Tailwind css, vanilla css and Javascript

The design looks ok, I just have some things to point regarding the functionality;

• This is a calculator so the inputs should only be restricted to numbers, not letters and everything that comes with the keyboard.
• I can enter negative numbers and it does the calculation anyways.
• On the select tip % you have 10$ instead of 10%.
• & I think the math is some kind of incorrect ;

1. let's say the bill is $20 there's 4 people and I pick a tip of 25%, it gives me total/person of $3... that's way off. 4 * 3 = 12, there's no way that is going to cover a $20 bill.
2. Haven't done this challenge, but I think you are supposed to take the bill which is 20$ in this case and divide it with the number of people, which is 4 in this case, so it'll be 20 / 4 = 5 each person is to pay $5 plus the tip of 25%, which is 20 * 0.25 = 5 and divide the 5 by 4 = 1.25 so each person is going to pay $6.25 when the tip is included.

• And I may be wrong but I think that's how everything is supposed to work.