Simple Web Calculator Development

I need a lightweight, browser-based calculator that performs the four basic arithmetic operations—addition, subtraction, multiplication and division—without any extra scientific or financial features. A clean, standard interface is all that’s required; no custom graphics or styling beyond straightforward HTML/CSS is necessary.

Core expectations
• Build with vanilla JavaScript (or another lightweight front-end framework if you prefer) so it runs smoothly on all modern desktop and mobile browsers.
• Keep the markup small and semantic; accessibility is a plus.
• Provide clear, commented source files (HTML, CSS, JS) ready for me to drop straight into my site.

I’ll test by loading the page locally and online, checking that each operation returns the correct result and that the calculator handles edge-cases like division by zero gracefully. Once it passes those checks, the project is complete.