fix: add background color to html and hide subheader

refactor: limit input size and rename elements array

fix: limit result size

fix: add clear operator

feat: add calculator image

fix: add pointer to img

feat: add responsive design

fix: disable unnecessary rules

fix: block handle count if input is empty

fix: send value to Button

refactor: add handlePM and isElement

fix: add PM value

refactor: add logic to change colors of numbers and operators

feat: remove selection

fix: add margin to signal icon