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

:root {
    /* Color Palette - Clean, Academic */
    --color-primary: #1a1a1a;
    --color-secondary: #4a4a4a;
    --color-accent: #0066cc;
    --color-accent-hover: #0052a3;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-bg: #ffffff;
    --color-bg-light: #f8f9fa;
    --color-border: #e0e0e0;
    
    /* Typography */
    --font-primary: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'IBM Plex Mono', 'Courier New', monospace;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Layout */
    --max-width: 1000px;
    --border-radius: 4px;
    
    /* Transitions */
    --transition: all 0.3s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 500;
    line-height: 1.3;
    color: var(--color-primary);
}

h1 {
    font-size: 2.5rem;
    font-weight: 600;
}

h2 {
    font-size: 1.8rem;
}

h3 {
    font-size: 1.3rem;
}

p {
    margin-bottom: var(--spacing-sm);
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--color-accent-hover);
}

strong {
    font-weight: 600;
    color: var(--color-primary);
}

/* ===========================
   Navigation
   =========================== */
.navbar {
    position: sticky;
    top: 0;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    padding: var(--spacing-sm) 0;
}

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

.logo {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-primary);
    font-family: var(--font-mono);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: var(--spacing-md);
}

.nav-links a {
    color: var(--color-secondary);
    font-size: 0.95rem;
    font-weight: 400;
    transition: var(--transition);
}

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

/* ===========================
   Hero Section
   =========================== */
.hero {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.hero-content {
    max-width: 800px;
}

.name {
    margin-bottom: var(--spacing-xs);
    letter-spacing: -0.02em;
}

.title {
    font-size: 1.2rem;
    color: var(--color-secondary);
    margin-bottom: var(--spacing-xs);
    font-weight: 400;
}

.affiliation {
    font-size: 1rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

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

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    color: var(--color-secondary);
    transition: var(--transition);
}

.social-link:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    transform: translateY(-2px);
}

/* ===========================
   Sections
   =========================== */
.section {
    padding: var(--spacing-lg) 0;
}

.section-title {
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--color-primary);
    display: inline-block;
}

.bg-light {
    background-color: var(--color-bg-light);
}

/* ===========================
   About Section
   =========================== */
.about-content p {
    margin-bottom: var(--spacing-md);
    font-size: 1.05rem;
    line-height: 1.8;
}

.interests {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--color-bg-light);
    border-left: 3px solid var(--color-accent);
}

.interests h3 {
    margin-bottom: var(--spacing-sm);
    font-size: 1.1rem;
}

.interests ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xs);
}

.interests li {
    padding: var(--spacing-xs) 0;
    color: var(--color-secondary);
}

.interests li:before {
    content: "▸ ";
    color: var(--color-accent);
    font-weight: bold;
    margin-right: var(--spacing-xs);
}

/* ===========================
   Research Grid
   =========================== */
.research-grid {
    display: grid;
    gap: var(--spacing-md);
}

.research-item {
    padding: var(--spacing-md);
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.research-item:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    border-color: var(--color-accent);
}

.research-item h3 {
    margin-bottom: var(--spacing-xs);
    font-size: 1.2rem;
}

.research-meta {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-mono);
}

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

.tag {
    display: inline-block;
    padding: 0.3rem 0.7rem;
    background-color: var(--color-bg-light);
    color: var(--color-secondary);
    font-size: 0.85rem;
    border-radius: 3px;
    border: 1px solid var(--color-border);
    font-family: var(--font-mono);
}

/* ===========================
   Publications
   =========================== */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.publication {
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

.publication:last-child {
    border-bottom: none;
}

.publication h3 {
    margin-bottom: var(--spacing-xs);
    font-size: 1.15rem;
    font-weight: 500;
}

.authors {
    font-size: 0.95rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xs);
    line-height: 1.6;
}

.venue {
    font-size: 0.95rem;
    color: var(--color-secondary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    font-style: italic;
}

