/* Base Styles & Variables */
:root {
    --color-primary: #2c3e50;
    --color-secondary: #e74c3c;
    --color-accent: #3498db;
    --color-text: #333;
    --color-text-light: #666;
    --color-background: #fff;
    --color-background-alt: #f8f9fa;
    --color-border: #e1e4e8;
    --font-heading: 'Playfair Display', Georgia, serif;
    --font-body: 'Source Sans Pro', -apple-system, BlinkMacSystemFont, sans-serif;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-background);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography */
h1, h2, h3, h4 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-primary);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.125rem; }

p {
    margin-bottom: 1rem;
}

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

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition);
    border: none;
}

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

.btn-primary:hover {
    background-color: #c0392b;
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

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

.btn-large {
    padding: 18px 36px;
    font-size: 1.125rem;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding: 16px 24px;
}

.nav-logo {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-primary);
}

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

.nav-links {
    display: flex;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    color: var(--color-text);
    font-weight: 500;
    font-size: 0.95rem;
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-primary);
    transition: var(--transition);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    padding: 120px 24px 80px;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 60px;
    align-items: center;
}

.hero-image {
    position: relative;
}

.profile-photo {
    width: 280px;
    height: 280px;
    object-fit: cover;
    border-radius: 50%;
    box-shadow: var(--shadow-lg);
    border: 6px solid white;
}

.hero-text h1 {
    margin-bottom: 8px;
    font-size: 3.5rem;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-secondary);
    font-weight: 600;
    margin-bottom: 16px;
}

.hero-tagline {
    font-size: 1.125rem;
    color: var(--color-text-light);
    max-width: 600px;
    margin-bottom: 32px;
}

.hero-cta {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

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

.section-title {
    text-align: center;
    margin-bottom: 48px;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background-color: var(--color-secondary);
    margin: 16px auto 0;
}

/* About Section */
.section-about {
    background-color: var(--color-background);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    font-size: 1.125rem;
}

/* Education Section - Timeline */
.section-education {
    background-color: var(--color-background-alt);
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: var(--color-border);
}

.timeline-item {
    padding-left: 40px;
    padding-bottom: 40px;
    position: relative;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 0;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background-color: var(--color-secondary);
    border: 3px solid var(--color-background-alt);
}

.timeline-date {
    font-size: 0.875rem;
    color: var(--color-secondary);
    font-weight: 600;
    margin-bottom: 8px;
}

.timeline-content h3 {
    margin-bottom: 4px;
}

.timeline-content .institution {
    color: var(--color-text-light);
    font-weight: 500;
    margin-bottom: 8px;
}

/* Experience Section */
.section-experience {
    background-color: var(--color-background);
}

.experience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 32px;
}

.experience-card {
    background-color: var(--color-background-alt);
    padding: 32px;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.experience-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 8px;
    flex-wrap: wrap;
    gap: 8px;
}

.experience-date {
    font-size: 0.875rem;
    color: var(--color-secondary);
    font-weight: 600;
}

.experience-org {
    color: var(--color-text-light);
    margin-bottom: 16px;
}

.experience-details {
    list-style: none;
    padding-left: 0;
}

.experience-details li {
    padding-left: 20px;
    position: relative;
    margin-bottom: 8px;
}

.experience-details li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background-color: var(--color-secondary);
}

/* Research Section */
.section-research {
    background-color: var(--color-background-alt);
}

.research-highlight {
    background-color: var(--color-background);
    padding: 48px;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    margin-bottom: 48px;
}

.research-highlight h3 {
    font-size: 1.75rem;
    margin-bottom: 8px;
}

.research-subtitle {
    color: var(--color-text-light);
    font-style: italic;
    margin-bottom: 24px;
}

.research-findings {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.finding h4 {
    color: var(--color-secondary);
    margin-bottom: 12px;
}

.finding ul {
    padding-left: 20px;
}

.finding li {
    margin-bottom: 8px;
}

.research-other h3 {
    text-align: center;
    margin-bottom: 24px;
}

.research-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 24px;
}

.research-item {
    background-color: var(--color-background);
    padding: 24px;
    border-radius: 8px;
    border-left: 4px solid var(--color-secondary);
}

.research-item h4 {
    margin-bottom: 4px;
}

.research-item p:first-of-type {
    color: var(--color-text-light);
    font-size: 0.875rem;
    margin-bottom: 8px;
}

/* Publications Section */
.section-publications {
    background-color: var(--color-background);
}

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

.publication {
    display: flex;
    gap: 24px;
    padding: 24px 0;
    border-bottom: 1px solid var(--color-border);
}

.publication:last-child {
    border-bottom: none;
}

.publication-year {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-secondary);
    min-width: 80px;
}

.publication-content h3 {
    font-size: 1.125rem;
    margin-bottom: 4px;
}

.publication-content p {
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* Honors Section */
.section-honors {
    background-color: var(--color-background-alt);
}

.honors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 48px;
    max-width: 900px;
    margin: 0 auto;
}

.honors-column h3 {
    margin-bottom: 16px;
    color: var(--color-secondary);
}

.honors-column ul {
    list-style: none;
}

.honors-column li {
    padding: 12px 0;
    border-bottom: 1px solid var(--color-border);
}

.honors-column li:last-child {
    border-bottom: none;
}

/* Interview Section */
.section-interview {
    background: linear-gradient(135deg, var(--color-primary) 0%, #1a252f 100%);
    color: white;
    text-align: center;
}

.section-interview .section-title {
    color: white;
}

.section-interview .section-title::after {
    background-color: var(--color-secondary);
}

.interview-intro {
    max-width: 600px;
    margin: 0 auto 32px;
    font-size: 1.125rem;
    opacity: 0.9;
}

.interview-cta {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.interview-note {
    font-size: 0.875rem;
    opacity: 0.7;
    margin-bottom: 0;
}

/* Contact Section */
.section-contact {
    background-color: var(--color-background);
}

.contact-info {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 48px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.125rem;
}

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

/* Footer */
.footer {
    background-color: var(--color-primary);
    color: white;
    padding: 32px 24px;
    text-align: center;
}

.footer p {
    margin-bottom: 8px;
    opacity: 0.9;
}

.footer-note {
    font-size: 0.875rem;
    opacity: 0.7;
    margin-bottom: 0 !important;
}

/* Responsive Design */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-image {
        margin: 0 auto;
    }

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

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: white;
        flex-direction: column;
        padding: 24px;
        gap: 16px;
        box-shadow: var(--shadow-md);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-toggle {
        display: flex;
    }
}

@media (max-width: 768px) {
    h1 { font-size: 2.25rem; }
    h2 { font-size: 1.75rem; }

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

    .section {
        padding: 60px 0;
    }

    .profile-photo {
        width: 220px;
        height: 220px;
    }

    .research-highlight {
        padding: 32px 24px;
    }

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

    .contact-info {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .btn {
        width: 100%;
        justify-content: center;
    }

    .hero-cta {
        flex-direction: column;
    }

    .timeline::before {
        left: 6px;
    }

    .timeline-item {
        padding-left: 32px;
    }

    .timeline-item::before {
        left: 0;
    }
}