:hover::before {
    transform: scaleX(1);
}

.education-card i {
    font-size: 2.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1.25rem;
    display: inline-block;
}

.education-card h3 {
    color: var(--heading-color);
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.degree-focus {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.institution {
    color: var(--light-text);
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

.badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent-3), #059669);
    color: white;
    padding: 0.35rem 0.85rem;
    border-radius: 2rem;
    font-size: 0.8rem;
    font-weight: 600;
}

/* Publications Section */
.publications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 1.5rem;
    max-width: 900px;
    margin: 0 auto;
}

.publication-card {
    background: white;
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    display: flex;
    gap: 1.5rem;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.publication-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--primary-gradient);
    transform: scaleY(0);
    transition: var(--transition);
}

.publication-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(37, 99, 235, 0.1);
}

.publication-card:hover::before {
    transform: scaleY(1);
}

.publication-icon {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(8, 145, 178, 0.1));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.publication-icon i {
    font-size: 1.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.publication-content {
    flex: 1;
}

.publication-role-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-1));
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 2rem;
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.publication-content h3 {
    font-size: 1.1rem;
    color: var(--heading-color);
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.publication-journal {
    color: var(--accent-2);
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
}

.publication-org {
    color: var(--light-text);
    font-size: 0.85rem;
    margin-bottom: 1rem;
}

.publication-content .publication-link {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

@media (max-width: 768px) {
    .education-grid {
        grid-template-columns: 1fr;
        padding: 0 1rem;
    }

    .publications-grid {
        grid-template-columns: 1fr;
        padding: 0 1rem;
    }

    .publication-card {
        flex-direction: column;
        align-items: center;
        text-align: center;
        padding: 1.5rem;
    }

    .publication-card::before {
        top: 0;
        left: 0;
        right: 0;
        width: 100%;
        height: 4px;
        transform: scaleX(0);
    }

    .publication-card:hover::before {
        transform: scaleX(1);
    }
}

/* Achievements Section */
.achievements {
    margin: 2rem 0;
}

.achievements h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

.achievement-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.achievement-item {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1rem;
    transition: transform 0.3s;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

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

.achievement-item i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.achievement-item h4 {
    color: var(--text-color);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.achievement-item p {
    color: var(--light-text);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* Infrastructure Section - Enhanced */
#infrastructure {
    background-color: var(--section-bg);
    padding: 7rem 0;
}

.cluster-card {
    background: white;
    border-radius: var(--border-radius-lg);
    padding: 3rem;
    max-width: 1000px;
    margin: 0 auto;
    box-shadow: var(--card-shadow);
    border: 1px solid rgba(0, 0, 0, 0.04);
}

.cluster-info {
    margin-bottom: 3rem;
    text-align: center;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.cluster-info h3 {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.cluster-info p {
    color: var(--light-text);
    font-size: 1rem;
    line-height: 1.7;
}

.cluster-nodes {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
}

.node {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.75rem 1.25rem;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: 600;
    color: white;
    min-width: 120px;
    justify-content: center;
    transition: var(--transition);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.node:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.node i {
    font-size: 1rem;
}

.master {
    background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.worker {
    background: var(--primary-gradient);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.25);
}

.worker-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 0.75rem;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

@media (max-width: 1200px) {
    .worker-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 1rem;
        max-width: 600px;
    }
}

@media (max-width: 768px) {
    .cluster-card {
        padding: 2rem;
        margin: 0 1rem;
    }

    .worker-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
        max-width: 400px;
    }

    .cluster-info {
        margin-bottom: 2rem;
    }
}

@media (max-width: 480px) {
    .worker-grid {
        grid-template-columns: 1fr;
        max-width: 200px;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-stats {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .about-highlights {
        grid-template-columns: 1fr;
    }

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

    /* Mobile navigation - using pills instead of hiding */

    .skills-grid,
    .achievement-grid {
        grid-template-columns: 1fr;
    }

    .skills-section,
    .highlight-item,
    .achievement-item {
        padding: 1rem;
    }
}

/* Animations - Enhanced */
@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);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* Staggered animations for cards */
.expertise-card,
.academic-card,
.project-card,
.stat-item {
    animation: fadeInUp 0.6s ease-out backwards;
}

