@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Poppins:wght@300;400;500;600;700;800&display=swap');

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

:root {
    --primary-color: #0f172a;
    --secondary-color: #3b82f6;
    --accent-color: #8b5cf6;
    --accent-2: #ec4899;
    --text-color: #1e293b;
    --text-light: #64748b;
    --light-bg: #f8fafc;
    --white: #ffffff;
    --border-color: #e2e8f0;
    --gradient-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-2: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
    --gradient-3: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--white);
    overflow-x: hidden;
}

/* Background decorative elements */
.bg-decoration {
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.bg-decoration::before {
    content: '';
    position: absolute;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, transparent 70%);
    top: -400px;
    right: -400px;
    border-radius: 50%;
}

.bg-decoration::after {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.1) 0%, transparent 70%);
    bottom: -300px;
    left: -300px;
    border-radius: 50%;
}

/* Navigation */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.05);
    border-bottom: 1px solid rgba(226, 232, 240, 0.5);
    z-index: 1000;
    transition: all 0.3s ease;
}

nav.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}

nav .container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.2rem 2rem;
}

nav .logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-family: 'Poppins', sans-serif;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

nav a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.3s;
    position: relative;
}

nav a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-2);
    transition: width 0.3s ease;
}

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

nav a:hover {
    color: var(--secondary-color);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    position: relative;
    color: var(--white);
    padding: 120px 2rem 4rem;
    text-align: center;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    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(255,255,255,0.03)" stroke-width="1"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 900px;
}

.hero-content h1 {
    font-size: 4.5rem;
    margin-bottom: 1.5rem;
    font-weight: 800;
    font-family: 'Poppins', sans-serif;
    letter-spacing: -2px;
    animation: fadeInUp 0.8s ease-out;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.hero-content .subtitle {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    opacity: 0.95;
    font-weight: 600;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-content .tagline {
    font-size: 1.3rem;
    margin-bottom: 3rem;
    opacity: 0.9;
    font-weight: 400;
    line-height: 1.8;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.social-links {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

.social-links a {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border-radius: 50%;
    color: var(--white);
    font-size: 1.3rem;
    transition: all 0.3s ease;
    text-decoration: none;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.social-links a:hover {
    transform: translateY(-5px) scale(1.1);
    background: rgba(255, 255, 255, 0.25);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

/* Floating animation for hero decorations */
@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

.hero::after {
    content: '';
    position: absolute;
    width: 300px;
    height: 300px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 50%;
    bottom: -150px;
    right: -150px;
    animation: float 6s ease-in-out infinite;
}

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

/* Sections */
section {
    padding: 6rem 0;
    position: relative;
}

section h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
    text-align: center;
    color: var(--primary-color);
    font-weight: 800;
    font-family: 'Poppins', sans-serif;
    position: relative;
    display: inline-block;
    left: 50%;
    transform: translateX(-50%);
}

section h2::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--gradient-2);
    border-radius: 2px;
}

section > .container > h2 + * {
    margin-top: 4rem;
}

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

.about-text p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    text-align: justify;
}

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

.stat-card {
    background: var(--white);
    padding: 2.5rem;
    border-radius: 20px;
    text-align: center;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-2);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.stat-card:hover::before {
    transform: scaleX(1);
}

.stat-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px rgba(59, 130, 246, 0.15);
    border-color: var(--secondary-color);
}

.stat-card h3 {
    font-size: 3.5rem;
    background: var(--gradient-2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
    font-weight: 800;
}

.stat-card p {
    color: var(--text-light);
    font-weight: 600;
    font-size: 1.05rem;
}

/* Research Areas */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.research-card {
    background: var(--white);
    padding: 2.5rem;
    border: 2px solid var(--border-color);
    border-radius: 20px;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
}

.research-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: var(--gradient-2);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

.research-card:hover::before {
    transform: scaleX(1);
}

.research-card:hover {
    border-color: var(--secondary-color);
    box-shadow: 0 20px 60px rgba(59, 130, 246, 0.15);
    transform: translateY(-10px);
}

.research-card h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.4rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.research-card ul {
    list-style: none;
    padding-left: 0;
}

.research-card ul li {
    padding: 0.7rem 0;
    padding-left: 1.8rem;
    position: relative;
    color: var(--text-light);
    font-size: 0.95rem;
    transition: all 0.3s;
}

.research-card ul li:before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: 700;
    transition: transform 0.3s;
}

.research-card ul li:hover {
    color: var(--text-color);
    padding-left: 2rem;
}

.research-card ul li:hover:before {
    transform: translateX(3px);
}

/* Publications */
.publications-list {
    max-width: 900px;
    margin: 0 auto;
}

.publication-item {
    background: var(--white);
    padding: 2rem;
    margin-bottom: 2rem;
    border-radius: 16px;
    border: 2px solid var(--border-color);
    border-left: 5px solid var(--secondary-color);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
}

