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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --dark-bg: #0f172a;
    --light-bg: #1e293b;
    --text-light: #f1f5f9;
    --text-gray: #cbd5e1;
    --gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-alt: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--dark-bg);
    color: var(--text-light);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Navigation */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    padding: 1rem 0;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    flex-wrap: wrap;
}

nav ul li {
    margin: 0 1.5rem;
}

nav ul li a {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    position: relative;
    padding: 0.5rem 0;
}

nav ul li a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-color);
    transition: width 0.3s ease;
}

nav ul li a:hover::after {
    width: 100%;
}

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

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    background: var(--gradient); /* fallback if video doesn't load */
}
/* Fullscreen background video */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    background: var(--gradient); /* fallback only */
}

/* Fullscreen background video */
.hero-video {
    position: absolute;
    top: 50%;
    left: 50%;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
    transform: translate(-50%, -50%);
    object-fit: cover;
    filter: blur(5px);          /* slight blur */
    transform-origin: center;
    z-index: 0;
}

.hero-content p {
    max-width: 750px;
    margin-left: auto;
    margin-right: auto;
}

.hero-content p {
    max-width: 750px;
    margin-left: auto;
    margin-right: auto;
}

.hero h1 {
    font-size: 4rem;
    margin-bottom: 1rem;
    text-shadow: 0 4px 18px rgba(0, 0, 0, 0.75);  /* stronger shadow */
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: rgba(15, 23, 42, 0.7);  /* was 0.55 – make it darker */
    z-index: 0;
}


.hero-content {
    position: relative;
    z-index: 1;
}


/*
.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="100" height="100" patternUnits="userSpaceOnUse"><path d="M 100 0 L 0 0 0 100" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="1"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grid)"/></svg>');
    animation: gridMove 20s linear infinite;
}
*/

@keyframes gridMove {
    0% { transform: translate(0, 0); }
    100% { transform: translate(100px, 100px); }
}

.hero-content {
    text-align: center;
    z-index: 1;
    padding: 2rem;
}

/* New: hero photo styles */
.hero-photo {
    width: 160px;
    height: 160px;
    margin: 0 auto 1.5rem auto;
    border-radius: 50%;
    overflow: hidden;
    border: 4px solid rgba(241, 245, 249, 0.9);
    box-shadow: 0 10px 25px rgba(15, 23, 42, 0.4);
}

.hero-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}


.hero h1 {
    font-size: 4rem;
    margin-bottom: 1rem;
    animation: fadeInUp 1s ease;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.hero .subtitle {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    animation: fadeInUp 1s ease 0.2s both;
    color: var(--text-light);
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    animation: fadeInUp 1s ease 0.4s both;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 1s ease 0.6s both;
}

.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background: white;
    color: var(--secondary-color);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: var(--secondary-color);
    transform: translateY(-3px);
}

/* Section Styles */
section {
    padding: 5rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

section h2 {
    font-size: 2.5rem;
    margin-bottom: 3rem;
    text-align: center;
    position: relative;
    color: var(--text-light);
}

section h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--gradient);
    border-radius: 2px;
}

/* About Section */
.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.about-text p {
    margin-bottom: 1rem;
    color: var(--text-gray);
    font-size: 1.1rem;
}

.stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin-top: 2rem;
}

.stat-card {
    background: var(--light-bg);
    padding: 1.5rem;
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.3);
}

.stat-card h3 {
    font-size: 2rem;
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.skill-category {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 15px;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.skill-category:hover {
    border-color: var(--accent-color);
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(59, 130, 246, 0.2);
}

.skill-category h3 {
    color: var(--accent-color);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.skill-category ul {
    list-style: none;
}

.skill-category li {
    padding: 0.5rem 0;
    color: var(--text-gray);
    position: relative;
    padding-left: 1.5rem;
}

.skill-category li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

/* Experience Section */
.experience-timeline {
    position: relative;
    padding-left: 2rem;
}

