:root {
    --bg-color: #050505;
    --surface-color: rgba(255, 255, 255, 0.03);
    --surface-hover: rgba(255, 255, 255, 0.08);
    --border-color: rgba(255, 255, 255, 0.08);
    --primary: #38BDF8;
    --secondary: #818CF8;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

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

/* Glassmorphism utility */
.glass-panel {
    background: var(--surface-color);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    transition: var(--transition);
}

.glass-panel:hover {
    background: var(--surface-hover);
    border-color: rgba(255, 255, 255, 0.15);
    transform: translateY(-5px);
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(5, 5, 5, 0.7);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}

.nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-main);
    text-decoration: none;
}

.logo span {
    color: var(--primary);
}

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

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

.nav-links a:hover, .nav-links a.active {
    color: var(--primary);
}

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

/* Layout */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section-padding {
    padding: 100px 0;
}

.section-title {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    text-align: left;
    background: linear-gradient(to right, var(--text-main), var(--text-muted));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Hero Section */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 120px;
}

.hero-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    gap: 4rem;
}

.hero-text {
    flex: 1;
}

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

.name {
    font-family: var(--font-heading);
    font-size: 4.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1rem;
}

.title {
    font-family: var(--font-heading);
    font-size: 2rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

.tagline {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 500px;
}

.contact-info {
    display: flex;
    gap: 1rem;
}

.contact-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    background: var(--surface-color);
    color: var(--text-main);
    border: 1px solid var(--border-color);
}

.contact-btn:hover {
    background: var(--surface-hover);
    transform: translateY(-2px);
}

.contact-btn.linkedin {
    background: linear-gradient(135deg, #0077b5, #005e93);
    border: none;
}

.contact-btn.linkedin:hover {
    box-shadow: 0 10px 20px rgba(0, 119, 181, 0.3);
}

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

.image-wrapper {
    position: relative;
    width: 350px;
    height: 350px;
}

.image-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    z-index: 2;
    position: relative;
    border: 2px solid rgba(255, 255, 255, 0.1);
}

.glow-effect {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    background: radial-gradient(circle, var(--primary) 0%, transparent 70%);
    opacity: 0.2;
    filter: blur(50px);
    z-index: 1;
    animation: pulse 4s infinite alternate;
}

@keyframes pulse {
    0% { transform: translate(-50%, -50%) scale(1); opacity: 0.15; }
    100% { transform: translate(-50%, -50%) scale(1.1); opacity: 0.3; }
}

/* About */
.about-card p {
    margin-bottom: 1rem;
    font-size: 1.05rem;
    color: var(--text-muted);
}
.about-card p:last-child {
    margin-bottom: 0;
}

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

.skill-category h3 {
    font-family: var(--font-heading);
    margin-bottom: 1.5rem;
    color: var(--primary);
    font-size: 1.2rem;
}

.chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.chip {
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--text-main);
    transition: var(--transition);
    cursor: default;
}

.chip:hover {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-color: transparent;
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(56, 189, 248, 0.3);
}

/* Experience Timeline */
.timeline {
    position: relative;
    padding-left: 3rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--primary), var(--secondary), transparent);
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: -3.35rem;
    top: 1.5rem;
    width: 16px;
    height: 16px;
    background: var(--bg-color);
    border: 2px solid var(--primary);
    border-radius: 50%;
    z-index: 2;
    transition: var(--transition);
}

.timeline-item:hover .timeline-dot {
    background: var(--primary);
    box-shadow: 0 0 15px var(--primary);
}

.timeline-content h3 {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    color: var(--text-main);
    margin-bottom: 0.3rem;
}

.timeline-content h4 {
    font-weight: 500;
    color: var(--primary);
    font-size: 1rem;
    margin-bottom: 1rem;
}

.timeline-content .date {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    background: rgba(255,255,255,0.05);
    border-radius: 4px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Education */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.edu-card h3 {
    font-family: var(--font-heading);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.edu-card .institution {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.edu-card .meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
    font-size: 0.9rem;
}

.edu-card .grade {
    color: var(--primary);
    font-weight: 600;
}

/* Research */
.research-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

.tab-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-heading);
    font-size: 1.1rem;
    cursor: pointer;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: var(--transition);
}

.tab-btn:hover {
    color: var(--text-main);
    background: rgba(255,255,255,0.05);
}

.tab-btn.active {
    color: var(--text-main);
    background: var(--surface-hover);
    box-shadow: inset 0 -2px 0 var(--primary);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.research-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.research-list li {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.research-list li i {
    font-size: 1.5rem;
    color: var(--secondary);
    margin-top: 0.2rem;
}

.research-list li p {
    color: var(--text-main);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.research-list li .status {
    font-size: 0.85rem;
    color: var(--primary);
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem 0;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
}

/* Animations (Scroll reveal) */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

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

.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }

/* Footer Contact */
.footer-contact {
    margin-top: 1rem;
}
.footer-contact a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}
.footer-contact a:hover {
    color: var(--secondary);
}

/* Go To Top Button */
#go-top-btn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(56, 189, 248, 0.4);
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
}

#go-top-btn.show {
    opacity: 1;
    visibility: visible;
}

#go-top-btn:hover {
    background: var(--secondary);
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(129, 140, 248, 0.5);
}

/* Responsive */
@media (max-width: 900px) {
    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
        margin-top: -50px;
    }
    .hero-text {
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    .name { font-size: 3rem; }
    .title { font-size: 1.5rem; }
    .image-wrapper {
        width: 280px;
        height: 280px;
    }
    .contact-info {
        flex-direction: column;
        width: 100%;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    .mobile-menu-btn {
        display: block;
    }
    .grid-2 {
        grid-template-columns: 1fr;
    }
}