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

:root {
    --primary-color: #000000;
    --secondary-color: #1a1a1a;
    --text-color: #ffffff;
    --light-text: #b0b0b0;
    --bg-color: #0a0a0a;
    --border-color: #2a2a2a;
    --hover-color: #1a1a1a;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    background-color: #0a0a0a;
    box-shadow: 0 2px 4px rgba(255, 255, 255, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

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

.nav-menu a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s ease;
    font-weight: 500;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 100px 0;
    text-align: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    font-weight: bold;
}

.hero-content .subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.95;
}

.hero-content .bio-intro {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: #f3f4f6;
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

/* Sections */
section {
    padding: 80px 0;
}

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

/* About Section */
.about {
    background-color: #1a1a1a;
}

.about p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--light-text);
    margin-bottom: 1.5rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.social-links {
    display: flex;
    gap: 2rem;
    justify-content: center;
    margin-top: 2rem;
}

.social-icon {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    padding: 8px 16px;
    border: 2px solid var(--primary-color);
    border-radius: 5px;
}

.social-icon:hover {
    background-color: var(--primary-color);
    color: white;
}

/* Experience Section */
.experience {
    background-color: #0a0a0a;
}

.timeline {
    position: relative;
    padding: 20px 0;
}

.timeline-item {
    display: flex;
    gap: 2rem;
    margin-bottom: 3rem;
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

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

.timeline-date {
    flex: 0 0 120px;
    font-weight: bold;
    color: var(--primary-color);
    font-size: 0.95rem;
}

.timeline-content {
    flex: 1;
    padding: 20px;
    background-color: #1a1a1a;
    border-left: 3px solid var(--primary-color);
    border-radius: 5px;
}

.timeline-content h3 {
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

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

.timeline-content p {
    color: var(--light-text);
    line-height: 1.6;
}

/* Skills Section */
.skills {
    background-color: #1a1a1a;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 3rem;
}

.skill-category {
    background-color: #0a0a0a;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
}

.skill-category h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.3rem;
}

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

.skill-category li {
    padding: 0.5rem 0;
    color: var(--text-color);
    border-bottom: 1px solid var(--border-color);
    padding-left: 1rem;
    position: relative;
}

.skill-category li:last-child {
    border-bottom: none;
}

.skill-category li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Projects Section */
.projects {
    background-color: #0a0a0a;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.project-card {
    background-color: #1a1a1a;
    border-radius: 8px;
    padding: 2rem;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.project-header {
    margin-bottom: 1rem;
}

.project-header h3 {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.project-card p {
    color: var(--light-text);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.tag {
    background-color: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
}

.project-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.project-link:hover {
    color: var(--secondary-color);
    margin-left: 5px;
}

/* Publications Section */
.publications {
    background-color: #1a1a1a;
}

.publications-list {
    max-width: 800px;
    margin: 0 auto;
}

.publication-item {
    background-color: #0a0a0a;
    padding: 2rem;
    margin-bottom: 2rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
}

.publication-item h3 {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.publication-meta {
    color: var(--light-text);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    font-style: italic;
}

.publication-item p {
    color: var(--light-text);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.read-more {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.read-more:hover {
    color: var(--secondary-color);
}

/* Contact Section */
.contact {
    background-color: #0a0a0a;
}

.contact-intro {
    font-size: 1.1rem;
    color: var(--light-text);
    text-align: center;
    margin-bottom: 3rem;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    max-width: 1000px;
    margin: 0 auto;
}

.contact-info h3 {
    color: var(--text-color);
    margin-bottom: 1.5rem;
}

.contact-item {
    margin-bottom: 1.5rem;
    color: var(--light-text);
}

.contact-item strong {
    color: var(--text-color);
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

/* Contact Form */
.contact-form {
    background-color: #1a1a1a;
    padding: 2rem;
    border-radius: 8px;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-color);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.3s ease;
    background-color: #0a0a0a;
    color: white;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.1);
}

.form-group textarea {
    resize: vertical;
}

/* Footer */
.footer {
    background-color: #000000;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s ease;
}

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

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

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

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

    section {
        padding: 50px 0;
    }

    section h2 {
        font-size: 2rem;
    }

    .timeline-item {
        flex-direction: column;
    }

    .timeline-date {
        flex: auto;
    }

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

    .footer .container {
        flex-direction: column;
        gap: 1rem;
    }

    .footer-links {
        gap: 1rem;
    }

    .social-links {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .navbar .container {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-menu {
        flex-direction: column;
        gap: 0.5rem;
        width: 100%;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .hero {
        padding: 50px 0;
    }

    section h2 {
        font-size: 1.5rem;
    }

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

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