Online calculator with keyboard support (HTML/CSS/JS)

Adaptive calculator with a clean UI and keyboard input support.
All basic functions are implemented plus additional features such as percentages, sign change, and error protection.

Main functionality:
- addition, subtraction, multiplication, division
- decimal number input
- percentage calculations
- sign change (+/-)
- clear (C), delete last character (DEL)
- highlight active operator

Additionally:
- full keyboard support
- visual feedback on press
- responsive layout for different devices
- protection against division by zero

Technologies:
- HTML5
- CSS3 (Flexbox)
- JavaScript (ES6)


#JavaScript #HTML #CSS #frontend #calculator #UI #portfolio #responsive