/* ==================== */
/* CSS Variables */
/* ==================== */
:root {
    --primary-color: #333;
    --secondary-color: #666;
    --accent-color: #007bff;
    --accent-hover: #0056b3;
    --bg-white: #ffffff;
    --bg-light: #f2f2f2;
    --bg-grey: #e0e0e0;
    --border-color: #ccc;
    --border-light: #e5e5e5;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
    --max-width: 1000px;
    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

/* ==================== */
/* Reset & Base Styles */
/* ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    color: var(--primary-color);
    line-height: 1.6;
    font-size: 16px;
    background: var(--bg-white);
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--primary-color);
}

h1 {
    font-size: 2.25rem;
    margin-bottom: 0.5rem;
}

h2 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
}

h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: var(--transition);
}

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

img {
    max-width: 100%;
    height: auto;
    display: block;
}

p {
    margin-bottom: 1rem;
}

/* ==================== */
/* Container */
/* ==================== */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
}

/* ==================== */
/* Navigation */
/* ==================== */
.navbar {
    position: sticky;
    top: 0;
    background: var(--bg-white);
    border-bottom: 1px solid var(--border-light);
    padding: 1rem 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

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

.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

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

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    margin: 0;
}

.nav-link {
    color: var(--secondary-color);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    border-bottom: 2px solid transparent;
    transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-color);
    border-bottom-color: var(--accent-color);
}

/* ==================== */
/* Hero Section */
/* ==================== */
.hero {
    padding: 4rem 0 3rem;
    background: var(--bg-light);
}

.hero-content {
    display: flex;
    gap: 3rem;
    align-items: center;
}

.hero-image {
    flex-shrink: 0;
}

.hero-image img {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--bg-white);
    box-shadow: var(--shadow-md);
}

.hero-text {
    flex: 1;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.125rem;
    color: var(--secondary-color);
    margin-bottom: 0.25rem;
}

.affiliation {
    font-size: 1rem;
    color: var(--secondary-color);
    margin-bottom: 0.25rem;
}

.advisor {
    font-size: 0.95rem;
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
}

.social-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.social-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 8px 16px;
    background: var(--bg-white);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
}

.social-btn i {
    font-size: 1rem;
}

.social-btn:hover {
    background: var(--accent-color);
    color: var(--bg-white);
    border-color: var(--accent-color);
    transform: translateY(-2px);
}

/* ==================== */
/* Sections */
/* ==================== */
.section {
    padding: 4rem 0;
}

.section-alt {
    background: var(--bg-light);
}

.section-title {
    font-size: 1.75rem;
    margin-bottom: 2rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--border-light);
}

/* ==================== */
/* About Section */
/* ==================== */
.about-content {
    max-width: 800px;
}

.about-content p {
    text-align: justify;
    margin-bottom: 1.5rem;
}

.research-interests {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-light);
}

.research-interests h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    display: inline-block;
    padding: 6px 14px;
    background: var(--bg-white);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: var(--transition);
}

.tag:hover {
    background: var(--bg-grey);
}

/* ==================== */
/* Publications Section */
/* ==================== */
.publications-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.publication-card {
    background: var(--bg-white);
    padding: 1.5rem;
    border: 1px solid var(--border-light);
    border-radius: 5px;
    transition: var(--transition);
}

.publication-card:hover {
    border-color: var(--accent-color);
    box-shadow: var(--shadow-md);
}

.publication-card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
    line-height: 1.4;
}

.authors {
    color: var(--secondary-color);
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
}

.venue {
    color: var(--secondary-color);
    font-size: 0.9rem;
    font-style: italic;
    margin-bottom: 1rem;
}

.publication-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.pub-link {
    display: inline-block;
    padding: 6px 14px;
    background: var(--bg-light);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: var(--transition);
}

.pub-link:hover {
    background: var(--accent-color);
    color: var(--bg-white);
    border-color: var(--accent-color);
}

/* ==================== */
/* Experience Section */
/* ==================== */
.experience-container {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.experience-card {
    display: flex;
    gap: 1.25rem;
    align-items: flex-start;
    background: var(--bg-white);
    padding: 1.5rem;
    border: 1px solid var(--border-light);
    border-radius: 5px;
    transition: var(--transition);
}

.experience-card:hover {
    background: var(--bg-light);
    border-color: var(--accent-color);
}

.company-logo {
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-white);
    border: 1px solid var(--border-light);
    border-radius: 8px;
    transition: var(--transition);
    overflow: hidden;
}