.expertise-card:nth-child(1) { animation-delay: 0.1s; }
.expertise-card:nth-child(2) { animation-delay: 0.2s; }
.expertise-card:nth-child(3) { animation-delay: 0.3s; }
.expertise-card:nth-child(4) { animation-delay: 0.4s; }
.expertise-card:nth-child(5) { animation-delay: 0.5s; }
.expertise-card:nth-child(6) { animation-delay: 0.6s; }

.stat-item:nth-child(1) { animation-delay: 0.2s; }
.stat-item:nth-child(2) { animation-delay: 0.35s; }
.stat-item:nth-child(3) { animation-delay: 0.5s; }

/* Section entrance animation */
section {
    animation: fadeInUp 0.7s ease-out;
}

/* Reduce motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Open Source Section - Enhanced */
.contribution-card {
    background: white;
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--card-shadow);
    max-width: 400px;
    margin: 0 auto;
    text-align: center;
    border: 1px solid rgba(0, 0, 0, 0.04);
    transition: var(--transition);
}

.contribution-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.contribution-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.25rem;
}

.contribution-content i {
    font-size: 2.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.contribution-content h3 {
    font-size: 1.35rem;
    color: var(--heading-color);
    margin: 0;
    font-weight: 600;
}

.contribution-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--primary-gradient);
    color: white;
    text-decoration: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 0.9rem;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.25);
}

.contribution-link:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(37, 99, 235, 0.35);
}

.contribution-link i {
    font-size: 1rem;
    -webkit-text-fill-color: white;
    margin: 0;
}

@media (max-width: 768px) {
    .contribution-card {
        padding: 1.25rem;
        margin: 0 1rem;
    }
}

.project-links {
    margin-top: 1rem;
}

.doc-link {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.75rem;
    background-color: #2563eb;
    color: white;
    text-decoration: none;
    border-radius: 0.5rem;
    font-weight: 500;
    font-size: 0.875rem;
    transition: background-color 0.2s ease;
}

.doc-link:hover {
    background-color: #1d4ed8;
    transform: translateY(-2px);
}

.doc-link i {
    font-size: 1rem;
}

/* Scroll Indicator for Hero */
.scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    color: var(--light-text);
    font-size: 0.85rem;
    font-weight: 500;
    opacity: 0.7;
    animation: bounce 2s infinite;
    cursor: pointer;
    transition: var(--transition);
}

.scroll-indicator:hover {
    opacity: 1;
    color: var(--primary-color);
}

.scroll-indicator i {
    font-size: 1.25rem;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
    40% { transform: translateX(-50%) translateY(-10px); }
    60% { transform: translateX(-50%) translateY(-5px); }
}

/* Loading animation for images */
.loading {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* Custom scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--section-bg);
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--primary-color), var(--accent-1));
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}

/* Mobile-specific improvements */
@media (max-width: 768px) {
    /* Mobile navigation - pill style */
    .nav-links {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 0.5rem;
        padding: 0.5rem;
    }

    .nav-links a {
        font-size: 0.8rem;
        padding: 0.5rem 0.75rem;
        background: var(--section-bg);
        border-radius: 2rem;
    }

    .nav-links a::before {
        display: none;
    }

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

    /* Hero adjustments */
    #hero {
        padding: 7rem 1.5rem 4rem;
    }

    .hero-text h1 {
        font-size: 2.25rem;
    }

    .hero-text h2 {
        font-size: 1.25rem;
    }

    .hero-text p {
        font-size: 1rem;
    }

    .hero-stats {
        gap: 1rem;
    }

    .stat-item {
        padding: 1.25rem 1rem;
    }

    .stat-number {
        font-size: 1.75rem;
    }

    .stat-label {
        font-size: 0.8rem;
    }

    /* Section padding */
    section {
        padding: 4rem 0;
    }

    section h2 {
        font-size: 1.5rem;
        margin-bottom: 2rem;
    }

    /* Cards */
    .expertise-card,
    .academic-card {
        padding: 1.5rem;
    }

    .about-text {
        padding: 1.5rem;
        font-size: 1rem;
    }

    /* Scroll indicator hidden on mobile */
    .scroll-indicator {
        display: none;
    }
}

