/* Global Variables & Reset */
:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent: #d97706;
    /* Amber/Gold */
    --accent-glow: rgba(217, 119, 6, 0.2);
    --font-heading: 'Playfair Display', serif;
    --font-body: 'Inter', sans-serif;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --section-padding: 6rem 1rem;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-body);
    line-height: 1.6;
    overflow-x: hidden;
}

h1,
h2,
h3,
h4 {
    font-family: var(--font-heading);
    color: #fff;
    font-weight: 700;
}

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

ul {
    list-style: none;
}

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

/* Utilities */
.btn-primary {
    background-color: var(--accent);
    color: #fff;
    padding: 0.8rem 2rem;
    border-radius: 50px;
    font-weight: 600;
    letter-spacing: 0.5px;
    box-shadow: 0 4px 15px var(--accent-glow);
}

.btn-primary:hover {
    background-color: #b45309;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--accent-glow);
}

.btn-secondary {
    border: 1px solid var(--text-secondary);
    color: var(--text-primary);
    padding: 0.8rem 2rem;
    border-radius: 50px;
    font-weight: 500;
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.btn-text {
    color: var(--text-primary);
    font-weight: 600;
    margin-left: 1.5rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-text:hover {
    color: var(--accent);
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: padding 0.3s;
}

.navbar.scrolled {
    padding: 1rem 0;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}

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

.logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.logo .dot {
    color: var(--accent);
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    align-items: center;
}

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

.nav-links a:hover,
.nav-links a.active {
    color: #fff;
}

.btn-outline {
    border: 1px solid var(--accent);
    color: var(--accent) !important;
    padding: 0.5rem 1.2rem;
    border-radius: 4px;
}

.btn-outline:hover {
    background: var(--accent);
    color: #fff !important;
}

/* Mobile Menu */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    z-index: 1001;
}

.mobile-menu-btn .bar {
    display: block;
    width: 25px;
    height: 3px;
    background-color: #fff;
    margin: 5px 0;
    transition: var(--transition);
}

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    margin-bottom: 2rem;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('abstract_geometric_network_background.png') no-repeat center center/cover;
    opacity: 0.4;
    z-index: -2;
    animation: zoomEffect 20s infinite alternate;
}

@keyframes zoomEffect {
    from {
        transform: scale(1);
    }

    to {
        transform: scale(1.1);
    }
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, transparent 0%, var(--bg-color) 90%);
    z-index: -1;
}

.hero-content {
    max-width: 800px;
    padding-top: 4rem;
}

.hero h1 {
    font-size: 4.5rem;
    line-height: 1.1;
    margin-bottom: 1rem;
    background: linear-gradient(to right, #fff, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero h2 {
    font-family: var(--font-body);
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--accent);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
}

/* Hero Highlights */
.hero-highlights {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.highlight-item {
    background: rgba(255, 255, 255, 0.08);
    backdrop-filter: blur(5px);
    padding: 0.8rem 1.5rem;
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    align-items: center;
    gap: 0.8rem;
    color: #e2e8f0;
    font-size: 0.95rem;
    transition: var(--transition);
}

.highlight-item:hover {
    background: rgba(255, 255, 255, 0.12);
    transform: translateY(-2px);
    border-color: var(--accent);
}

.accent-icon {
    color: var(--accent);
}

.highlight-link {
    color: #fff;
    text-decoration: underline;
    text-decoration-color: var(--accent);
    text-underline-offset: 4px;
}

.highlight-link:hover {
    color: var(--accent);
}


/* About Section */
.section {
    padding: var(--section-padding);
}

.section-header {
    margin-bottom: 4rem;
}

.section-header .subtitle {
    display: block;
    color: var(--accent);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 0.5rem;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.line {
    width: 60px;
    height: 3px;
    background: var(--accent);
}

.about-grid {
    display: grid;
    grid-template-columns: 350px 1fr;
    gap: 4rem;
    align-items: center;
}

.about-image-container {
    padding: 1rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    border-bottom: 4px solid var(--accent);
    transition: transform 0.5s ease;
}

.about-image-container:hover {
    transform: scale(1.02);
}

.profile-image {
    width: 100%;
    height: auto;
    border-radius: 10px;
    display: block;
    filter: brightness(0.95);
    transition: var(--transition);
}

.profile-image:hover {
    filter: brightness(1.05);
}

.about-text p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.interests-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-top: 2rem;
}

.tag {
    background: rgba(255, 255, 255, 0.05);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s;
}

