/* CSS Variables for easy customization */
:root {
    --primary-color: #2563eb;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --background: #ffffff;
    --sidebar-bg: #f9fafb;
    --border-color: #e5e7eb;
    --hover-bg: #f3f4f6;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text-primary);
    line-height: 1.7;
    background: var(--background);
}

/* Sidebar Navigation */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 280px;
    height: 100vh;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    padding: 3rem 2rem;
    overflow-y: auto;
    z-index: 100;
}

.nav-content {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.site-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.site-subtitle {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    font-weight: 400;
}

.nav-links {
    list-style: none;
    margin-bottom: auto;
}

.nav-links li {
    margin-bottom: 0.5rem;
}

.nav-links a {
    display: block;
    padding: 0.5rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 0.5rem;
    font-weight: 500;
    transition: all 0.2s;
}

.nav-links a:hover {
    background: var(--hover-bg);
    color: var(--text-primary);
}

.nav-links a.active {
    background: var(--primary-color);
    color: white;
}

.social-links {
    display: flex;
    gap: 1rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.social-links a {
    color: var(--text-secondary);
    transition: color 0.2s;
}

.social-links a:hover {
    color: var(--primary-color);
}

/* Main Content */
.main-content {
    margin-left: 280px;
    padding: 4rem 6rem;
    max-width: 1200px;
}

.section {
    margin-bottom: 5rem;
}

.section h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
}

.section h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.section-intro {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.8;
}

/* About Section */
.profile-header {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.profile-img {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--border-color);
}

.position {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-top: 0.5rem;
}

.about-content p {
    margin-bottom: 1.25rem;
    color: var(--text-secondary);
}

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

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

.interests {
    margin-top: 2.5rem;
    padding: 2rem;
    background: var(--sidebar-bg);
    border-radius: 0.75rem;
}

.interest-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.75rem;
    list-style: none;
}

.interest-list li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
}

.interest-list li:before {
    content: "•";
    color: var(--primary-color);
    font-weight: bold;
    margin-right: 0.75rem;
}

/* Research Section */
.research-areas {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.research-card {
    padding: 1.5rem;
    background: var(--sidebar-bg);
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
    transition: all 0.2s;
}

.research-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
}

.research-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.research-card p {
    color: var(--text-secondary);
}

/* Publications Section */
.publication-category {
    margin-bottom: 3rem;
}

.publication-category h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

.publication {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: 1.5rem;
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

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

.pub-year {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.pub-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

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

.pub-authors strong {
    color: var(--text-primary);
}

.pub-venue {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
}

.pub-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.pub-links a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0.25rem 0.75rem;
    border: 1px solid var(--primary-color);
    border-radius: 0.375rem;
    transition: all 0.2s;
}

.pub-links a:hover {
    background: var(--primary-color);
    color: white;
}

/* Teaching Section */
.teaching-block {
    margin-bottom: 3rem;
}

.course {
    padding: 1.5rem;
    background: var(--sidebar-bg);
    border-radius: 0.75rem;
    margin-bottom: 1.5rem;
    border: 1px solid var(--border-color);
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.course h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

.course-term {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
}

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

.course-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    transition: all 0.2s;
}

.course-link:hover {
    gap: 0.5rem;
}

.previous-courses {
    list-style: none;
}

.previous-courses li {
    padding: 0.75rem 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.previous-courses li:last-child {
    border-bottom: none;
}

.teaching-philosophy {
    padding: 2rem;
    background: var(--sidebar-bg);
    border-radius: 0.75rem;
    border-left: 4px solid var(--primary-color);
}

.teaching-philosophy p {
    color: var(--text-secondary);
}

/* Contact Section */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.contact-item h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.contact-item p {
    color: var(--text-secondary);
    line-height: 1.8;
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

/* Footer */
.footer {
    margin-top: 5rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-content {
        padding: 3rem 4rem;
    }
}

@media (max-width: 768px) {
    .sidebar {
        position: relative;
        width: 100%;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        padding: 2rem;
    }

    .nav-links {
        display: flex;
        flex-wrap: wrap;
        gap: 0.5rem;
        margin-bottom: 1.5rem;
    }

    .nav-links li {
        margin-bottom: 0;
    }

    .main-content {
        margin-left: 0;
        padding: 2rem 1.5rem;
    }

    .section h2 {
        font-size: 1.75rem;
    }

    .profile-header {
        flex-direction: column;
        text-align: center;
    }

    .profile-img {
        width: 120px;
        height: 120px;
    }

    .quick-links {
        flex-direction: column;
    }

    .publication {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .research-areas {
        grid-template-columns: 1fr;
    }

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

@media (max-width: 480px) {
    .main-content {
        padding: 1.5rem 1rem;
    }

    .section {
        margin-bottom: 3rem;
    }

    .course-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* Print Styles */
@media print {
    .sidebar {
        display: none;
    }

    .main-content {
        margin-left: 0;
        padding: 0;
    }

    .section {
        page-break-inside: avoid;
    }
}