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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #2d3748;
    background-color: #f7fafc;
}

.layout {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 280px;
    background: #ffffff;
    border-right: 1px solid #e2e8f0;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    z-index: 100;
}

.sidebar-header {
    padding: 2rem 1.5rem 1rem;
    border-bottom: 1px solid #e2e8f0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.sidebar-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.sidebar-subtitle {
    font-size: 0.875rem;
    opacity: 0.9;
    font-weight: 300;
}

.sidebar-nav {
    padding: 1.5rem 0;
}

.nav-section {
    margin-bottom: 1.5rem;
}

.nav-section-title {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #718096;
    padding: 0 1.5rem;
    margin-bottom: 0.5rem;
}

.nav-link {
    display: block;
    padding: 0.75rem 1.5rem;
    color: #4a5568;
    text-decoration: none;
    font-size: 0.875rem;
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.nav-link:hover {
    background-color: #edf2f7;
    color: #2d3748;
    border-left-color: #667eea;
}

.nav-link.active {
    background-color: #ebf4ff;
    color: #3182ce;
    border-left-color: #3182ce;
    font-weight: 500;
}

/* Main content */
.main-content {
    flex: 1;
    margin-left: 280px;
    padding: 2rem 3rem;
    max-width: calc(100vw - 280px);
}

.page-header {
    margin-bottom: 2rem;
}

.page-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #1a202c;
    margin-bottom: 0.5rem;
}

.page-subtitle {
    font-size: 1.125rem;
    color: #718096;
}

.content-section {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
    border: 1px solid #e2e8f0;
}

.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 1rem;
}

.about-text {
    color: #4a5568;
    margin-bottom: 1.5rem;
}

.research-goals {
    background: #f0fff4;
    border: 1px solid #9ae6b4;
    border-radius: 6px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.goals-title {
    color: #22543d;
    font-weight: 600;
    margin-bottom: 1rem;
}

.goals-list {
    color: #2f855a;
    margin-left: 1.25rem;
}

.goals-list li {
    margin-bottom: 0.5rem;
}

/* Posts */
.post-card {
    border-bottom: 1px solid #e2e8f0;
    padding: 1.5rem 0;
    transition: all 0.2s;
}

.post-card:last-child {
    border-bottom: none;
}

.post-card:hover {
    background: #f7fafc;
    margin: 0 -1rem;
    padding: 1.5rem 1rem;
    border-radius: 6px;
}

.post-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.75rem;
    font-size: 0.875rem;
    color: #718096;
}

.post-date {
    font-weight: 500;
}

.post-category {
    background: #edf2f7;
    color: #4a5568;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
}

.post-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #2d3748;
    text-decoration: none;
    margin-bottom: 0.75rem;
    display: block;
}

.post-title:hover {
    color: #3182ce;
}

.post-excerpt {
    color: #4a5568;
    line-height: 1.6;
}

.demo-embed {
    background: #f8f9fa;
    border: 2px dashed #dee2e6;
    padding: 2rem;
    text-align: center;
    border-radius: 6px;
    margin: 1rem 0;
    color: #6c757d;
    font-style: italic;
}

/* Feedback section */
.feedback-section {
    background: #ebf8ff;
    border: 1px solid #90cdf4;
    border-radius: 6px;
    padding: 1.5rem;
    margin: 2rem 0;
}

.feedback-title {
    color: #2c5282;
    font-weight: 600;
    margin-bottom: 1rem;
}

.feedback-button {
    background: #3182ce;
    color: white;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: background-color 0.2s;
}

.feedback-button:hover {
    background: #2c5282;
}

/* Mobile responsiveness */
.mobile-menu-btn {
    display: none;
    position: fixed;
    top: 1rem;
    left: 1rem;
    z-index: 200;
    background: #667eea;
    color: white;
    border: none;
    padding: 0.5rem;
    border-radius: 4px;
    cursor: pointer;
}

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }
    
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
        padding: 1rem;
        max-width: 100vw;
    }
    
    .page-title {
        font-size: 2rem;
    }
}

/* Content sections for different pages */
.content-page {
    display: none;
}

.content-page.active {
    display: block;
}