.company-logo i {
    font-size: 1.5rem;
    color: var(--secondary-color);
}

.company-logo img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 6px;
}

.company-logo.amazon {
    background: var(--bg-white);
    border-color: var(--border-light);
}

.company-logo.olives {
    background: var(--bg-white);
    border-color: var(--border-light);
}

.experience-card:hover .company-logo {
    transform: scale(1.05);
    box-shadow: var(--shadow-sm);
}

.experience-content {
    flex: 1;
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 2rem;
}

.experience-card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.25rem;
}

.organization {
    color: var(--secondary-color);
    font-size: 0.95rem;
    margin-bottom: 0;
}

.date {
    color: var(--secondary-color);
    font-size: 0.9rem;
    font-weight: 500;
    white-space: nowrap;
}

/* ==================== */
/* Education Section */
/* ==================== */
.education-container {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.education-card {
    display: flex;
    gap: 1.25rem;
    align-items: flex-start;
    background: var(--bg-white);
    padding: 1.5rem;
    border: 1px solid var(--border-light);
    border-radius: 5px;
    transition: var(--transition);
}

.education-card:hover {
    background: var(--bg-white);
    border-color: var(--accent-color);
}

.school-logo {
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-white);
    border: 1px solid var(--border-light);
    border-radius: 8px;
    transition: var(--transition);
    overflow: hidden;
}

.school-logo i {
    font-size: 1.5rem;
    color: var(--secondary-color);
}

.school-logo img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 6px;
}

.school-logo.gatech {
    background: var(--bg-white);
    border-color: var(--border-light);
}

.school-logo.bilkent {
    background: var(--bg-white);
    border-color: var(--border-light);
}

.education-card:hover .school-logo {
    transform: scale(1.05);
    box-shadow: var(--shadow-sm);
}

.education-content {
    flex: 1;
}

.education-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 2rem;
}

.education-card h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.school {
    color: var(--secondary-color);
    font-size: 0.95rem;
    margin-bottom: 0.25rem;
}

.location {
    color: var(--secondary-color);
    font-size: 0.9rem;
    margin-bottom: 0;
}

/* ==================== */
/* Contact Section */
/* ==================== */
.contact-content {
    max-width: 800px;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 2rem;
}

.contact-item {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: 5px;
}

.contact-item h3 {
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
    color: var(--accent-color);
}

.contact-item p {
    margin-bottom: 0.5rem;
    color: var(--secondary-color);
}

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

.contact-item a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

/* ==================== */
/* Footer */
/* ==================== */
.footer {
    background: var(--primary-color);
    color: var(--bg-light);
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

.footer p {
    margin: 0.25rem 0;
    font-size: 0.9rem;
    opacity: 0.9;
}

/* ==================== */
/* Responsive Design */
/* ==================== */
@media (max-width: 768px) {
    .container {
        padding: 0 1.5rem;
    }

    .nav-menu {
        gap: 1.25rem;
        font-size: 0.9rem;
    }

    .hero {
        padding: 3rem 0 2rem;
    }

    .hero-content {
        flex-direction: column;
        text-align: center;
        gap: 2rem;
    }

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

    .hero-image img {
        width: 150px;
        height: 150px;
        margin: 0 auto;
    }

    .social-links {
        justify-content: center;
    }

    .section {
        padding: 3rem 0;
    }

    .section-title {
        font-size: 1.5rem;
    }

    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    .experience-card,
    .education-card {
        flex-direction: row;
    }

    .company-logo,
    .school-logo {
        width: 45px;
        height: 45px;
    }

    .company-logo i,
    .school-logo i {
        font-size: 1.25rem;
    }

    .experience-header,
    .education-header {
        flex-direction: column;
        gap: 0.5rem;
    }

    .date {
        font-size: 0.85rem;
    }

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

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .nav-menu {
        gap: 1rem;
        font-size: 0.85rem;
    }

    .nav-brand {
        font-size: 1.1rem;
    }

    .hero h1 {
        font-size: 1.75rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .publication-card {
        padding: 1.25rem;
    }

    .experience-card,
    .education-card {
        padding: 1rem;
        gap: 1rem;
    }

    .company-logo,
    .school-logo {
        width: 40px;
        height: 40px;
    }

    .company-logo i,
    .school-logo i {
        font-size: 1.1rem;
    }

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

    .social-btn {
        text-align: center;
        justify-content: center;
    }
}