:root {
    --bg-main: #f8fafc; /* Slate 50 - Sleek light gray */
    --bg-secondary: #ffffff; /* White - clean surfaces */
    --bg-tertiary: #f1f5f9; /* Slate 100 - soft backgrounds */
    --text-primary: #0f172a; /* Slate 900 - dark charcoal for high contrast headers */
    --text-secondary: #475569; /* Slate 600 - elegant body text */
    --accent: #2563eb; /* Primary professional blue */
    --accent-hover: #1d4ed8; /* Darker blue on hover */
    --accent-light: rgba(37, 99, 235, 0.06); /* Soft blue wash */
    --accent-glow: rgba(37, 99, 235, 0.12); /* Subtle blue glow */
    --accent-secondary: #0d9488; /* Professional cybersecurity teal */
    --accent-secondary-light: rgba(13, 148, 136, 0.06); /* Soft teal wash */
    --font-main: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

html {
    scroll-behavior: smooth;
}

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

h1, h2, h3, h4, .text-primary {
    color: var(--text-primary);
}

a {
    text-decoration: none;
    color: var(--accent);
    transition: all 0.3s ease;
}

/* Cyber Grid Background */
.cyber-grid {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-image: 
        linear-gradient(rgba(37, 99, 235, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(37, 99, 235, 0.04) 1px, transparent 1px);
    background-size: 40px 40px;
    z-index: -1;
    opacity: 0.8;
}

/* Navigation */
.top-nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 100;
    border-bottom: 1px solid rgba(15, 23, 42, 0.04);
    box-shadow: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.top-nav.scrolled {
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 4px 20px rgba(15, 23, 42, 0.04);
    border-bottom-color: rgba(15, 23, 42, 0.06);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 1.25rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

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

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

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

/* Buttons */
.btn-primary, .btn-secondary, .btn-outline {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-family: var(--font-mono);
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.btn-primary {
    background-color: var(--accent);
    color: #ffffff !important;
    border: 1px solid var(--accent);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.15);
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    border-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.25);
}

.btn-secondary {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid rgba(15, 23, 42, 0.06);
}

.btn-secondary:hover {
    background-color: var(--bg-secondary);
    border-color: rgba(15, 23, 42, 0.15);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
}

.btn-outline {
    border: 1px solid var(--accent);
    color: var(--accent) !important;
    background-color: transparent;
}

.btn-outline:hover {
    background-color: var(--accent-light);
    transform: translateY(-2px);
}

/* Layout */
.section-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 100px 2rem;
}

.section-title {
    font-size: 2rem;
    display: flex;
    align-items: center;
    margin-bottom: 2.5rem;
    white-space: nowrap;
}

.section-title::after {
    content: "";
    display: block;
    height: 1px;
    width: 300px;
    background-color: var(--bg-tertiary);
    margin-left: 20px;
}

.highlight {
    color: var(--accent);
    font-family: var(--font-mono);
    font-size: 1.2rem;
    margin-right: 10px;
    font-weight: 400;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 0 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.terminal-prompt {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    margin-bottom: 24px;
    background-color: var(--bg-tertiary);
    border: 1px solid rgba(15, 23, 42, 0.08);
    padding: 10px 16px;
    border-radius: 8px;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    box-shadow: inset 0 1px 2px rgba(15, 23, 42, 0.02);
}

.terminal-prompt .user { color: var(--accent-secondary); font-weight: 600; }
.terminal-prompt .colon { color: #64748b; }
.terminal-prompt .dir { color: var(--accent); font-weight: 600; }
.terminal-prompt .prompt { color: #475569; margin-right: 6px; }
.terminal-prompt .typing-text {
    color: var(--text-primary);
    border-right: 2px solid var(--accent);
    padding-right: 5px;
    animation: blink 1s step-end infinite;
}

@keyframes blink {
    50% { border-color: transparent; }
}

.hero h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    margin: 0;
    font-weight: 800;
    line-height: 1.1;
}

.hero .subtitle {
    font-size: clamp(1.2rem, 3vw, 1.8rem);
    margin-top: 10px;
    color: var(--text-secondary);
    margin-bottom: 30px;
    max-width: 600px;
}

