:root {
    /* Refined Elegant Color Palette */
    --bg-primary: #fefefe;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f8f9fa;
    --text-primary: #1a1a1a;
    --text-secondary: #4a5568;
    --text-tertiary: #718096;
    
    /* Subtle Accent Colors */
    --accent-primary: #2d3748;
    --accent-secondary: #4a5568;
    --accent-tertiary: #718096;
    --accent-warm: #d69e2e;
    
    /* Refined Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.9);
    --glass-border: rgba(0, 0, 0, 0.05);
    --glass-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    
    /* Elegant Spacing System */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 2.5rem;
    --space-2xl: 3.5rem;
    --space-3xl: 5rem;
    
    /* Refined Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 0.75rem;
    
    /* Subtle Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-xl: 0 8px 24px rgba(0, 0, 0, 0.1);
    
    /* Legacy support */
    --accent-color: var(--accent-primary);
    --link-hover: #2d3748;
}

/* Modern Typography System */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    line-height: 1.7;
    font-size: 16px;
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    line-height: 1.3;
    letter-spacing: -0.01em;
    color: var(--text-primary);
}

h1 { font-size: clamp(2rem, 4vw, 3rem); font-weight: 600; }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); }
h3 { font-size: clamp(1.25rem, 2.5vw, 1.5rem); }
h4 { font-size: 1.125rem; }
h5 { font-size: 1rem; }
h6 { font-size: 0.9rem; }

/* Modern Navigation */
.navbar {
    background-color: transparent;
    padding: var(--space-lg) 0;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(0px);
}

.navbar.scrolled {
    background-color: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    padding: var(--space-md) 0;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.25rem;
    letter-spacing: -0.025em;
    color: var(--text-primary) !important;
    text-decoration: none;
    transition: all 0.3s ease;
}

.navbar-brand:hover {
    color: var(--accent-primary) !important;
    transform: translateY(-1px);
}

.nav-link {
    color: var(--text-secondary) !important;
    font-size: 0.9rem;
    font-weight: 500;
    margin-left: var(--space-lg);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    text-decoration: none !important;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--accent-primary);
    transition: width 0.3s ease;
}

.nav-link:hover {
    color: var(--text-primary) !important;
}

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

/* Modern Section Spacing */
section {
    padding: var(--space-3xl) 0;
    position: relative;
}

/* Elegant Hero Section */
.hero-section {
    min-height: 90vh;
    display: flex;
    align-items: center;
    background: var(--bg-primary);
    position: relative;
    margin-top: 2rem;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 40%;
    height: 100%;
    background: linear-gradient(135deg, rgba(45, 55, 72, 0.02) 0%, transparent 50%);
    pointer-events: none;
}

.hero-title {
    font-size: clamp(2rem, 4vw, 3rem);
    line-height: 1.2;
    margin-bottom: var(--space-lg);
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--text-primary);
}

.hero-text {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
    line-height: 1.7;
    max-width: 600px;
}

.hero-image {
    width: 100%;
    height: 750px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
    transition: all 0.3s ease;
    background: var(--bg-tertiary);
}

.hero-image:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.profile-photo {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: var(--radius-lg);
    transition: all 0.3s ease;
}

.hero-image:hover .profile-photo {
    transform: scale(1.02);
}

.btn-custom {
    background-color: var(--accent-primary);
    color: white;
    padding: 0.8rem 2.5rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 0.85rem;
    border: none;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(52, 152, 219, 0.3);
}

.btn-custom:hover {
    background-color: var(--link-hover);
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(52, 152, 219, 0.4);
}

/* Modern Button System */
.btn-custom {
    background-color: var(--accent-primary);
    color: white;
    padding: var(--space-sm) var(--space-lg);
    font-weight: 500;
    font-size: 0.9rem;
    border: none;
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
    text-decoration: none;
    display: inline-block;
    letter-spacing: 0.01em;
}

.btn-custom:hover {
    background-color: var(--text-primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
    color: white;
}

/* Hero Actions */
.hero-actions {
    display: flex;
    gap: var(--space-md);
    margin-top: var(--space-lg);
    flex-wrap: wrap;
}

