/* ========================================
   CSS Variables & Reset
======================================== */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #ec4899;
    --accent: #06b6d4;
    --dark: #0f172a;
    --dark-light: #1e293b;
    --gray: #64748b;
    --gray-light: #94a3b8;
    --light: #f1f5f9;
    --white: #ffffff;
    --gradient: linear-gradient(135deg, var(--primary), var(--secondary));
    --shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 25px 50px rgba(0, 0, 0, 0.15);
    --radius: 16px;
    --radius-sm: 8px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Prompt', sans-serif;
    background: var(--dark);
    color: var(--white);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ========================================
   Navbar
======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 1rem 2rem;
    transition: var(--transition);
    background: transparent;
}

.navbar.scrolled {
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow);
}

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white);
    text-decoration: none;
}

.nav-logo i {
    color: var(--primary-light);
}

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

.nav-link {
    color: var(--gray-light);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient);
    transition: var(--transition);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background: var(--white);
    transition: var(--transition);
}

/* ========================================
   Hero Section
======================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: linear-gradient(135deg, var(--dark) 0%, var(--dark-light) 100%);
    overflow: hidden;
    padding: 6rem 2rem 2rem;
}

.hero::before {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.3), transparent 70%);
    top: -200px;
    right: -200px;
    animation: pulse 8s ease-in-out infinite;
}

.hero::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(236, 72, 153, 0.2), transparent 70%);
    bottom: -100px;
    left: -100px;
    animation: pulse 6s ease-in-out infinite reverse;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
        opacity: 0.5;
    }

    50% {
        transform: scale(1.1);
        opacity: 0.8;
    }
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 4rem;
    max-width: 1200px;
    z-index: 10;
    flex-wrap: wrap;
    justify-content: center;
}

.hero-image {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    background: var(--gradient);
    padding: 5px;
    box-shadow: 0 0 60px rgba(99, 102, 241, 0.4);
    animation: float 6s ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-20px);
    }
}

.profile-img {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    display: block;
}

.hero-text {
    text-align: left;
}

.hero-subtitle {
    color: var(--primary-light);
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    letter-spacing: 2px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.gradient-text {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-position,
.hero-department {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--gray-light);
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.hero-position i,
.hero-department i {
    color: var(--primary-light);
}

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

/* ========================================
   Buttons
======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: var(--gradient);
    color: var(--white);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(99, 102, 241, 0.5);
}

.btn-outline {
    background: transparent;
    color: var(--white);
    border: 2px solid var(--gray);
}

.btn-outline:hover {
    border-color: var(--primary-light);
    color: var(--primary-light);
}

/* ========================================
   Sections
======================================== */
.section {
    padding: 6rem 2rem;
    position: relative;
}

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

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

.section-tag {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-light);
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.section-divider {
    width: 80px;
    height: 4px;
    background: var(--gradient);
    margin: 0 auto;
    border-radius: 2px;
}

/* ========================================
   About Section
======================================== */
.about {
    background: var(--dark-light);
}

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

.about-intro {
    font-size: 1.1rem;
    color: var(--gray-light);
    margin-bottom: 2rem;
    line-height: 1.8;
}

.about-details {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.detail-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-sm);
}

.detail-item i {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    border-radius: 50%;
    color: var(--white);
}

.detail-label {
    display: block;
    font-size: 0.8rem;
    color: var(--gray);
}

.detail-value {
    font-weight: 600;
}

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

.stat-card {
    background: rgba(255, 255, 255, 0.05);
    padding: 2rem;
    border-radius: var(--radius);
    text-align: center;
    transition: var(--transition);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.stat-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-light);
}

.stat-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    border-radius: 50%;
    font-size: 1.5rem;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--white);
}

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

/* ========================================
   Timeline (Education)
======================================== */
.education {
    background: var(--dark);
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;
    background: var(--gradient);
}

.timeline-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 3rem;
    position: relative;
}

.timeline-item:nth-child(odd) {
    flex-direction: row-reverse;
    text-align: right;
}

.timeline-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 50px;
    background: var(--gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    z-index: 10;
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.5);
}

.timeline-content {
    width: 45%;
    padding: 1.5rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.timeline-date {
    color: var(--primary-light);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.timeline-content h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.timeline-content p {
    color: var(--gray-light);
    margin-bottom: 0.25rem;
}