.publication-links {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.btn-link {
    display: inline-block;
    padding: 0.4rem 1rem;
    background-color: transparent;
    border: 1px solid var(--color-accent);
    color: var(--color-accent);
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    transition: var(--transition);
}

.btn-link:hover {
    background-color: var(--color-accent);
    color: white;
}

/* ===========================
   Timeline (Experience)
   =========================== */
.timeline {
    position: relative;
    padding-left: var(--spacing-md);
}

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

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

.timeline-marker {
    position: absolute;
    left: -27px;
    top: 5px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: var(--color-accent);
    border: 3px solid var(--color-bg);
    box-shadow: 0 0 0 2px var(--color-accent);
}

.timeline-content h3 {
    margin-bottom: var(--spacing-xs);
    font-size: 1.2rem;
}

.company {
    font-size: 1rem;
    color: var(--color-secondary);
    margin-bottom: 0.3rem;
}

.duration {
    font-size: 0.9rem;
    color: var(--color-text-light);
    font-family: var(--font-mono);
    margin-bottom: 0.3rem;
}

.location {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.timeline-content ul {
    margin-top: var(--spacing-sm);
    padding-left: var(--spacing-md);
}

.timeline-content li {
    margin-bottom: var(--spacing-xs);
    color: var(--color-secondary);
}

/* ===========================
   Education Grid
   =========================== */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.education-item {
    padding: var(--spacing-md);
    background-color: var(--color-bg-light);
    border-left: 3px solid var(--color-accent);
}

.education-item h3 {
    margin-bottom: var(--spacing-xs);
    font-size: 1.1rem;
}

.degree {
    font-weight: 500;
    color: var(--color-secondary);
    margin-bottom: 0.3rem;
}

.gpa {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: 0.3rem;
}

.cert-list {
    list-style: none;
    margin-top: var(--spacing-sm);
}

.cert-list li {
    padding: var(--spacing-xs) 0;
    border-bottom: 1px solid var(--color-border);
}

.cert-list li:last-child {
    border-bottom: none;
}

/* ===========================
   Contact Section
   =========================== */
.contact-content {
    max-width: 700px;
}

.contact-content p {
    margin-bottom: var(--spacing-md);
    font-size: 1.05rem;
}

.contact-info {
    padding: var(--spacing-md);
    background-color: var(--color-bg-light);
    border-radius: var(--border-radius);
}

.contact-info p {
    margin-bottom: var(--spacing-sm);
}

.contact-info a {
    font-weight: 500;
}

/* ===========================
   Footer
   =========================== */
.footer {
    background-color: var(--color-primary);
    color: white;
    padding: var(--spacing-md) 0;
    text-align: center;
    margin-top: var(--spacing-xl);
}

.footer p {
    margin-bottom: var(--spacing-xs);
    font-size: 0.9rem;
    opacity: 0.8;
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 768px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    h2 {
        font-size: 1.5rem;
    }
    
    .nav-links {
        gap: var(--spacing-sm);
    }
    
    .nav-links a {
        font-size: 0.9rem;
    }
    
    .hero {
        padding: var(--spacing-lg) 0 var(--spacing-md);
    }
    
    .research-grid {
        grid-template-columns: 1fr;
    }
    
    .education-grid {
        grid-template-columns: 1fr;
    }
    
    .interests ul {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .navbar .container {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .nav-links {
        gap: var(--spacing-xs);
        flex-wrap: wrap;
        justify-content: center;
    }
    
    h1 {
        font-size: 1.75rem;
    }
    
    .social-links {
        justify-content: flex-start;
    }
    
    .publication-links {
        flex-direction: column;
    }
    
    .btn-link {
        text-align: center;
    }
}

/* ===========================
   Utility Classes
   =========================== */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }

/* ===========================
   Print Styles
   =========================== */
@media print {
    .navbar,
    .social-links,
    .footer {
        display: none;
    }
    
    .section {
        page-break-inside: avoid;
    }
}