.hero .cta-buttons {
    display: flex;
    gap: 1.5rem;
}

/* About Section */
.about-section .text-content p {
    margin-bottom: 15px;
    font-size: 1.1rem;
    max-width: 700px;
}

.expertise-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 30px;
}

.tag {
    background-color: var(--accent-light);
    color: var(--accent);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    padding: 6px 14px;
    border-radius: 20px;
    border: 1px solid rgba(37, 99, 235, 0.12);
    font-weight: 500;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.tag:hover {
    background-color: var(--accent);
    color: #ffffff;
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.15);
}

/* Publications */
.publication-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.pub-card {
    display: flex;
    background-color: var(--bg-secondary);
    padding: 25px;
    border-radius: 12px;
    border: 1px solid rgba(15, 23, 42, 0.06);
    box-shadow: 0 4px 6px -1px rgba(15, 23, 42, 0.02), 0 2px 4px -2px rgba(15, 23, 42, 0.02);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), 
                box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1), 
                border-color 0.3s cubic-bezier(0.16, 1, 0.3, 1),
                background-color 0.3s ease;
    position: relative;
    overflow: hidden;
}

.pub-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background-color: var(--accent-secondary);
    transform: scaleY(0);
    transform-origin: bottom;
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.pub-card:hover {
    transform: translateY(-2px) translateX(4px);
    box-shadow: 0 12px 20px -8px rgba(15, 23, 42, 0.08), 0 4px 6px -2px rgba(15, 23, 42, 0.04);
    border-color: rgba(13, 148, 136, 0.25);
}

.pub-card:hover::before {
    transform: scaleY(1);
}

.pub-year {
    font-family: var(--font-mono);
    color: var(--accent-secondary);
    font-weight: 700;
    font-size: 1.1rem;
    min-width: 80px;
    padding-top: 2px;
}

.pub-details {
    flex-grow: 1;
}

.pub-title {
    font-size: 1.2rem;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.pub-authors {
    font-size: 0.95rem;
    margin-bottom: 5px;
    color: var(--text-secondary);
}

.pub-authors strong {
    color: var(--text-primary);
    font-weight: 600;
}

.pub-venue {
    font-style: italic;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
    opacity: 0.85;
}

.pub-links {
    display: flex;
    gap: 15px;
}

.pub-link {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent);
}

.pub-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

/* Projects */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
}

.project-card {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid rgba(15, 23, 42, 0.06);
    box-shadow: 0 4px 6px -1px rgba(15, 23, 42, 0.02), 0 2px 4px -2px rgba(15, 23, 42, 0.02);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), 
                box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1), 
                border-color 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.project-card:hover {
    transform: translateY(-6px);
    border-color: rgba(37, 99, 235, 0.2);
    box-shadow: 0 20px 25px -5px rgba(15, 23, 42, 0.06), 0 8px 10px -6px rgba(15, 23, 42, 0.06);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.folder-icon {
    color: var(--accent);
}

.project-links a {
    color: var(--text-secondary);
    transition: color 0.2s ease;
}

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

.project-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.project-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
    flex-grow: 1;
    line-height: 1.5;
}

.tech-stack {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.tech-stack span {
    background-color: var(--bg-tertiary);
    padding: 3px 8px;
    border-radius: 4px;
    border: 1px solid rgba(15, 23, 42, 0.04);
}

/* Contact */
.contact-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-content p {
    font-size: 1.1rem;
    margin-bottom: 40px;
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem 2rem;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    background-color: var(--bg-tertiary);
    border-top: 1px solid rgba(15, 23, 42, 0.05);
    color: var(--text-secondary);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 15px;
}

.footer-links a {
    color: var(--text-secondary);
    font-weight: 500;
}

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

/* Animations */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 1s ease-out forwards;
    animation-delay: 0.2s;
}

.slide-up {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

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

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

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .section-title::after {
        width: 100%;
    }
    
    .pub-card {
        flex-direction: column;
    }
    
    .pub-year {
        margin-bottom: 10px;
    }
    
    .hero .cta-buttons {
        flex-direction: column;
    }
}