.tag:hover {
    background: rgba(217, 119, 6, 0.2);
    border-color: var(--accent);
}

/* Research Section */
.research-section {
    background: linear-gradient(to bottom, var(--bg-color), #0b1120);
}

.research-tabs {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.tab-btn {
    background: transparent;
    border: 1px solid var(--text-secondary);
    color: var(--text-secondary);
    padding: 0.7rem 1.5rem;
    border-radius: 50px;
    cursor: pointer;
    font-family: var(--font-body);
    font-weight: 500;
    transition: var(--transition);
}

.tab-btn:hover,
.tab-btn.active {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(217, 119, 6, 0.1);
}

.tab-btn.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
    box-shadow: 0 0 15px var(--accent-glow);
}

.research-list {
    display: none;
    animation: fadeIn 0.5s ease-out;
}

.research-list.active {
    display: grid;
    gap: 2rem;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.tab-header {
    color: white;
    margin: 2rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.article-link {
    display: block;
}

.pub-card {
    display: grid;
    grid-template-columns: 120px 1fr;
    gap: 2rem;
    padding: 2rem;
    background: rgba(30, 41, 59, 0.5);
    border-radius: 8px;
    border-left: 3px solid transparent;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.article-link .pub-card:hover {
    background: var(--card-bg);
    border-left-color: var(--accent);
    transform: translateX(10px);
    box-shadow: -5px 5px 20px rgba(0, 0, 0, 0.3);
}

.pub-card:hover {
    background: var(--card-bg);
}

.pub-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--text-secondary);
    opacity: 0.5;
}

.pub-year {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    color: var(--text-secondary);
    font-weight: 700;
    opacity: 0.5;
    text-align: right;
}

.pub-content h3 {
    font-family: var(--font-body);
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    line-height: 1.4;
    color: #fff;
}

.small-icon {
    font-size: 0.8rem;
    vertical-align: middle;
    margin-left: 0.5rem;
    opacity: 0.7;
    color: var(--accent);
}

.pub-journal {
    color: var(--accent);
    font-style: italic;
    margin-bottom: 0.5rem;
    display: inline-block;
}

.pub-authors {
    font-size: 0.9rem;
    color: #ccc;
    opacity: 0.9;
    margin-bottom: 0.8rem;
}

.pub-abstract {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.research-list.active .pub-card:nth-child(1) {
    animation: slideIn 0.5s ease-out 0.1s backwards;
}

.research-list.active .pub-card:nth-child(2) {
    animation: slideIn 0.5s ease-out 0.2s backwards;
}

.research-list.active .pub-card:nth-child(3) {
    animation: slideIn 0.5s ease-out 0.3s backwards;
}

.research-list.active .pub-card:nth-child(4) {
    animation: slideIn 0.5s ease-out 0.4s backwards;
}

.research-list.active .pub-card:nth-child(5) {
    animation: slideIn 0.5s ease-out 0.5s backwards;
}

.research-list.active .pub-card:nth-child(6) {
    animation: slideIn 0.5s ease-out 0.6s backwards;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.ongoing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.ongoing-card {
    background: rgba(255, 255, 255, 0.03);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: var(--transition);
}

.ongoing-card:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--accent);
    transform: translateY(-5px);
}

.ongoing-card h4 {
    font-size: 1.1rem;
    margin-bottom: 0.8rem;
    line-height: 1.4;
}

/* Implicit Progress Bar */
.ongoing-card {
    position: relative;
    overflow: hidden;
}

.progress-line {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), #f59e0b);
    width: 0%;
    transition: width 1s ease-out;
    opacity: 0;
}

.ongoing-card:hover .progress-line {
    opacity: 1;
}

/* Specific Widths for Progress Bars on Hover */
.ongoing-card[data-progress="5"]:hover .progress-line {
    width: 5%;
}

.ongoing-card[data-progress="10"]:hover .progress-line {
    width: 10%;
}

.ongoing-card[data-progress="20"]:hover .progress-line {
    width: 20%;
}

.ongoing-card[data-progress="30"]:hover .progress-line {
    width: 30%;
}

.ongoing-card[data-progress="40"]:hover .progress-line {
    width: 40%;
}

.ongoing-card[data-progress="50"]:hover .progress-line {
    width: 50%;
}

.ongoing-card[data-progress="60"]:hover .progress-line {
    width: 60%;
}

.ongoing-card[data-progress="70"]:hover .progress-line {
    width: 70%;
}

.ongoing-card[data-progress="80"]:hover .progress-line {
    width: 80%;
}

.ongoing-card[data-progress="90"]:hover .progress-line {
    width: 90%;
}

.ongoing-card[data-progress="100"]:hover .progress-line {
    width: 100%;
}

/* Teaching Section */
.teaching-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    margin-bottom: 4rem;
}