/* Tablet improvements */
@media (min-width: 769px) and (max-width: 1024px) {
    .hero-stats {
        grid-template-columns: repeat(3, 1fr);
        gap: 1rem;
    }

    .expertise-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    section {
        padding: 5rem 0;
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #1e40af;
        --light-text: #374151;
        --card-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    }

    .btn-primary,
    .publication-link,
    .contribution-link {
        border: 2px solid white;
    }
}

/* Dark mode preparation (for future implementation) */
@media (prefers-color-scheme: dark) {
    /*
    :root {
        --bg-color: #0f172a;
        --section-bg: #1e293b;
        --card-bg: #1e293b;
        --text-color: #f1f5f9;
        --light-text: #94a3b8;
        --heading-color: #f8fafc;
    }
    */
}

/* Reduced transparency support */
@media (prefers-reduced-transparency: reduce) {
    header {
        backdrop-filter: none;
        -webkit-backdrop-filter: none;
        background: rgba(255, 255, 255, 0.98);
    }

    .stat-item,
    .glass-bg {
        backdrop-filter: none;
        -webkit-backdrop-filter: none;
        background: white;
    }
}

/* Print Styles */
@media print {
    /* Reset backgrounds and colors for print */
    *,
    *::before,
    *::after {
        background: white !important;
        color: black !important;
        box-shadow: none !important;
        text-shadow: none !important;
    }

    /* Hide non-essential elements */
    header,
    footer,
    .skip-link,
    .scroll-indicator,
    .hero-links,
    .publication-link,
    .contribution-link,
    .btn,
    #infrastructure,
    #opensource {
        display: none !important;
    }

    /* Show full URLs for links */
    a[href^="http"]::after {
        content: " (" attr(href) ")";
        font-size: 0.75em;
        color: #666 !important;
        word-break: break-all;
    }

    /* Don't show URL for nav and button links */
    .nav-links a::after,
    .btn::after,
    .publication-link::after,
    .contribution-link::after {
        content: none !important;
    }

    /* Page break handling */
    section {
        page-break-inside: avoid;
        break-inside: avoid;
        padding: 1.5rem 0 !important;
    }

    h1, h2, h3 {
        page-break-after: avoid;
        break-after: avoid;
    }

    /* Reset gradient text for print */
    .stat-number,
    .hero-subtitle,
    .hero-company strong,
    .about-card i,
    .skill-category h3 i,
    .expertise-card i,
    .education-card i,
    .publication-icon i,
    .cluster-info h3,
    .project-header i {
        -webkit-text-fill-color: black !important;
        background: none !important;
        color: black !important;
    }

    /* Layout adjustments for print */
    .hero-content,
    .about-grid,
    .skills-grid,
    .expertise-grid,
    .projects-grid,
    .education-grid,
    .publications-grid {
        display: block !important;
    }

    .stat-item,
    .about-card,
    .skill-category,
    .expertise-card,
    .project-card,
    .education-card,
    .publication-card {
        page-break-inside: avoid;
        break-inside: avoid;
        margin-bottom: 1rem !important;
        border: 1px solid #ddd !important;
        padding: 1rem !important;
    }

    /* Hero section adjustments */
    #hero {
        min-height: auto !important;
        padding: 1rem 0 !important;
    }

    .hero-stats {
        display: flex !important;
        flex-wrap: wrap;
        gap: 1rem;
    }

    .stat-item {
        flex: 1 1 45%;
    }

    /* Typography for print */
    body {
        font-size: 12pt !important;
        line-height: 1.5 !important;
    }

    h1 {
        font-size: 24pt !important;
    }

    h2 {
        font-size: 18pt !important;
    }

    h3 {
        font-size: 14pt !important;
    }

    /* Section title underline */
    section h2::after {
        background: black !important;
    }

    /* Page settings */
    @page {
        margin: 2cm;
        size: A4;
    }

    @page :first {
        margin-top: 1cm;
    }

    /* Add print header */
    body::before {
        content: "John Euko - AI & MLOps Engineer | joaopeuko.com";
        display: block;
        text-align: center;
        font-size: 10pt;
        color: #666 !important;
        margin-bottom: 1rem;
        padding-bottom: 0.5rem;
        border-bottom: 1px solid #ddd;
    }
}