/* ===============================================
   PROFESSOR WEBSITE - CSS STYLESHEET
   =============================================== */

/* ===== ROOT VARIABLES ===== */
:root {
    --primary-color: #2C3E50;
    --secondary-color: #E74C3C;
    --accent-color: #3498DB;
    --text-color: #333;
    --text-light: #666;
    --bg-light: #F8F9FA;
    --white: #FFFFFF;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
}

/* ===== RESET & BASE STYLES ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Open Sans', sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Playfair Display', serif;
    font-weight: 700;
    line-height: 1.3;
}

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

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

/* ===== UTILITY CLASSES ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-padding {
    padding: 80px 0;
}

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

/* ===== NAVIGATION ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: var(--white);
    box-shadow: var(--shadow);
    z-index: 1000;
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    font-family: 'Playfair Display', serif;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
    align-items: center;
}

.nav-link {
    color: var(--text-color);
    font-weight: 600;
    font-size: 0.95rem;
    padding: 8px 0;
    position: relative;
}

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

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

.btn-cv {
    background: var(--accent-color);
    color: var(--white);
    padding: 10px 25px;
    border-radius: 25px;
    font-weight: 600;
}

.btn-cv:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

/* Hamburger Menu */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    transition: var(--transition);
}

/* ===== HERO SECTION ===== */
.hero {
    height: 50vh;
    min-height: 500px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-color) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    color: var(--white);
    text-align: center;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 2.5rem;
    margin-bottom: 15px;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 10px;
}

.hero-institution {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-bottom: 40px;
}

.btn {
    padding: 12px 30px;
    border-radius: 30px;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
}

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

.btn-primary:hover {
    background: var(--secondary-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

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

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

.social-links {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.social-links a {
    width: 45px;
    height: 45px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.social-links a:hover {
    background: var(--white);
    color: var(--primary-color);
    transform: translateY(-5px);
}

.scroll-down {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 2rem;
    color: var(--white);
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(10px); }
}

/* ===== SECTION HEADERS ===== */
.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-title {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.title-underline {
    width: 80px;
    height: 4px;
    background: var(--accent-color);
    margin: 0 auto 20px;
}

.section-description {
    font-size: 1.1rem;
    color: var(--text-light);
    max-width: 700px;
    margin: 0 auto;
}

/* ===== ABOUT SECTION ===== */
.about-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 50px;
    align-items: start;
}

.about-image img {
    width: 100%;
    border-radius: 15px;
    box-shadow: var(--shadow-lg);
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-top: 30px;
}

.stat-item {
    background: var(--primary-color);
    color: var(--white);
    padding: 20px;
    border-radius: 10px;
    text-align: center;
}

.stat-item h3 {
    font-size: 2rem;
    margin-bottom: 5px;
}

.stat-item p {
    font-size: 0.9rem;
}

.about-text h3 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.about-text p {
    margin-bottom: 20px;
    line-height: 1.8;
}

.expertise, .education {
    margin-top: 30px;
}

.expertise h4, .education h4 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.expertise-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.expertise-list li {
    display: flex;
    align-items: center;
    gap: 10px;
}

.expertise-list i {
    color: var(--accent-color);
}

.education-item {
    margin-bottom: 15px;
}

.education-item h5 {
    font-size: 1.1rem;
    color: var(--text-color);
    margin-bottom: 5px;
}

.education-item p {
    color: var(--text-light);
}

/* ===== RESEARCH SECTION ===== */
.research-areas {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.research-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.research-icon {
    width: 80px;
    height: 80px;
    background: var(--accent-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin: 0 auto 20px;
}

.research-card h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.research-card p {
    color: var(--text-light);
    line-height: 1.7;
}

/* ===== PUBLICATIONS SECTION ===== */
.publications-list {
    max-width: 900px;
    margin: 0 auto;
}

.publication-item {
    display: flex;
    gap: 30px;
    margin-bottom: 30px;
    padding-bottom: 30px;
    border-bottom: 1px solid #E0E0E0;
}

.pub-year {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-color);
    min-width: 60px;
}

.pub-content {
    flex: 1;
}

.pub-title {
    font-size: 1.2rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.pub-authors {
    color: var(--text-light);
    margin-bottom: 8px;
}

.pub-venue {
    color: var(--text-light);
    margin-bottom: 10px;
}

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

.pub-link {
    color: var(--accent-color);
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 5px;
}

.pub-link:hover {
    color: var(--secondary-color);
}

/* Metrics Section */
.metrics-section {
    margin-top: 60px;
    text-align: center;
}

.metrics-section h3 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 30px;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    max-width: 800px;
    margin: 0 auto;
}

.metric-card {
    background: var(--white);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
}

.metric-card i {
    font-size: 3rem;
    color: var(--accent-color);
    margin-bottom: 15px;
}

.metric-card h4 {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 10px;
}

.metric-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

/* ===== TEACHING SECTION ===== */
.subsection-title {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 30px;
}

.course-card {
    background: var(--white);
    padding: 30px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.course-header h4 {
    font-size: 1.3rem;
    color: var(--primary-color);
}

.course-level {
    background: var(--accent-color);
    color: var(--white);
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.course-level.graduate {
    background: var(--secondary-color);
}

.course-description {
    color: var(--text-light);
    line-height: 1.7;
}

.supervision-section {
    margin-top: 50px;
}

.supervision-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.supervision-card {
    background: var(--white);
    padding: 40px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    text-align: center;
}

.supervision-card i {
    font-size: 3rem;
    color: var(--accent-color);
    margin-bottom: 20px;
}

.supervision-card h4 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.supervision-card p {
    color: var(--text-light);
}

/* ===== CONTACT SECTION ===== */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 50px;
}

.contact-card {
    background: var(--bg-light);
    padding: 25px;
    border-radius: 10px;
    margin-bottom: 20px;
}

.contact-card i {
    font-size: 2rem;
    color: var(--accent-color);
    margin-bottom: 15px;
}

.contact-card h4 {
    font-size: 1.2rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.contact-card p, .contact-card a {
    color: var(--text-light);
    line-height: 1.7;
}

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

/* Contact Form */
.contact-form {
    background: var(--bg-light);
    padding: 40px;
    border-radius: 15px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 15px;
    border: 1px solid #DDD;
    border-radius: 8px;
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-color);
}

.btn-block {
    width: 100%;
}

/* ===== FOOTER ===== */
.footer {
    background: var(--primary-color);
    color: var(--white);
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 30px;
}

.footer-col h4 {
    font-size: 1.3rem;
    margin-bottom: 20px;
}

.footer-col ul {
    list-style: none;
}

.footer-col li {
    margin-bottom: 10px;
}

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

.footer-social {
    display: flex;
    gap: 15px;
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* ===== SCROLL TO TOP ===== */
.scroll-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--accent-color);
    color: var(--white);
    border: none;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
}

.scroll-top.show {
    opacity: 1;
    visibility: visible;
}

.scroll-top:hover {
    background: var(--secondary-color);
    transform: translateY(-5px);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 992px) {
    .about-content,
    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .metrics-grid,
    .supervision-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-social {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    /* Mobile Navigation */
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow);
        transform: translateX(-100%);
        transition: var(--transition);
    }
    
    .nav-menu.active {
        transform: translateX(0);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .expertise-list {
        grid-template-columns: 1fr;
    }
    
    .about-stats {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    .section-padding {
        padding: 50px 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .research-areas {
        grid-template-columns: 1fr;
    }
}