:root {
    --bg-color: #fafafa;
    --text-color: #1e293b;
    --text-light: #64748b;
    --heading-color: #312e81;
    --accent-color: #0ea5e9;
    --accent-hover: #2563eb;
    --accent-secondary: #e11d48;
    --border-color: #e2e8f0;
    
    --max-width: 800px;
    --spacing: 5rem;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--bg-color);
    background-image: 
        radial-gradient(circle at 0% 0%, rgba(14, 165, 233, 0.08) 0%, transparent 40%), 
        radial-gradient(circle at 100% 100%, rgba(225, 29, 72, 0.06) 0%, transparent 40%);
    background-attachment: fixed;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
    font-family: 'Playfair Display', serif;
    color: var(--heading-color);
    line-height: 1.3;
    letter-spacing: -0.01em;
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

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

/* Header & Nav */
.header {
    padding: 1.2rem 0;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    background: rgba(250, 250, 250, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: all 0.3s ease;
}

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

.logo {
    font-family: 'Playfair Display', serif;
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: -0.01em;
    background: linear-gradient(135deg, var(--heading-color), var(--accent-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    transition: opacity 0.3s ease;
}

.logo:hover {
    opacity: 0.8;
}

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

.nav-list a {
    color: var(--text-light);
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    position: relative;
    padding-bottom: 0.3rem;
}

.nav-list a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-color), var(--accent-secondary));
    transition: width 0.3s ease;
    border-radius: 2px;
}

.nav-list a:hover,
.nav-list a.active {
    color: var(--heading-color);
    text-decoration: none;
}

.nav-list a:hover::after,
.nav-list a.active::after {
    width: 100%;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
}

/* Sections */
.section {
    padding: var(--spacing) 0;
    border-bottom: 1px solid var(--border-color);
}

.section:last-of-type {
    border-bottom: none;
}

.section-title {
    font-size: 2.2rem;
    margin-bottom: 2.5rem;
    font-weight: 600;
    font-style: italic;
    color: var(--heading-color);
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    border-radius: 2px;
    background: linear-gradient(90deg, var(--accent-color), var(--accent-secondary));
}

/* Hero Section */
.hero {
    display: flex;
    align-items: center;
    gap: 3rem;
    padding: 5rem 0;
}

.hero-text {
    flex: 1;
}

.hero-text h1 {
    font-size: 3.5rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--heading-color), var(--accent-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-text h2 {
    font-size: 1.25rem;
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    color: var(--text-light);
    margin-bottom: 1.5rem;
    letter-spacing: 0.01em;
}

.hero-text p {
    font-size: 1.1rem;
    color: var(--text-color);
    margin-bottom: 2rem;
    max-width: 600px;
}

.hero-side {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    flex-shrink: 0;
}

.hero-image img {
    width: 180px;
    height: 180px;
    border-radius: 8px;
    object-fit: cover;
    border: 6px solid #ffffff;
    box-shadow: 0 15px 35px rgba(0,0,0,0.06);
    transition: transform 0.4s ease;
}

.hero-image img:hover {
    transform: translateY(-5px);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.8rem;
    background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
    color: #ffffff;
    border-radius: 3px;
    font-weight: 500;
    font-family: 'Inter', sans-serif;
    letter-spacing: 0.02em;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    border: none;
    box-shadow: 0 4px 10px rgba(14, 165, 233, 0.2);
}

.btn:hover {
    background: linear-gradient(135deg, var(--accent-hover), var(--heading-color));
    color: #ffffff;
    text-decoration: none;
    box-shadow: 0 6px 15px rgba(14, 165, 233, 0.3);
    transform: translateY(-2px);
}

.btn-outline {
    background-color: transparent;
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.btn-outline:hover {
    background-color: var(--bg-color);
    border-color: var(--accent-color);
    color: var(--accent-color);
    box-shadow: none;
}

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

/* General Lists (About, Education) */
.list-item {
    margin-bottom: 1.5rem;
}

.list-item h4 {
    font-family: 'Inter', sans-serif;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.list-item .meta {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    display: block;
}

.list-item p {
    color: var(--text-color);
}

/* Teaching Courses Resources */
.course-resources-container {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
    margin-top: 1rem;
}

.course-resource-group {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.resource-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    min-width: 140px;
}

.resource-label i {
    color: var(--accent-color);
}

.resource-link {
    display: inline-flex;
    align-items: center;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-light);
    transition: all 0.2s ease;
}

.resource-link:hover {
    color: var(--accent-secondary);
    text-decoration: underline;
}

/* Publications */
.pub-item {
    margin-bottom: 2rem;
}

.pub-item h3 {
    font-family: 'Inter', sans-serif;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.pub-item .authors {
    color: var(--text-color);
    margin-bottom: 0.25rem;
}

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

.pub-item .links {
    margin-top: 0.25rem;
    font-size: 0.9rem;
}

.pub-category {
    margin-bottom: 1.5rem;
    font-size: 1.25rem;
    color: var(--text-light);
    margin-top: 3rem;
}

.pub-category:first-of-type {
    margin-top: 0;
}

/* Contact Side Icons */
.contact-side {
    display: flex;
    gap: 1.2rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 0.5rem;
}

.contact-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
    font-size: 1.3rem;
}

.contact-icon:hover {
    color: var(--accent-secondary);
    transform: translateY(-3px) scale(1.1);
}

/* Footer */
.footer {
    padding: 4rem 0 3rem;
    text-align: center;
    font-size: 0.95rem;
    font-weight: 500;
}

.footer p {
    background: linear-gradient(90deg, var(--accent-color), var(--accent-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

/* Responsive */
@media (max-width: 768px) {
    .hero {
        flex-direction: column-reverse;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-text h1 {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .nav-list {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-color);
        padding: 1rem;
        border-bottom: 1px solid var(--border-color);
        text-align: center;
    }
    
    .nav-list.active {
        display: flex;
    }
    
    .mobile-menu-btn {
        display: block;
    }
}