/* CSS Variables for Theme */
:root {
    --color-primary: #1a1a2e;
    --color-secondary: #16213e;
    --color-accent: #c7956d;
    --color-text: #2d2d2d;
    --color-text-light: #6b6b6b;
    --color-background: #fdfcfb;
    --color-white: #ffffff;
    --color-border: #e8e6e3;
    
    --font-display: 'Cormorant Garamond', serif;
    --font-body: 'Work Sans', sans-serif;
    
    --transition-smooth: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: all 0.6s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

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

html {
    scroll-behavior: smooth;
}

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

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

/* Navigation */
.nav-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
    animation: slideDown 0.6s ease-out;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.nav-wrapper {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-primary);
    text-decoration: none;
    letter-spacing: 0.5px;
    transition: var(--transition-smooth);
}

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

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

.nav-link {
    font-size: 0.95rem;
    color: var(--color-text);
    text-decoration: none;
    font-weight: 400;
    position: relative;
    transition: var(--transition-smooth);
    letter-spacing: 0.3px;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-accent);
    transition: var(--transition-smooth);
}

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 2px;
    background: var(--color-primary);
    transition: var(--transition-smooth);
}

/* Hero Section */
.hero-section {
    margin-top: 90px;
    padding: 5rem 2rem;
    background: linear-gradient(135deg, #fdfcfb 0%, #f8f6f3 100%);
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(199, 149, 109, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    animation: float 8s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    50% { transform: translate(-30px, 30px) rotate(5deg); }
}

.hero-content {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 4rem;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

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

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

.image-placeholder {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    overflow: hidden;
    border: 3px solid var(--color-accent);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
    position: relative;
    background: var(--color-white);
    transition: var(--transition-smooth);
}

.image-placeholder:hover {
    transform: scale(1.05) rotate(2deg);
    box-shadow: 0 25px 70px rgba(0, 0, 0, 0.15);
}

.hero-text {
    flex: 1;
}

.hero-title {
    font-family: var(--font-display);
    font-size: 3.5rem;
    font-weight: 600;
    color: var(--color-primary);
    line-height: 1.2;
    margin-bottom: 1rem;
    letter-spacing: -1px;
}

.title-line {
    display: inline-block;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--color-text-light);
    margin-bottom: 2rem;
    font-weight: 400;
    letter-spacing: 0.3px;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

.hero-divider {
    width: 80px;
    height: 3px;
    background: var(--color-accent);
    animation: expandWidth 0.8s ease-out 0.8s both;
}

@keyframes expandWidth {
    from { width: 0; }
    to { width: 80px; }
}

/* About Section */
.about-section {
    padding: 6rem 2rem;
    background: var(--color-white);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.section-greeting {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 400;
    color: var(--color-primary);
    margin-bottom: 3rem;
    font-style: italic;
}

.bio-text {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.bio-text p {
    font-size: 1.05rem;
    line-height: 1.9;
    color: var(--color-text);
    text-align: justify;
}

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

.text-link {
    color: var(--color-accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: var(--transition-smooth);
}

.text-link:hover {
    border-bottom-color: var(--color-accent);
}

/* Section Titles */
.section-title {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 4rem;
    text-align: center;
    position: relative;
    letter-spacing: -0.5px;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--color-accent);
}

/* Research Section */
.research-section {
    padding: 6rem 2rem;
    background: linear-gradient(135deg, #fdfcfb 0%, #f8f6f3 100%);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2.5rem;
    max-width: 1200px;
    margin: 0 auto;
}

.research-card {
    background: var(--color-white);
    padding: 2.5rem;
    border-radius: 8px;
    border: 1px solid var(--color-border);
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

.research-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 0;
    background: var(--color-accent);
    transition: var(--transition-smooth);
}

.research-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.08);
}

.research-card:hover::before {
    height: 100%;
}

.card-number {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 300;
    color: rgba(199, 149, 109, 0.2);
    margin-bottom: 1rem;
}