.experience-item {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 15px;
    margin-bottom: 2rem;
    position: relative;
    border-left: 4px solid var(--accent-color);
    transition: all 0.3s ease;
}

.experience-item:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 40px rgba(59, 130, 246, 0.3);
}

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

.experience-header h3 {
    color: var(--accent-color);
    font-size: 1.4rem;
}

.experience-header .company {
    font-size: 1.1rem;
    color: var(--text-light);
    font-weight: 600;
}

.experience-header .date {
    color: var(--text-gray);
    font-style: italic;
}

.experience-item ul {
    list-style: none;
    margin-top: 1rem;
}

.experience-item li {
    color: var(--text-gray);
    margin-bottom: 0.8rem;
    padding-left: 1.5rem;
    position: relative;
}

.experience-item li::before {
    content: '●';
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

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

.project-card {
    background: var(--light-bg);
    border-radius: 15px;
    overflow: hidden;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.project-card:hover {
    transform: translateY(-10px);
    border-color: var(--accent-color);
    box-shadow: 0 20px 40px rgba(59, 130, 246, 0.4);
}

.project-header {
    padding: 2rem;
    background: var(--gradient);
}

.project-header h3 {
    color: white;
    margin-bottom: 0.5rem;
}

.project-content {
    padding: 2rem;
}

.project-content p {
    color: var(--text-gray);
    margin-bottom: 1rem;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.tag {
    background: var(--accent-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
}

/* Publications Section */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.publication-item {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 15px;
    border-left: 4px solid var(--accent-color);
    transition: all 0.3s ease;
}

.publication-item:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 40px rgba(59, 130, 246, 0.3);
}

.publication-item h3 {
    color: var(--accent-color);
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.publication-meta {
    color: var(--text-gray);
    font-style: italic;
    margin-top: 0.5rem;
}

/* Education Section */
.education-grid {
    display: grid;
    gap: 2rem;
}

.education-card {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 15px;
    border-left: 4px solid var(--accent-color);
    transition: all 0.3s ease;
}

.education-card:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 40px rgba(59, 130, 246, 0.3);
}

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

.education-header h3 {
    color: var(--accent-color);
    font-size: 1.4rem;
}

.education-details {
    margin-top: 1rem;
}

.education-details p {
    color: var(--text-gray);
    margin-bottom: 0.5rem;
}

.honors {
    margin-top: 1rem;
    padding: 1rem;
    background: rgba(59, 130, 246, 0.1);
    border-radius: 10px;
}

.honors h4 {
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.honors ul {
    list-style: none;
}

.honors li {
    color: var(--text-gray);
    padding: 0.3rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.honors li::before {
    content: '🏆';
    position: absolute;
    left: 0;
}

/* Contact Section */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--text-gray);
    transition: all 0.3s ease;
}

.contact-item:hover {
    transform: translateX(10px);
    color: var(--accent-color);
}

.contact-item i {
    font-size: 1.5rem;
    color: var(--accent-color);
}

.social-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.social-link {
    width: 50px;
    height: 50px;
    background: var(--light-bg);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-color);
    font-size: 1.5rem;
    transition: all 0.3s ease;
    text-decoration: none;
}

.social-link:hover {
    background: var(--accent-color);
    color: white;
    transform: translateY(-5px);
}

/* Footer */
footer {
    background: var(--light-bg);
    text-align: center;
    padding: 2rem;
    color: var(--text-gray);
}

/* Animations */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .hero .subtitle {
        font-size: 1.2rem;
    }

    .about-content,
    .contact-content {
        grid-template-columns: 1fr;
    }

    .stats {
        grid-template-columns: 1fr;
    }

    nav ul {
        flex-direction: column;
        align-items: center;
    }

    nav ul li {
        margin: 0.5rem 0;
    }

    section {
        padding: 3rem 1rem;
    }
}

/* Scroll Progress Bar */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: var(--gradient);
    z-index: 9999;
    transition: width 0.1s ease;
}
/* Button Link Styles */
.btn-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
    margin-top: 1rem;
    transition: all 0.3s ease;
}