.btn-outline-custom {
    background: transparent;
    color: var(--accent-primary);
    padding: var(--space-sm) var(--space-lg);
    font-weight: 500;
    font-size: 0.9rem;
    border: 1px solid var(--accent-primary);
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    letter-spacing: 0.01em;
}

.btn-outline-custom:hover {
    background: var(--accent-primary);
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

/* Section Titles */
.section-title {
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: var(--space-2xl);
    text-align: center;
    font-weight: 700;
    letter-spacing: -0.02em;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -var(--space-xs);
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 2px;
    background: var(--accent-primary);
    border-radius: 1px;
}

/* Modern Card System */
.resume-card {
    background: var(--bg-secondary);
    padding: var(--space-xl);
    margin-bottom: var(--space-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.resume-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: var(--accent-primary);
    transform: scaleY(0);
    transform-origin: bottom;
    transition: transform 0.3s ease;
}

.resume-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: rgba(45, 55, 72, 0.1);
}

.resume-card:hover::before {
    transform: scaleY(1);
    transform-origin: top;
}

.resume-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
    font-weight: 600;
    color: var(--text-primary);
}

.resume-card .institution {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    margin-bottom: var(--space-xs);
}

.resume-card .date {
    color: var(--text-tertiary);
    font-size: 0.85rem;
    font-style: italic;
    margin-bottom: var(--space-md);
}

.resume-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* Modern Publication Cards */
.publication-item {
    background: var(--bg-secondary);
    padding: var(--space-xl);
    margin-bottom: var(--space-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.publication-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: var(--accent-secondary);
    transform: scaleY(0);
    transform-origin: bottom;
    transition: transform 0.3s ease;
}

.publication-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: rgba(74, 85, 104, 0.1);
}

.publication-item:hover::before {
    transform: scaleY(1);
    transform-origin: top;
}

.publication-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
    line-height: 1.4;
}

.publication-authors {
    color: var(--text-secondary);
    margin-bottom: var(--space-xs);
    font-size: 0.95rem;
    font-weight: 500;
}

.publication-venue {
    color: var(--text-tertiary);
    font-size: 0.9rem;
    margin-bottom: var(--space-md);
}

.publication-video {
    width: 100%;
    height: 200px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: var(--space-md);
    color: var(--text-tertiary);
    border: 1px dashed var(--accent-tertiary);
    transition: all 0.3s ease;
}

.publication-video:hover {
    border-color: var(--accent-secondary);
    background: #e2e8f0;
    transform: none;
}

/* Modern Link System */
a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

a:hover {
    color: var(--link-hover);
    text-decoration: underline;
    text-decoration-color: var(--accent-primary);
    text-underline-offset: 2px;
}

/* Modern Footer */
footer {
    background: var(--bg-secondary);
    padding: var(--space-xl) 0;
    text-align: center;
    color: var(--text-tertiary);
    font-size: 0.9rem;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    margin-top: var(--space-3xl);
}


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

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 6px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--accent-tertiary);
    border-radius: 3px;
}

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

/* Loading Animation */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.4s ease-out;
}

/* Focus States for Accessibility */
.btn-custom:focus,
.btn-outline-custom:focus,
.nav-link:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* Keyboard Navigation */
.keyboard-navigation *:focus {
    outline: 2px solid var(--accent-primary) !important;
    outline-offset: 2px !important;
}

/* Print Styles */
@media print {
    .navbar {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .hero-section {
        min-height: auto;
        padding: 2rem 0;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-section {
        min-height: 80vh;
        text-align: center;
    }
    
    .hero-image {
        transform: none;
        margin-top: var(--space-lg);
    }
    
    .hero-image:hover {
        transform: scale(1.02);
    }
    
    .nav-link {
        margin-left: var(--space-md);
    }
    
    section {
        padding: var(--space-2xl) 0;
    }
    
    .resume-card,
    .publication-item {
        padding: var(--space-lg);
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .btn-custom {
        padding: var(--space-sm) var(--space-lg);
        font-size: 0.85rem;
    }
}