.university-column h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.university-column h3 i {
    color: var(--accent);
}

.course-list li {
    padding: 0.8rem 0;
    color: var(--text-secondary);
    border-bottom: 1px solid rgba(255, 255, 255, 0.03);
    padding-left: 1.5rem;
    position: relative;
    transition: var(--transition);
}

.course-list li:before {
    content: '•';
    color: var(--accent);
    position: absolute;
    left: 0;
}

.course-list li:hover {
    color: #fff;
    padding-left: 2rem;
}

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

.quote-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    position: relative;
    transition: transform 0.3s ease;
}

.quote-card:hover {
    transform: translateY(-5px);
}

.quote-icon {
    font-size: 1.5rem;
    color: var(--accent);
    opacity: 0.5;
    margin-bottom: 1rem;
}

.quote-card p {
    color: var(--text-secondary);
    font-style: italic;
    margin-bottom: 1.5rem;
}

.quote-card cite {
    display: block;
    color: #fff;
    font-weight: 600;
    font-size: 0.9rem;
}

/* Conference Section */
.conference-section {
    background: linear-gradient(to top, var(--bg-color), rgba(15, 23, 42, 0.5));
    padding: 3rem 1rem;
}

.conference-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 1.5rem;
    overflow-x: visible;
    /* Remove scroll */
    padding-bottom: 0;
    margin: 0;
}

.conf-card {
    background: rgba(30, 41, 59, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    padding: 1.25rem;
    position: relative;
    transition: var(--transition);
    display: flex;
    gap: 1.5rem;
    align-items: center;
    /* Center vertically */
    min-width: 0;
    /* Allow shrinking */
}

.conf-card:hover {
    background: var(--card-bg);
    border-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.conf-logo-container {
    width: 60px;
    height: 60px;
    background: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 5px;
    flex-shrink: 0;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.conf-logo {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.conf-details {
    flex: 1;
}

.conf-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.3rem;
    font-size: 0.8rem;
    color: var(--accent);
    font-weight: 600;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.conf-name {
    font-size: 1rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 0.2rem;
    line-height: 1.2;
}

.conf-paper {
    font-style: italic;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0.3rem;
}

.conf-loc {
    font-size: 0.8rem;
    color: var(--text-secondary);
    opacity: 0.6;
}

/* Contact Section */
.contact-section {
    padding-bottom: 4rem;
}

.contact-box {
    background: linear-gradient(135deg, var(--card-bg), #182236);
    padding: 4rem 2rem;
    border-radius: 20px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.contact-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 2rem;
    margin-top: 3rem;
}

.contact-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.8rem;
    background: rgba(255, 255, 255, 0.03);
    padding: 1.5rem;
    border-radius: 12px;
    min-width: 150px;
    transition: var(--transition);
}

.contact-item:hover {
    background: rgba(255, 255, 255, 0.08);
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.contact-item i {
    font-size: 2rem;
    color: var(--accent);
}

.contact-item span {
    font-size: 0.95rem;
    font-weight: 500;
}

.contact-item.special {
    border: 1px solid var(--accent);
}

/* Footer */
footer {
    padding: 2rem 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.fade-in-up {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s forwards;
}

.delay-1 {
    animation-delay: 0.2s;
}

.delay-2 {
    animation-delay: 0.4s;
}

.delay-3 {
    animation-delay: 0.6s;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--bg-color);
        flex-direction: column;
        justify-content: center;
        padding: 2rem;
        text-align: center;
        z-index: 999;
    }

    .nav-links a {
        font-size: 1.5rem;
        margin: 1rem 0;
    }

    .nav-links.active {
        display: flex;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero h1 {
        font-size: 2.8rem;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .about-image-container {
        max-width: 280px;
        margin: 0 auto;
    }

    .pub-card {
        grid-template-columns: 1fr;
        gap: 0.5rem;
        padding: 1.5rem;
        text-align: left;
    }

    .pub-year {
        text-align: left;
        font-size: 1.2rem;
        margin-bottom: 0.5rem;
        color: var(--accent);
        opacity: 1;
    }

    .teaching-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .section {
        padding: 4rem 1.5rem;
    }

    /* Highlights on mobile */
    .hero-highlights {
        justify-content: center;
    }
}