@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;600;700&display=swap');

:root {
    /* Warm Dark Theme */
    --bg-color: #1c1917;
    --surface-color: #292524;
    --accent-color: #fb923c;
    /* Shifted to Orange/Amber for "Warm" feel */
    --accent-secondary: #f97316;
    --accent-glow: rgba(251, 146, 60, 0.4);
    --text-primary: #fafaf9;
    --text-secondary: #a8a29e;
    --glass-bg: rgba(28, 25, 23, 0.85);
    --glass-border: rgba(255, 255, 255, 0.1);
    --transition: all 0.4s cubic-bezier(0.23, 1, 0.32, 1);
}

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

html {
    scroll-behavior: smooth;
}

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

/* Typography */
h1,
h2,
h3 {
    font-weight: 700;
    line-height: 1.2;
}

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

ul {
    list-style: none;
}

/* Layout */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    padding: 100px 0;
}

/* Navigation */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--glass-border);
    padding: 1.5rem 0;
}

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

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

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

.nav-links a {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 180px 0 100px;
    background-image: linear-gradient(to bottom, transparent, rgba(28, 25, 23, 0.95)), url('images/IMG_4067.JPEG');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    position: relative;
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 4rem;
}

.hero-text {
    flex: 1;
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

.profile-pic {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--surface-color);
    box-shadow: 0 0 30px rgba(59, 130, 246, 0.3);
    transition: var(--transition);
}

.profile-pic:hover {
    transform: scale(1.05);
    box-shadow: 0 0 50px rgba(59, 130, 246, 0.5);
}

.hero h1 {
    font-size: clamp(3rem, 6vw, 4.5rem);
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #fff 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Research Images */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin: 1rem 0;
}

.research-img {
    width: 100%;
    height: 180px;
    object-fit: cover;
    border-radius: 8px;
    border: 1px solid var(--glass-border);
    transition: var(--transition);
}

.research-img:hover {
    transform: scale(1.03);
    border-color: var(--accent-color);
}

@media (max-width: 768px) {
    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
    }

    .profile-pic {
        width: 200px;
        height: 200px;
    }
}

.hero p {
    font-size: 1.35rem;
    color: #ffffff;
    max-width: 600px;
    margin-bottom: 2rem;
    font-weight: 500;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.hero-btns {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-top: 2rem;
}

.btn {
    display: inline-block;
    padding: 0.8rem 1.8rem;
    background-color: var(--accent-color);
    color: #fff;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.95rem;
    box-shadow: 0 4px 14px 0 var(--accent-glow);
    transition: var(--transition);
    border: 1px solid transparent;
}

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    box-shadow: none;
}

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

.btn-outline:hover {
    border-color: var(--accent-color);
    background-color: rgba(251, 146, 60, 0.05);
    box-shadow: none;
}

/* Sections General */
.section-title {
    font-size: 2rem;
    margin-bottom: 3rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 40px;
    height: 4px;
    background-color: var(--accent-color);
    border-radius: 2px;
}

/* Sub Navigation */
.sub-nav {
    display: flex;
    gap: 1.5rem;
    margin-top: 1rem;
}

.sub-nav-link {
    font-size: 0.95rem;
    color: var(--text-secondary);
    position: relative;
    padding-bottom: 0.2rem;
    cursor: pointer;
    transition: var(--transition);
}

.sub-nav-link:hover,
.sub-nav-link.active {
    color: var(--accent-color);
}

.sub-nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--accent-color);
}

/* Cards */
.card {
    background: var(--surface-color);
    border: 1px solid var(--glass-border);
    padding: 2rem;
    border-radius: 16px;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.card-header h3 {
    font-size: 1.25rem;
    flex: 1;
}

.metrics {
    display: flex;
    gap: 0.5rem;
    flex-shrink: 0;
}

.metric-chip {
    padding: 0.25rem 0.7rem;
    background: rgba(96, 165, 250, 0.1);
    border: 1px solid rgba(96, 165, 250, 0.2);
    border-radius: 100px;
    font-size: 0.7rem;
    color: var(--accent-color);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

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

/* Publications Grid */
.pub-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

.pub-item {
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--glass-border);
}

.pub-banner {
    width: 100%;
    height: 120px;
    object-fit: cover;
    border-radius: 4px;
    margin-bottom: 1rem;
    opacity: 0.8;
}

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

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

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

.pub-doi {
    color: var(--accent-color);
    font-size: 0.8rem;
    margin-top: 0.5rem;
    display: inline-block;
}

/* Experience / Education Timeline */
.timeline {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.timeline-item {
    position: relative;
    padding-left: 2rem;
    border-left: 2px solid var(--glass-border);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -7px;
    top: 0;
    width: 12px;
    height: 12px;
    background: var(--accent-color);
    border-radius: 50%;
}