.btn-link:hover {
    gap: 1rem;
    color: var(--text-light);
}

.btn-link i {
    transition: transform 0.3s ease;
}

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

/* Detail Page Styles */
.detail-page {
    min-height: 100vh;
    padding-top: 80px;
}

.back-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
}

.back-button:hover {
    gap: 1rem;
    color: var(--text-light);
}

.back-button i {
    transition: transform 0.3s ease;
}

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

.detail-header {
    background: var(--gradient);
    padding: 3rem 2rem;
    border-radius: 15px;
    margin-bottom: 3rem;
}

.detail-header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.detail-meta {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
    margin-top: 1rem;
    color: var(--text-light);
}

.detail-meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.detail-content {
    background: var(--light-bg);
    padding: 3rem;
    border-radius: 15px;
    margin-bottom: 2rem;
}

.detail-content h2 {
    color: var(--accent-color);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-size: 1.8rem;
}

.detail-content h3 {
    color: var(--text-light);
    margin-top: 1.5rem;
    margin-bottom: 0.8rem;
    font-size: 1.4rem;
}

.detail-content p {
    color: var(--text-gray);
    margin-bottom: 1rem;
    line-height: 1.8;
}

.detail-content ul, .detail-content ol {
    color: var(--text-gray);
    margin-left: 2rem;
    margin-bottom: 1rem;
}

.detail-content li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.code-block {
    background: var(--dark-bg);
    padding: 1.5rem;
    border-radius: 10px;
    margin: 1.5rem 0;
    overflow-x: auto;
    border-left: 4px solid var(--accent-color);
}

.code-block code {
    color: #a5d6ff;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.highlight-box {
    background: rgba(59, 130, 246, 0.1);
    border-left: 4px solid var(--accent-color);
    padding: 1.5rem;
    margin: 1.5rem 0;
    border-radius: 5px;
}

.tech-stack {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 1.5rem 0;
}

.tech-badge {
    background: var(--accent-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.metric-card {
    background: var(--dark-bg);
    padding: 1.5rem;
    border-radius: 10px;
    text-align: center;
}

.metric-value {
    font-size: 2rem;
    color: var(--accent-color);
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.metric-label {
    color: var(--text-gray);
    font-size: 0.9rem;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    margin-top: 1.5rem;
}

.form-row {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.form-row label {
    font-weight: 600;
    color: var(--text-light);
}

.form-row input,
.form-row textarea {
    padding: 0.8rem 1rem;
    border-radius: 8px;
    border: 1px solid rgba(148, 163, 184, 0.7);
    background: #0b1220;
    color: var(--text-light);
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.form-row input:focus,
.form-row textarea:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 1px rgba(59, 130, 246, 0.7);
    background: #020617;
}

.form-row textarea {
    resize: vertical;
}
/* Hamburger Menu Button (Hidden on Desktop) */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    position: fixed;
    top: 1rem;
    right: 1.5rem;
    z-index: 1001;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-light);
    border-radius: 3px;
    transition: all 0.3s ease;
}

/* Hamburger animation when active */
.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(7px, 7px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* Mobile Navigation Styles */
@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    nav ul {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: rgba(15, 23, 42, 0.98);
        backdrop-filter: blur(10px);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        transition: right 0.3s ease;
        z-index: 999;
        padding-top: 60px;
    }
    
    nav ul.active {
        right: 0;
    }
    
    nav ul li {
        margin: 1.5rem 0;
        width: 80%;
        text-align: center;
    }
    
    nav ul li a {
        display: block;
        padding: 1rem;
        font-size: 1.2rem;
    }
    
    /* Overlay to close menu when clicking outside */
    body::after {
        content: '';
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(0, 0, 0, 0.5);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
        z-index: 998;
    }
    
    body.menu-open::after {
        opacity: 1;
        visibility: visible;
    }
    
    body.menu-open {
        overflow: hidden;
    }
}