.publication-item:hover {
    background: var(--white);
    box-shadow: 0 15px 50px rgba(59, 130, 246, 0.12);
    transform: translateX(10px);
    border-left-color: var(--accent-color);
}

.publication-item h4 {
    color: var(--primary-color);
    margin-bottom: 0.8rem;
    font-size: 1.15rem;
    line-height: 1.6;
    font-weight: 600;
}

.publication-item p {
    color: var(--text-light);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Contact Section */
.contact-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.contact-card {
    background: var(--white);
    padding: 2.5rem;
    border-radius: 20px;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    border: 2px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.contact-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-2);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.contact-card:hover::before {
    transform: scaleX(1);
}

.contact-card:hover {
    background: var(--white);
    box-shadow: 0 20px 60px rgba(59, 130, 246, 0.15);
    transform: translateY(-10px);
    border-color: var(--secondary-color);
}

.contact-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-weight: 700;
    font-size: 1.3rem;
}

.contact-card a {
    color: var(--secondary-color);
    text-decoration: none;
    word-break: break-all;
    transition: color 0.3s;
    font-weight: 500;
}

.contact-card a:hover {
    color: var(--accent-color);
}

.contact-card p {
    color: var(--text-light);
    line-height: 1.8;
}

/* Chatbot */
.chatbot-container {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    z-index: 1000;
}

.chatbot-button {
    width: 65px;
    height: 65px;
    border-radius: 50%;
    background: var(--gradient-2);
    color: var(--white);
    border: none;
    font-size: 1.6rem;
    cursor: pointer;
    box-shadow: 0 8px 30px rgba(59, 130, 246, 0.4);
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    display: flex;
    align-items: center;
    justify-content: center;
}

.chatbot-button:hover {
    transform: scale(1.15) rotate(10deg);
    box-shadow: 0 12px 40px rgba(59, 130, 246, 0.5);
}

.chatbot-window {
    display: none;
    position: fixed;
    bottom: 110px;
    right: 2rem;
    width: 400px;
    height: 550px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 24px;
    box-shadow: 0 20px 70px rgba(0, 0, 0, 0.15);
    flex-direction: column;
    overflow: hidden;
    border: 1px solid rgba(226, 232, 240, 0.5);
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.chatbot-window.active {
    display: flex;
}

.chatbot-header {
    background: var(--gradient-2);
    color: var(--white);
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.chatbot-header h3 {
    font-size: 1.2rem;
    margin: 0;
    font-weight: 600;
}

.close-chat {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: var(--white);
    font-size: 1.5rem;
    cursor: pointer;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
}

.close-chat:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: rotate(90deg);
}

.chatbot-messages {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
    background: #f8fafc;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.chatbot-messages::-webkit-scrollbar {
    width: 6px;
}

.chatbot-messages::-webkit-scrollbar-track {
    background: transparent;
}

.chatbot-messages::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 3px;
}

.message {
    padding: 1rem 1.2rem;
    border-radius: 16px;
    max-width: 80%;
    word-wrap: break-word;
    animation: messageSlide 0.3s ease-out;
    line-height: 1.6;
}

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

.message.bot {
    background: var(--white);
    align-self: flex-start;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.message.user {
    background: var(--gradient-2);
    color: var(--white);
    margin-left: auto;
    align-self: flex-end;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.chatbot-input-area {
    display: flex;
    padding: 1.2rem;
    background: var(--white);
    border-top: 1px solid var(--border-color);
    gap: 0.8rem;
}

.chatbot-input-area input {
    flex: 1;
    padding: 0.9rem 1.2rem;
    border: 2px solid var(--border-color);
    border-radius: 24px;
    outline: none;
    font-size: 0.95rem;
    transition: all 0.3s;
    font-family: 'Inter', sans-serif;
}

.chatbot-input-area input:focus {
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.chatbot-input-area button {
    background: var(--gradient-2);
    color: var(--white);
    border: none;
    padding: 0.9rem 1.8rem;
    border-radius: 24px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.chatbot-input-area button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.4);
}

.chatbot-input-area button:active {
    transform: translateY(0);
}

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

/* Skills badges */
.skills-container {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    margin-top: 3rem;
}

.skill-badge {
    background: var(--white);
    color: var(--primary-color);
    padding: 0.7rem 1.5rem;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 600;
    border: 2px solid var(--border-color);
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    cursor: default;
}

.skill-badge:hover {
    background: var(--gradient-2);
    color: var(--white);
    border-color: transparent;
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(59, 130, 246, 0.3);
}

/* Responsive */
@media (max-width: 768px) {
    nav ul {
        gap: 1rem;
        font-size: 0.9rem;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

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

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

    .chatbot-window {
        width: calc(100% - 2rem);
        right: 1rem;
    }

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

    section h2 {
        font-size: 2rem;
    }
}