body { font-family: "Helvetica Neue", Arial, sans-serif; line-height: 1.8; margin: 40px; color: #333; } h1, h2, h3 { color: #2c3e50; } a { color: #2980b9; text-decoration: none; } a:hover { text-decoration: underline; } .toc { background: #f9f9f9; padding: 20px; border-left: 4px solid #2980b9; margi…