This is a solution to the Calculator app challenge on Frontend Mentor. Frontend Mentor challenges help you improve your coding skills by building realistic projects.

• Overview
  • The challenge
  • Screenshot
  • Links
• My process
  • Built with
  • What I learned
  • Continued development
• Author
• Acknowledgments

Users should be able to:

• See the size of the elements adjust based on their device's screen size
• Perform mathmatical operations like addition, subtraction, multiplication, and division
• Adjust the color theme based on their preference
• Bonus: Have their initial theme preference checked using prefers-color-scheme (done) and have any additional changes saved in the browser (not done yet)

• Solution URL: github-repository
• Live Site URL: Live Site on netlify

• Semantic HTML5 markup
• SCSS
• Flexbox
• CSS Grid
• JavaScript

• using emmet to write repetitive markup quickly

• ::before and ::after pseudo-elements will stay above its parent element beside their z-idexes

  • to cover one pseudo-element you'll need another
  • selecting them for animation is weird

• using css custom properties in sacc functions doesn't work

  • it might with sass interpolation(#{} - syntax), but I didn't figure out how
  • using filter: brightness() instead

• selector by tag attribute ([data-val="something"])

• setting the height of the body/main wrapping element depending on viewport height resulted in strange renderings

  • used JavaScript to set height on window.innerHeight

• switching color themes by declaring css classes full of custom properties and adding it to the body via JS

• listening to keypress and keyup events and mapping them to functions

• figuring out how to solve a chain of arithmetic operations in the right order

• reading the result of a css media query via js: (window.matchMedia("(prefers-color-scheme: dark)"))

• writing cleaner SCSS - using more mixins and variables
• writing cleaner JS by encapsulating data and functions
• still not comfortable with forms and input elements

Stephan Ullmann

• Frontend Mentor - @stephanullmann

I learned so much from the courses of Jonas Schmedtmann.