.timeline-date {
    font-size: 0.85rem;
    color: var(--accent-color);
    font-weight: 600;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}

.timeline-content h3 {
    margin-bottom: 0.25rem;
}

.timeline-content span {
    color: var(--text-secondary);
    font-size: 0.9rem;
    display: block;
    margin-bottom: 1rem;
}

/* Skills */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1.5rem;
}

.skill-category h4 {
    margin-bottom: 1rem;
    color: var(--accent-color);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.skill-tag {
    padding: 0.4rem 1rem;
    background: var(--surface-color);
    border: 1px solid var(--glass-border);
    border-radius: 100px;
    font-size: 0.85rem;
}

/* Footer */
footer {
    padding: 4rem 0;
    text-align: center;
    border-top: 1px solid var(--glass-border);
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 2.5rem;
    margin-bottom: 2rem;
}

.social-icon {
    width: 28px;
    height: 28px;
    opacity: 0.6;
    transition: var(--transition);
}

.social-links a:hover .social-icon {
    opacity: 1;
    transform: translateY(-5px) scale(1.1);
    filter: drop-shadow(0 0 8px var(--accent-glow));
}

.footer-text {
    color: var(--text-secondary);
    font-size: 0.85rem;
    letter-spacing: 0.5px;
}

/* Project Detail Pages */
.project-hero {
    padding: 150px 0 80px;
    background: linear-gradient(to bottom, var(--surface-color), var(--bg-color));
    border-bottom: 1px solid var(--glass-border);
}

.project-hero h1 {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    margin-bottom: 1.5rem;
}

.project-meta {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.project-content {
    display: grid;
    grid-template-columns: 1fr 350px;
    gap: 4rem;
    padding: 80px 0;
}

.project-main h2 {
    margin: 2.5rem 0 1rem;
    color: var(--accent-color);
}

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

.project-sidebar {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.sidebar-card {
    background: var(--surface-color);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--glass-border);
}

.sidebar-card h4 {
    margin-bottom: 1rem;
    color: var(--accent-color);
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 1px;
}

.project-image-large {
    width: 100%;
    border-radius: 16px;
    border: 1px solid var(--glass-border);
    margin: 2rem 0;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
    background: rgba(255, 255, 255, 0.05);
    /* Support for transparent PNG background */
    padding: 1.5rem;
}

.research-img {
    width: 100%;
    height: 200px;
    object-fit: contain;
    /* Changed from cover to support scientific diagrams better */
    border-radius: 12px;
    margin-bottom: 1rem;
    background: rgba(255, 255, 255, 0.04);
    /* Light background for transparent images */
    padding: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-color);
    font-weight: 600;
    margin-bottom: 2rem;
}

.back-link:hover {
    transform: translateX(-5px);
}

/* Contact Section */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.contact-card {
    background: var(--surface-color);
    padding: 2.5rem 2rem;
    border-radius: 24px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--glass-border);
    text-decoration: none;
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.2rem;
}

.contact-card:hover {
    transform: translateY(-8px);
    border-color: var(--accent-color);
    background: rgba(255, 255, 255, 0.04);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.contact-icon {
    width: 56px;
    height: 56px;
    filter: brightness(1.1);
}

.contact-card h4 {
    font-size: 1.2rem;
    color: var(--accent-color);
}

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

@media (max-width: 900px) {
    .project-content {
        grid-template-columns: 1fr;
    }

    .project-sidebar {
        order: -1;
    }
}

.card .btn-outline {
    margin-top: auto;
    align-self: flex-start;
}

/* Animations */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition);
}

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

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: var(--accent-color);
    color: #fff;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 14px 0 var(--accent-glow);
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
    transform: translateY(20px);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background-color: var(--accent-secondary);
    transform: translateY(-5px);
    box-shadow: 0 6px 20px 0 var(--accent-glow);
}

/* Floating Switcher */
.floating-switcher {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    padding: 6px;
    border-radius: 50px;
    display: flex;
    gap: 5px;
    z-index: 1000;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.floating-switcher.visible {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.switcher-btn {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.switcher-btn:hover {
    color: #fff;
    background: rgba(255, 255, 255, 0.1);
}

.switcher-btn.active {
    background: var(--accent-color);
    color: #fff;
    box-shadow: 0 2px 10px var(--accent-glow);
}

/* Project Tag in Publications */
.project-tag {
    display: inline-block;
    background: rgba(251, 146, 60, 0.1);
    color: var(--accent-color);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    margin-left: 10px;
    text-decoration: none;
    transition: var(--transition);
    border: 1px solid rgba(251, 146, 60, 0.2);
}

.project-tag:hover {
    background: var(--accent-color);
    color: white;
    transform: translateY(-1px);
}

.pub-authors {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 0.3rem 0;
    font-style: italic;
}