/* ===== BASE STYLES ===== */
:root {
    --primary-color: #3a5a78;
    --secondary-color: #718eaa;
    --accent-color: #f8c630;
    --text-color: #333333;
    --light-text: #777777;
    --bg-light: #f8f9fa;
    --bg-dark: #243447;
    --white: #ffffff;
    --transition: all 0.3s ease;
    --box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

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

html {
    scroll-behavior: smooth;
}

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

h1, h2, h3, h4 {
    font-family: 'Playfair Display', serif;
    margin-bottom: 0.5rem;
    line-height: 1.2;
}

h1 {
    font-size: 2.5rem;
    font-weight: 600;
}

h2 {
    font-size: 2rem;
    font-weight: 500;
}

h3 {
    font-size: 1.5rem;
    font-weight: 500;
}

h4 {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--secondary-color);
}

p {
    margin-bottom: 1rem;
    color: var(--text-color);
}

ul {
    list-style: none;
}

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

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section-padding {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: var(--accent-color);
}

#research .section-title::after {
    background: #f8c630;
    height: 4px;
    width: 60px;
}

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

.mt-5 {
    margin-top: 3rem;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 500;
    font-size: 0.85rem;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

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

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

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    margin-left: 0.5rem;
}

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

/* ===== NAVBAR ===== */
#navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: var(--white);
    box-shadow: var(--box-shadow);
    padding: 1rem 0;
    transition: var(--transition);
}

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

.name {
    font-family: 'Playfair Display', serif;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
}

.nav-links li {
    margin-left: 1.5rem;
}

.nav-links a {
    font-size: 0.9rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    position: relative;
    padding-bottom: 3px;
}

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

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

.nav-links a.active {
    color: var(--accent-color);
}

.menu-btn {
    font-size: 1.5rem;
    cursor: pointer;
    display: none;
}

/* ===== HERO SECTION ===== */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(to right, rgba(255,255,255,0.9), rgba(255,255,255,0.7)), url('../images/hero-bg.jpg');
    background-size: cover;
    background-position: center;
    padding-top: 80px;
}

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

.hero-text {
    flex: 1;
}

.hero-text h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.hero-text h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--secondary-color);
}

.hero-text p {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
    max-width: 600px;
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

.placeholder-img {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    overflow: hidden;
    border: 8px solid var(--white);
    box-shadow: var(--box-shadow);
}

.placeholder-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* ===== EDUCATION SECTION ===== */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    width: 2px;
    background-color: var(--secondary-color);
    top: 0;
    bottom: 0;
    left: 10px;
}

.timeline-item {
    position: relative;
    margin-bottom: 2.5rem;
    padding-left: 40px;
}

.timeline-item::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background-color: var(--accent-color);
    left: 1px;
    top: 5px;
    z-index: 1;
}

.timeline-content {
    padding: 1.5rem;
    background-color: var(--white);
    box-shadow: var(--box-shadow);
    border-radius: 5px;
    position: relative;
}

.timeline-date {
    font-style: italic;
    color: var(--light-text);
    margin-bottom: 0.8rem;
}

/* ===== RESEARCH SECTION ===== */
.research-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    max-width: 960px;
    margin: 0 auto;
    padding-top: 20px;
}

.research-item {
    background-color: var(--white);
    padding: 2.5rem 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    text-align: center;
    transition: all 0.3s ease;
    width: 300px;
    max-width: 300px;
    margin: 0;
    flex: 0 0 auto;
}

.research-item:hover {
    transform: translateY(-5px);
}

.research-icon {
    font-size: 2.5rem;
    color: #476685;
    margin-bottom: 1rem;
}

.research-item h3 {
    margin-bottom: 0.8rem;
    color: #333;
    font-size: 1.3rem;
}

.research-item p {
    color: #555;
    line-height: 1.5;
    font-size: 0.95rem;
}

.projects {
    margin-top: 2rem;
}

.project {
    background-color: var(--white);
    padding: 1.5rem;
    border-radius: 5px;
    box-shadow: var(--box-shadow);
    margin-bottom: 1.5rem;
}

.project-info {
    color: var(--light-text);
    font-style: italic;
    margin-bottom: 0.8rem;
}

/* ===== PUBLICATIONS SECTION ===== */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.publication-item {
    background-color: var(--white);
    padding: 1.5rem;
    border-radius: 5px;
    box-shadow: var(--box-shadow);
    border-left: 4px solid var(--primary-color);
}

.authors {
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.journal {
    color: var(--light-text);
    margin-bottom: 0.8rem;
}

.publication-link {
    display: inline-block;
    margin-top: 0.5rem;
    font-weight: 500;
}

.publication-link i {
    margin-left: 0.3rem;
    font-size: 0.8rem;
}

/* ===== EXPERIENCE SECTION ===== */
#experience .timeline-item ul {
    margin-top: 0.8rem;
    padding-left: 1.2rem;
    list-style-type: disc;
}

#experience .timeline-item li {
    margin-bottom: 0.5rem;
}

/* ===== SKILLS SECTION ===== */
.skills-container {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    justify-content: space-between;
}

.skills-category {
    flex: 1;
    min-width: 250px;
}

.skills-category h3 {
    margin-bottom: 1rem;
    position: relative;
    padding-left: 1.5rem;
}

.skills-category h3::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 10px;
    height: 10px;
    background-color: var(--accent-color);
    border-radius: 50%;
}

.skills-category ul {
    padding-left: 1.5rem;
}

.skills-category li {
    margin-bottom: 0.8rem;
    position: relative;
    padding-left: 1rem;
}

.skills-category li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
}

/* ===== CONTACT SECTION ===== */
.contact-container {
    display: flex;
    gap: 2rem;
}

.contact-info, .contact-form {
    flex: 1;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 1.5rem;
}

.contact-item i {
    font-size: 1.2rem;
    color: var(--primary-color);
    margin-right: 1rem;
    margin-top: 0.3rem;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: var(--white);
    font-size: 1.2rem;
    transition: var(--transition);
}

.social-link:hover {
    background-color: var(--accent-color);
    color: var(--text-color);
    transform: translateY(-3px);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 2px rgba(113, 142, 170, 0.2);
}

/* ===== FOOTER ===== */
footer {
    background-color: var(--bg-dark);
    color: var(--white);
    padding: 2rem 0;
    text-align: center;
}

footer p {
    color: var(--white);
    margin-bottom: 0.5rem;
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 992px) {
    .hero-content {
        flex-direction: column;
        text-align: center;
    }
    
    .hero-text h1 {
        font-size: 2.5rem;
    }
    
    .hero-text p {
        margin: 0 auto 1.5rem auto;
    }
    
    .contact-container {
        flex-direction: column;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--white);
        flex-direction: column;
        align-items: center;
        padding: 1rem 0;
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-links li {
        margin: 0.8rem 0;
    }
    
    .menu-btn {
        display: block;
    }
    
    .skills-container {
        flex-direction: column;
    }
}

@media (max-width: 576px) {
    .section-padding {
        padding: 3rem 0;
    }
    
    h1 {
        font-size: 2.2rem;
    }
    
    .hero {
        height: auto;
        padding: 100px 0 60px;
    }
    
    .placeholder-img {
        width: 200px;
        height: 200px;
    }
    
    .research-grid {
        flex-direction: column;
        align-items: center;
        gap: 30px;
    }
    
    .research-item {
        width: 90%;
        max-width: 350px;
    }
}