anyone know grid-template-columns: repeat(3, 1fr); what does 1fr do?

Question

I just tried to change the value but nothing happened, I just want to understand what it does.

Answer 1

This code will make column repeat 3 times making 3 equal parts each size 1fr.

Fr is fraction.
If you have 1 column size 1fr it will be 100%,
If you have 2 columns each size 1fr, each will take 50% of full row.(100% / 2)

Fr make equal parts similar as percentage, except fr include gap in calculations where percentage does not.

Here is more about is, with code examples;
https://css-tricks.com/introduction-fr-css-unit/