.timeline-institution {
    font-style: italic;
}

.timeline-institution i {
    margin-right: 0.5rem;
}

/* ========================================
   Skills Section
======================================== */
.skills {
    background: var(--dark-light);
}

.skills-container {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.skills-category h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.3rem;
    margin-bottom: 1.5rem;
    color: var(--primary-light);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.skill-item {
    background: rgba(255, 255, 255, 0.05);
    padding: 1.5rem;
    border-radius: var(--radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition);
}

.skill-item:hover {
    border-color: var(--primary-light);
    transform: translateY(-3px);
}

.skill-item i {
    font-size: 2rem;
    color: var(--primary-light);
    margin-bottom: 0.5rem;
}

.skill-item span {
    display: block;
    font-weight: 600;
    margin-bottom: 1rem;
}

.skill-bar {
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    background: var(--gradient);
    border-radius: 4px;
    width: 0;
    transition: width 1s ease;
}

/* ========================================
   Research Section
======================================== */
.research {
    background: var(--dark);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.research-card {
    background: rgba(255, 255, 255, 0.05);
    padding: 2rem;
    border-radius: var(--radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.research-card:hover {
    border-color: var(--primary-light);
    transform: translateY(-5px);
}

.research-year {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--gradient);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.research-card h3 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    padding-right: 60px;
}

.research-card p {
    color: var(--gray-light);
    font-size: 0.9rem;
}

.research-card i {
    color: var(--primary-light);
    margin-right: 0.5rem;
}

.research-link {
    color: var(--white);
    text-decoration: none;
    transition: var(--transition);
    display: inline-block;
}

.research-link:visited {
    color: var(--white);
}

.research-link:hover,
.research-link:active,
.research-link:focus {
    color: var(--primary-light);
    outline: none;
}

.research-link i {
    font-size: 0.8em;
    margin-left: 0.5rem;
    opacity: 0.7;
}

.research-citation {
    font-size: 0.9rem;
    color: var(--gray-light);
    line-height: 1.6;
}

.research-citation em {
    font-style: italic;
    color: var(--gray-light);
    /* Keep consistent or make slightly lighter */
}

/* ========================================
   Contact Section
======================================== */
.contact {
    background: var(--dark-light);
}

.contact-grid {
    display: flex;
    justify-content: center;
    gap: 4rem;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.contact-icon {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    border-radius: 50%;
    flex-shrink: 0;
}

.contact-label {
    display: block;
    font-size: 0.85rem;
    color: var(--gray);
    margin-bottom: 0.25rem;
}

.contact-item a,
.contact-item span {
    color: var(--white);
    text-decoration: none;
}

.contact-item a:hover {
    color: var(--primary-light);
}

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

.social-link {
    width: 45px;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 50%;
    color: var(--white);
    text-decoration: none;
    transition: var(--transition);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.social-link:hover {
    background: var(--gradient);
    transform: translateY(-3px);
}


/* ========================================
   Footer
======================================== */
.footer {
    background: var(--dark);
    padding: 2rem;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer p {
    color: var(--gray);
    font-size: 0.9rem;
}

/* ========================================
   Back to Top
======================================== */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: var(--gradient);
    border: none;
    border-radius: 50%;
    color: var(--white);
    font-size: 1.2rem;
    cursor: pointer;
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    z-index: 100;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
}

/* ========================================
   Responsive
======================================== */
@media (max-width: 992px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .timeline::before {
        left: 20px;
    }

    .timeline-marker {
        left: 20px;
        width: 40px;
        height: 40px;
    }

    .timeline-item,
    .timeline-item:nth-child(odd) {
        flex-direction: row;
        text-align: left;
        padding-left: 60px;
    }

    .timeline-content {
        width: 100%;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: var(--dark);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        transition: var(--transition);
    }

    .nav-menu.active {
        right: 0;
    }

    .nav-toggle {
        display: flex;
        z-index: 1001;
    }

    .hero-content {
        flex-direction: column;
        text-align: center;
    }

    .hero-text {
        text-align: center;
    }

    .hero-position,
    .hero-department {
        justify-content: center;
    }

    .hero-buttons {
        justify-content: center;
    }

    .hero-title {
        font-size: 2rem;
    }

    .section-title {
        font-size: 1.8rem;
    }

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