:root { 
    --primary-dark: #0f172a; 
    --accent: #2563eb; 
}

body { 
    background-color: #f8fafc; 
    font-family: 'Inter', sans-serif; 
}

.sidebar { 
    background: white; 
    border-right: 1px solid #e2e8f0; 
    min-height: 100vh; 
    position: fixed; 
    padding-top: 20px; 
    z-index: 100; 
}

.nav-link { 
    color: #64748b; 
    font-weight: 500; 
    padding: 12px 20px; 
    border-radius: 8px; 
    margin-bottom: 5px; 
}

.nav-link.active { 
    background: #eff6ff; 
    color: var(--accent); 
}

.CodeMirror { 
    height: 500px; 
    border-radius: 8px; 
    font-size: 14px; 
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1); 
}

.output-box { 
    background: #1e293b; 
    color: #f8fafc; 
    padding: 20px; 
    border-radius: 8px; 
    min-height: 250px; 
    font-family: 'Fira Code', 'Courier New', monospace; 
    white-space: pre-wrap; 
    font-size: 14px; 
}

.btn-run { 
    background: var(--accent); 
    border: none; 
    padding: 10px 25px; 
    font-weight: 600; 
    transition: 0.3s; 
}

.btn-run:hover { 
    background: #1d4ed8; 
    transform: translateY(-1px); 
}