.card-title {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 1rem;
}

.card-description {
    color: var(--color-text-light);
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.card-link {
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition-smooth);
}

.card-link:hover {
    gap: 1rem;
}

/* Teaching Section */
.teaching-section {
    padding: 6rem 2rem;
    background: var(--color-white);
}

.teaching-content {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.teaching-item {
    padding: 2rem;
    border-left: 3px solid var(--color-accent);
    background: linear-gradient(135deg, #fdfcfb 0%, transparent 100%);
    transition: var(--transition-smooth);
}

.teaching-item:hover {
    padding-left: 2.5rem;
    background: linear-gradient(135deg, #fdfcfb 0%, #f8f6f3 100%);
}

.teaching-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.teaching-course {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 600;
    color: var(--color-primary);
}

.teaching-term {
    font-size: 0.95rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.teaching-description {
    color: var(--color-text-light);
    line-height: 1.8;
}

/* Experience Section */
.experience-section {
    padding: 6rem 2rem;
    background: linear-gradient(135deg, #fdfcfb 0%, #f8f6f3 100%);
}

.timeline {
    max-width: 900px;
    margin: 0 auto;
    position: relative;
    padding-left: 2rem;
}

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

.timeline-item {
    position: relative;
    padding-left: 3rem;
    padding-bottom: 3rem;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 8px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--color-white);
    border: 3px solid var(--color-accent);
    transition: var(--transition-smooth);
}

.timeline-item:hover::before {
    transform: scale(1.3);
    background: var(--color-accent);
}

.timeline-date {
    font-family: var(--font-display);
    font-size: 1.1rem;
    color: var(--color-accent);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.timeline-title {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.3rem;
}

.timeline-company {
    font-size: 1rem;
    color: var(--color-text-light);
    margin-bottom: 1rem;
    font-weight: 500;
}

.timeline-description {
    color: var(--color-text-light);
    line-height: 1.8;
}

/* Contact Section */
.contact-section {
    padding: 6rem 2rem;
    background: var(--color-white);
}

.contact-content {
    max-width: 800px;
    margin: 0 auto;
}

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

.contact-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.contact-label {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--color-text-light);
    font-weight: 600;
}

.contact-value {
    font-size: 1.1rem;
    color: var(--color-text);
    text-decoration: none;
    transition: var(--transition-smooth);
}

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

.social-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.social-link {
    font-size: 1rem;
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-smooth);
    position: relative;
}

.social-link::after {
    content: '';
    position: absolute;
    bottom: -3px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-accent);
    transition: var(--transition-smooth);
}

.social-link:hover {
    color: var(--color-accent);
}

.social-link:hover::after {
    width: 100%;
}

/* Footer */
.footer {
    background: var(--color-primary);
    color: var(--color-white);
    padding: 3rem 2rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-copyright {
    font-size: 0.9rem;
    opacity: 0.8;
}

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

.footer-link {
    color: var(--color-white);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition-smooth);
    opacity: 0.8;
}

.footer-link:hover {
    opacity: 1;
    color: var(--color-accent);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: 2rem;
        gap: 1.5rem;
        border-top: 1px solid var(--color-border);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero-content {
        flex-direction: column;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .image-placeholder {
        width: 220px;
        height: 220px;
    }
    
    .section-title {
        font-size: 2.2rem;
    }
    
    .research-grid {
        grid-template-columns: 1fr;
    }
    
    .teaching-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .container {
        padding: 0 1.5rem;
    }
}

/* Smooth Scroll Animation */
section {
    opacity: 0;
    animation: fadeIn 0.8s ease-out forwards;
}

@keyframes fadeIn {
    to {
        opacity: 1;
    }
}

section:nth-child(1) { animation-delay: 0s; }
section:nth-child(2) { animation-delay: 0.1s; }
section:nth-child(3) { animation-delay: 0.2s; }
section:nth-child(4) { animation-delay: 0.3s; }