/* Global Styles */
:root {
    --primary-color: #15803d;
    /* Green 700 */
    --secondary-color: #14532d;
    /* Green 900 */
    --text-color: #1e293b;
    /* Slate 800 */
    --bg-color: #f8fafc;
    /* Slate 50 */
    --white: #ffffff;
    --gray: #64748b;
    /* Slate 500 */
    --dark-gray: #475569;
    /* Slate 600 */
    --font-main: 'Inter', sans-serif;
    --transition: all 0.3s ease;
}

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

body {
    font-family: var(--font-main);
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.6;
}

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

ul {
    list-style: none;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: 3rem;
}

h2 {
    font-size: 2.5rem;
}

h3 {
    font-size: 1.75rem;
}

p {
    margin-bottom: 1rem;
}

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

section {
    padding: 5rem 0;
}

/* Header */
header {
    background-color: var(--white);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    font-weight: 500;
    color: var(--dark-gray);
}

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

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(135deg, #dcfce7 0%, #f8fafc 100%);
    padding-top: 70px;
    /* Offset for fixed header */
}

.hero-content h1 {
    margin-bottom: 1rem;
    color: var(--text-color);
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--dark-gray);
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 0.5rem;
    font-weight: 600;
}

.btn:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    margin-left: 1rem;
}

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

/* Publications Section */
.publications {
    background-color: var(--bg-color);
}

.publications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.publication-category h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.publication-card {
    background-color: var(--white);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    margin-bottom: 1rem;
    border-left: 4px solid var(--primary-color);
    transition: var(--transition);
}

.publication-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

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

.pub-meta {
    color: var(--gray);
    font-size: 0.9rem;
    font-style: italic;
    margin-bottom: 0.5rem;
}

.pub-link {
    display: inline-block;
    margin-top: 0.5rem;
    color: var(--primary-color);
    font-weight: 500;
    font-size: 0.9rem;
}

.pub-link:hover {
    text-decoration: underline;
}

/* About Section */
.about {
    background-color: var(--white);
}

.about ul {
    margin-bottom: 2rem;
}

/* Experience Section */
.experience-item {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 0.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.experience-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

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

.date {
    color: var(--gray);
    font-size: 0.9rem;
}

/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: var(--white);
    padding: 2rem;
    border-radius: 0.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: var(--transition);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
}

/* Contact Section */
.contact {
    background-color: var(--white);
    text-align: center;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 2rem;
    font-size: 1.5rem;
}

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

/* Responsive */
@media (max-width: 768px) {
    h1 {
        font-size: 2.5rem;
    }

    .nav-links {
        display: none;
        /* Mobile menu to be implemented */
    }
}