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

:root {
    --color-primary: #1a365d;
    --color-primary-light: #2c5282;
    --color-accent: #c53030;
    --color-text: #2d3748;
    --color-text-light: #4a5568;
    --color-bg: #ffffff;
    --color-bg-alt: #f7fafc;
    --color-border: #e2e8f0;
    --font-sans: 'Source Sans Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Source Serif Pro', Georgia, 'Times New Roman', serif;
    --max-width: 1100px;
    --transition: 0.2s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
}

/* Typography */
h1, h2, h3, h4 {
    font-family: var(--font-serif);
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-primary);
}

h1 {
    font-size: 2.75rem;
}

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

h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background-color: var(--color-accent);
    margin-top: 0.5rem;
}

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

p {
    margin-bottom: 1rem;
}

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

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

/* Layout */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 5rem 0;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    padding: 1rem 0;
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

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

.nav-links a {
    color: var(--color-text);
    font-size: 0.95rem;
    font-weight: 500;
    transition: color var(--transition);
}

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

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: white;
    padding: 10rem 1.5rem 6rem;
    text-align: center;
}

.hero-content {
    max-width: 700px;
    margin: 0 auto;
}

.hero h1 {
    color: white;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.5rem;
    font-weight: 300;
    margin-bottom: 0.25rem;
    opacity: 0.95;
}

.affiliation {
    font-size: 1.1rem;
    opacity: 0.85;
    margin-bottom: 2rem;
}

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all var(--transition);
    cursor: pointer;
    background-color: white;
    color: var(--color-primary);
}

.btn:hover {
    background-color: var(--color-bg-alt);
    color: var(--color-primary);
    transform: translateY(-1px);
}

.btn-outline {
    background-color: transparent;
    border: 2px solid white;
    color: white;
}

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

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    background-color: var(--color-primary);
    color: white;
}

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

/* Research Grid */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.research-item {
    padding: 1.5rem;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.research-item h3 {
    color: var(--color-primary);
}

.research-item p {
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* Software Cards */
.software-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.software-card {
    background-color: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 2rem;
}

.software-card h3 {
    font-family: 'Courier New', monospace;
    font-size: 1.5rem;
    color: var(--color-primary);
}

.software-tagline {
    font-style: italic;
    color: var(--color-text-light);
    margin-bottom: 1rem;
}

.software-card ul {
    margin: 1rem 0 1.5rem 1.25rem;
    color: var(--color-text-light);
}

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

/* Publications */
.section-note {
    font-size: 1.1rem;
    color: var(--color-text-light);
    margin-bottom: 2rem;
}

.publications-list {
    border-left: 3px solid var(--color-border);
    padding-left: 1.5rem;
}

.publication-item {
    margin-bottom: 1.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--color-border);
}

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

.publication-title {
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.25rem;
}

.publication-authors {
    color: var(--color-text-light);
    font-size: 0.95rem;
}

.publication-venue {
    font-style: italic;
    color: var(--color-text-light);
    font-size: 0.9rem;
}

.placeholder-text {
    color: var(--color-text-light);
    font-style: italic;
}

.publications-list h3 {
    font-size: 1.1rem;
    color: var(--color-primary);
    margin-top: 1.5rem;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.publications-list h3:first-child {
    margin-top: 0;
}

.publication-items {
    list-style: none;
    margin: 0;
    padding: 0;
}

.publication-items li {
    margin-bottom: 1.25rem;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid var(--color-border);
    line-height: 1.6;
    color: var(--color-text-light);
}

.publication-items li:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.publication-items strong {
    color: var(--color-text);
}

.publication-items em {
    color: var(--color-text);
}

/* Teaching Section */
.teaching-content h3 {
    font-size: 1.1rem;
    color: var(--color-primary);
    margin-top: 2rem;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.teaching-content h3:first-child {
    margin-top: 0;
}

.teaching-list {
    list-style: none;
    margin: 0;
    padding: 0;
    border-left: 3px solid var(--color-border);
    padding-left: 1.5rem;
}

.teaching-list li {
    margin-bottom: 1.25rem;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid var(--color-border);
}

.teaching-list li:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.course-name {
    font-weight: 600;
    color: var(--color-text);
    display: block;
}

.course-term {
    color: var(--color-text-light);
    font-size: 0.9rem;
    font-style: italic;
}

.course-description {
    color: var(--color-text-light);
    font-size: 0.95rem;
    margin-top: 0.5rem;
    margin-bottom: 0;
}

/* Media Section */
.media-content {
    max-width: 800px;
    margin: 0 auto;
}

.video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* Contact Section */
.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.contact-item h3 {
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-light);
    margin-bottom: 0.5rem;
}

.contact-item p {
    margin-bottom: 0;
}

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

footer p {
    margin: 0;
    opacity: 0.8;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    .subtitle {
        font-size: 1.25rem;
    }

    .nav-links {
        display: none;
    }

    .hero {
        padding: 8rem 1.5rem 4rem;
    }

    .section {
        padding: 3rem 0;
    }

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

    .contact-info {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-links {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 250px;
        text-align: center;
    }
}