:root {
    --bg-color: #0d1117;
    --card-bg: rgba(22, 27, 34, 0.6);
    --border-color: rgba(255, 255, 255, 0.08);
    --text-primary: #f0f6fc;
    --text-secondary: #8b949e;
    --accent: #58a6ff;
    --accent-glow: rgba(88, 166, 255, 0.4);
    --nav-bg: rgba(13, 17, 23, 0.85);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: var(--nav-bg);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: linear-gradient(90deg, var(--text-primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

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

nav ul li a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    transition: color 0.3s;
    cursor: pointer;
}

nav ul li a:hover, nav ul li a.active {
    color: var(--accent);
}

#content {
    padding-top: 60px;
    flex-grow: 1;
}

.section-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 6rem 2rem;
}

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Hero Section with Image Grid */
.hero {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    min-height: 80vh;
}

@media (max-width: 768px) {
    .hero {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .hero-content {
        order: 1;
    }
    .hero-image {
        order: 2;
        margin-top: 2rem;
        margin-bottom: 2rem;
    }
}

.hero h1 {
    font-size: 4.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.1;
    background: linear-gradient(135deg, #ffffff 30%, #58a6ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero h2 {
    font-size: 1.8rem;
    font-weight: 400;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin-bottom: 2.5rem;
}

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

@media (max-width: 768px) {
    .hero .cta-buttons {
        justify-content: center;
    }
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.hero-image::before {
    content: '';
    position: absolute;
    width: 350px;
    height: 350px;
    background: var(--accent);
    filter: blur(80px);
    opacity: 0.2;
    border-radius: 50%;
    z-index: 0;
}

.hero-image img {
    width: 350px;
    height: 350px;
    object-fit: cover;
    border-radius: 30px;
    border: 2px solid var(--border-color);
    z-index: 1;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    transition: transform 0.3s ease;
}

.hero-image img:hover {
    transform: translateY(-10px) scale(1.02);
}

.btn {
    padding: 0.8rem 1.8rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    border: none;
    box-shadow: 0 0 15px var(--accent-glow);
}

.btn-primary:hover {
    box-shadow: 0 0 25px var(--accent-glow);
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: rgba(88, 166, 255, 0.1);
    border-color: var(--accent);
    transform: translateY(-2px);
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    position: relative;
    display: inline-block;
    color: var(--text-primary);
}

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

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    backdrop-filter: blur(5px);
    transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
    text-decoration: none;
    color: inherit;
    display: block;
}

.card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.card h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.3rem;
}

.card p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.card .meta {
    font-size: 0.85rem;
    color: var(--accent);
    margin-bottom: 1rem;
    display: block;
    font-weight: 600;
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.tag {
    padding: 0.3rem 0.8rem;
    background: rgba(88, 166, 255, 0.1);
    color: var(--accent);
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    border: 1px solid rgba(88, 166, 255, 0.2);
}

footer {
    background: #090c10;
    padding: 3rem 5%;
    border-top: 1px solid var(--border-color);
    text-align: center;
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

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

.socials {
    display: flex;
    gap: 1.5rem;
}

.socials a {
    color: var(--text-secondary);
    font-size: 1.5rem;
    transition: color 0.3s, transform 0.3s;
}

.socials a:hover {
    color: var(--accent);
    transform: translateY(-3px) scale(1.1);
}

/* Timeline */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background: var(--border-color);
    top: 0;
    bottom: 0;
    left: 20px;
    margin-left: -1px;
}

.timeline-item {
    padding: 10px 40px 40px 50px;
    position: relative;
    background: inherit;
    width: 100%;
}

.timeline-item::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    right: auto;
    background: var(--bg-color);
    border: 3px solid var(--accent);
    top: 15px;
    border-radius: 50%;
    z-index: 1;
    left: 12px;
}

.timeline-content {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.timeline-content:hover {
    border-color: var(--accent);
}

.timeline-content h3 {
    margin-bottom: 0.2rem;
}

.timeline-content h4 {
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: 1rem;
}

.about-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
}

@media (max-width: 1000px) {
    .about-grid {
        grid-template-columns: 1fr;
    }
}

/* Publications list */
.pub-item {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    transition: background 0.3s;
}

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

.pub-item:hover {
    background: rgba(255, 255, 255, 0.02);
}

.pub-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.pub-authors {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.pub-venue {
    color: var(--accent);
    font-size: 0.85rem;
}

/* --- Comprehensive Mobile Responsiveness natively --- */
@media (max-width: 900px) {
    nav {
        flex-direction: column;
        padding: 1rem;
        gap: 0.8rem;
    }
    nav ul {
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
    }
    .hero h1 {
        font-size: 3.2rem;
    }
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.8rem;
    margin-top: 1.5rem;
    width: 100%;
}

@media (max-width: 650px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .hero-image img, .hero-image::before {
        width: 260px;
        height: 260px;
    }
}

@media (max-width: 450px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
    .hero h1 {
        font-size: 2.6rem;
    }
}