/* ============================================================================
   GLOBAL STYLES & VARIABLES
   ============================================================================ */

:root {
    --primary-color: #6EE7B7;
    --primary-dark: #34D399;
    --accent-gold: #F59E0B;
    --accent-blue: #3B82F6;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #F0FDF4;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --accent-color: #059669;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.8;
    color: var(--text-primary);
    background-color: var(--bg-white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ============================================================================
   NAVIGATION
   ============================================================================ */

#navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--bg-white);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: var(--transition);
}

#navbar.scrolled {
    box-shadow: var(--shadow-md);
}

#navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

.nav-brand {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 3px 0;
    transition: var(--transition);
}

/* ============================================================================
   HERO SECTION
   ============================================================================ */

#hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, #F1F8E9 0%, #E8F5E9 100%);
    color: var(--text-primary);
    position: relative;
    overflow: hidden;
}


.hero-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    align-items: center;
    position: relative;
    z-index: 1;
}


.hero-text h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 1rem;
    opacity: 0.95;
}

.affiliation {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    border: none;
    cursor: pointer;
}

.btn-primary {
    background-color: var(--bg-white);
    color: var(--text-primary);
    border: 2px solid var(--primary-color);
}

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

.btn-secondary {
    background-color: var(--bg-white);
    color: var(--text-primary);
    border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: var(--bg-white);
}

.hero-image {
    display: flex;
    justify-content: center;
}

.hero-image img {
    width: 100%;
    max-width: 305px;
    height: auto;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    object-fit: cover;
}

/* ============================================================================
   SECTIONS
   ============================================================================ */

section {
    padding: 5rem 0;
}

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

/* Section fade-in on scroll (already handled by script.js) */
.section-visible {
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    color: var(--text-primary);
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 4px;
    background-color: var(--primary-color);
    border-radius: 2px;
}

/* ============================================================================
   ABOUT SECTION
   ============================================================================ */

.about-content p {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.research-interests {
    margin: 2rem 0;
}

.research-interests h3,
.skills-section h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.research-interests ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 0.75rem;
}

.research-interests li {
    padding: 0.75rem 1rem;
    background-color: var(--bg-white);
    border-left: 3px solid var(--primary-color);
    border-radius: 0.25rem;
    box-shadow: var(--shadow-sm);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.skill-category {
    padding: 1.5rem;
    background-color: var(--bg-white);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-top: 3px solid transparent;
}

.skill-category:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-top-color: var(--primary-color);
}

.skill-category h4 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

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

/* ============================================================================
   RESEARCH SECTION
   ============================================================================ */

.research-grid {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.research-card {
    padding: 1.5rem;
    background-color: var(--bg-white);
    border-radius: 0.5rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-left: 3px solid transparent;
}

.research-card:hover {
    border-left-color: var(--primary-color);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    transform: translateX(5px);
}

.research-card h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.research-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ============================================================================
   PUBLICATIONS SECTION
   ============================================================================ */

.pub-category {
    margin-bottom: 3rem;
}

.pub-category h3 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.publication {
    display: grid;
    grid-template-columns: 80px 1fr;
    gap: 1.5rem;
    padding: 1.5rem;
    margin-bottom: 1rem;
    background-color: var(--bg-white);
    border-radius: 0.5rem;
    border-left: 3px solid var(--border-color);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.publication:hover {
    border-left-color: var(--primary-color);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    transform: translateX(5px);
}

.publication.highlight {
    border-left-color: var(--accent-color);
    background-color: #f0fdf4;
}

.pub-year {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 1.125rem;
}

.pub-title {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.pub-authors {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 0.25rem;
}

.pub-venue {
    color: var(--text-secondary);
    font-style: italic;
    font-size: 0.95rem;
}

.pub-award {
    color: var(--accent-color);
    font-weight: 600;
    font-size: 0.9rem;
    margin-top: 0.5rem;
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: #d1fae5;
    border-radius: 0.25rem;
    border-left: 3px solid var(--accent-color);
}

/* Gold award styling for John McCarthy Award */
.pub-award.gold {
    background-color: #FEF3C7;
    color: #92400E;
    border-left: 3px solid var(--accent-gold);
}

/* Blue award styling for Distinguished Artifact Award */
.pub-award.blue {
    background-color: #DBEAFE;
    color: #1E40AF;
    border-left: 3px solid var(--accent-blue);
}

/* ============================================================================
   TEACHING SECTION
   ============================================================================ */

.teaching-content {
    display: grid;
    gap: 2rem;
}

.teaching-section {
    margin-bottom: 3rem;
}

.teaching-card {
    padding: 2rem;
    background-color: var(--bg-white);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.teaching-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-3px);
}

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

.teaching-statement-section {
    background: linear-gradient(135deg, var(--bg-light) 0%, var(--bg-white) 100%);
    padding: 3rem;
    border-radius: 0.75rem;
    border: 2px solid var(--primary-color);
    box-shadow: var(--shadow-md);
    text-align: center;
}

.teaching-statement-section h3 {
    font-size: 1.75rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.teaching-statement-section .btn {
    margin-top: 0.5rem;
    padding: 1rem 2rem;
    font-size: 1.05rem;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
}

.course {
    margin-bottom: 1.5rem;
}

.course h4 {
    font-size: 1.125rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

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

.teaching-list {
    display: grid;
    gap: 1rem;
}

.teaching-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background-color: var(--bg-light);
    border-radius: 0.25rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.teaching-item strong {
    color: var(--text-primary);
}

.teaching-item span {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.teaching-card ul {
    list-style-position: inside;
    color: var(--text-secondary);
    line-height: 1.8;
}

.teaching-card ul li {
    margin-bottom: 0.5rem;
}

/* ============================================================================
   CONTACT SECTION
   ============================================================================ */

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

.contact-card {
    padding: 2rem;
    background-color: var(--bg-white);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.contact-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.contact-card h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.contact-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.contact-card a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
}

.contact-card a:hover {
    text-decoration: underline;
}

/* ============================================================================
   FOOTER
   ============================================================================ */

footer {
    background-color: var(--text-primary);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

footer p {
    margin: 0.25rem 0;
    opacity: 0.9;
}

/* ============================================================================
   RESPONSIVE DESIGN
   ============================================================================ */

@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-lg);
        padding: 2rem 0;
        gap: 1rem;
    }

    .nav-menu.active {
        left: 0;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-text h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1.25rem;
    }

    .hero-links {
        justify-content: center;
    }

    .section-title {
        font-size: 2rem;
    }

    .publication {
        grid-template-columns: 60px 1fr;
        gap: 1rem;
        padding: 1rem;
    }

    .teaching-item {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    #hero {
        padding: 6rem 0 3rem;
    }

    .hero-text h1 {
        font-size: 1.75rem;
    }

    .btn {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }
}