:root {
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --accent-color: #2563eb;
    --secondary-text: #666666;
    --card-bg: #f8f9fa;
    --nav-bg: rgba(255, 255, 255, 0.9);
    --border-color: #e5e7eb;
    --transition-speed: 0.3s;
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --text-color: #e2e8f0;
    --accent-color: #60a5fa;
    --secondary-text: #94a3b8;
    --card-bg: #1e293b;
    --nav-bg: rgba(15, 23, 42, 0.9);
    --border-color: #334155;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color var(--transition-speed), color var(--transition-speed);
    overflow-x: hidden;
}

/* Utils */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 80px 0;
    scroll-margin-top: 70px;
}

.section-title {
    font-size: 2rem;
    margin-bottom: 40px;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    border-radius: 2px;
}

/* Header */
header {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    backdrop-filter: blur(10px);
    background-color: var(--nav-bg);
    border-bottom: 1px solid var(--border-color);
}

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

.logo {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--accent-color);
    text-decoration: none;
    transition: opacity 0.2s;
}

.logo:hover {
    opacity: 0.8;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.2s;
}

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

#theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-color);
    font-size: 1.2rem;
    transition: transform 0.3s;
}

#theme-toggle:hover {
    transform: rotate(15deg);
}

/* Hero Section */
.hero-section {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    position: relative;
    padding: 60px 0; /* Reduced padding, using margin for spacing */
    margin-top: 100px; /* Force push down below fixed header (70px) */
}

.hero-content {
    width: 100%;
    animation: fadeIn 1s ease-out;
}

.hero-avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    border: 4px solid var(--accent-color);
    margin-bottom: 20px;
    object-fit: cover;
}

.hero-name {
    font-size: 3.5rem;
    margin-bottom: 10px;
    font-weight: 800;
    background: linear-gradient(45deg, var(--accent-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-title {
    font-size: 1.5rem;
    color: var(--secondary-text);
    margin-bottom: 20px;
}

.hero-bio {
    max-width: 600px;
    margin: 0 auto 30px;
    font-size: 1.1rem;
    color: var(--secondary-text);
}

.scroll-down {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
    opacity: 0.7;
}

/* Profile Layout */
.profile-container {
    display: flex;
    gap: 60px;
    align-items: flex-start;
    padding-top: 40px;
}

.profile-sidebar {
    flex: 0 0 300px;
    text-align: left;
}

.profile-main {
    flex: 1;
    text-align: left;
}

.profile-avatar {
    width: 200px;
    height: 200px;
    border-radius: 12px;
    margin-bottom: 20px;
    object-fit: cover;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.profile-name {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 15px;
    background: linear-gradient(45deg, var(--accent-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.profile-affiliations {
    font-size: 0.6rem;
    color: var(--secondary-text);
    margin-bottom: 30px;
    line-height: 1.6;
}

.profile-affiliations div {
    margin-bottom: 5px;
}

.profile-contact-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.social-list-item {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-color);
    transition: color 0.2s;
}

.social-list-item:hover {
    color: var(--accent-color);
}

.social-icon-wrapper {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--card-bg);
    border-radius: 50%;
    border: 1px solid var(--border-color);
    transition: all 0.2s;
}

.social-list-item:hover .social-icon-wrapper {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.about-title {
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--text-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 10px;
    text-align: left;
}

.about-text p {
    font-size: 1.1rem;
    color: var(--text-color);
    line-height: 1.8;
    margin-bottom: 20px;
    text-align: justify;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .profile-container {
        flex-direction: column;
        gap: 30px;
        text-align: center;
    }
    
    .profile-sidebar {
        flex: auto;
        width: 100%;
        text-align: center;
    }
    
    .profile-contact-list {
        align-items: center;
    }
    
    .profile-avatar {
        margin: 0 auto 20px;
    }
}

/* News Section */
.news-container {
    border-left: 2px solid var(--border-color);
    padding-left: 30px;
}

.news-item {
    position: relative;
    margin-bottom: 30px;
}

.news-item::before {
    content: '';
    position: absolute;
    left: -36px;
    top: 6px;
    width: 10px;
    height: 10px;
    background: var(--accent-color);
    border-radius: 50%;
}

.news-date {
    font-size: 0.9rem;
    color: var(--accent-color);
    font-weight: 600;
    margin-bottom: 5px;
}

/* Publications */
.papers-grid {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.paper-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 25px;
    border: 1px solid var(--border-color);
    transition: transform 0.3s, box-shadow 0.3s;
    display: flex;
    gap: 20px;
}

.paper-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.paper-image {
    width: 120px;
    height: 120px;
    object-fit: cover;
    border-radius: 8px;
    flex-shrink: 0;
    display: none; /* Hidden on mobile by default */
}

@media (min-width: 768px) {
    .paper-image {
        display: block;
    }
}

.paper-content {
    flex: 1;
}

.paper-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-color);
}

.paper-authors {
    color: var(--secondary-text);
    margin-bottom: 8px;
    font-size: 0.95rem;
}

.paper-venue {
    font-weight: 600;
    color: var(--accent-color);
    margin-bottom: 12px;
    display: inline-block;
    background: rgba(37, 99, 235, 0.1);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.85rem;
}

.paper-links a {
    text-decoration: none;
    color: var(--text-color);
    border: 1px solid var(--border-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-right: 10px;
    transition: all 0.2s;
}

.paper-links a:hover {
    background: var(--text-color);
    color: var(--bg-color);
}

/* Contact / Footer */
.footer-section {
    text-align: center;
    background: var(--card-bg);
    padding: 60px 0 30px;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 30px;
}

.social-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--bg-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-color);
    text-decoration: none;
    font-size: 1.5rem;
    border: 1px solid var(--border-color);
    transition: transform 0.2s, color 0.2s;
}

.social-btn:hover {
    transform: scale(1.1);
    color: var(--accent-color);
    border-color: var(--accent-color);
}

.copyright {
    color: var(--secondary-text);
    font-size: 0.9rem;
}

/* Cursor Glow Effect */
.cursor-glow {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(37, 99, 235, 0.15) 0%, rgba(255, 255, 255, 0) 70%);
    position: fixed;
    top: 0;
    left: 0;
    pointer-events: none;
    z-index: -1;
    transform: translate(-50%, -50%);
    display: none; /* Only for desktop */
}

@media (pointer: fine) {
    .cursor-glow {
        display: block;
    }
}

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

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translate(-50%, 0); }
    40% { transform: translate(-50%, -10px); }
    60% { transform: translate(-50%, -5px); }
}

/* Mobile Responsive Adjustments */
@media (max-width: 768px) {
    .hero-name {
        font-size: 2.5rem;
    }
    
    .nav-links {
        display: none; /* Simplified for MVP, usually needs a hamburger menu */
    }
}