Web programing

Question

This is the general question for web programming.
How do we know what attributes in html or properties in css do we need to set? Do we need to know all browsers defaults? For example why don't we write everywhere font-style: normal. Why are we sure that all browsers default option is exactly "normal"?

Answer 1

Because default font style is normal no need to to add font-style: normal; there are many CSS browser support differences , You can use SASS to make this CSS browser support code easy as SASS auto generate different browser CSS code
https://www.w3schools.com/cssref/css3_browsersupport.asp