Tip calculator app (HTML/CSS/JS)

What did you find difficult while building the project?

• Being Newbie/beginner is too hard especially I need to take a lot of trial and error on finding solution on problem.
• CSS Styling, being not quite good on executing/approaching the proper CSS styling and CSS coding.
• Find it so difficult when approaching on media query, so adjusting and choosing CSS style to execute.

Which areas of your code are you unsure of?

• Maybe in my JavaScript have a lot of awkwardness code or not great coding practices.

Do you have any questions about best practices?

• Question: does it good to approach on Mobile design first and next one is Desktop Design or vice versa.
• On learning webdev. please suggests/recommend fast-track roadmap on learning webdev.

Since I'm still on newbie/beginner state. I will give a lot effort on understanding some principles/Technique and expanding knowledge on this web. So feel free to suggest and criticize so I can improve it a lot in this pathway.