There is another syntax for representing RGB values that uses decimal numbers. It looks like this:

h1 {
  color: rgb(23, 45, 23);
}

Here, each of the three values represents a color component, and each can have a decimal number value from 0 to 255. The first number represents the amount of red, the second is green, and the third is blue. These colors are exactly the same as hex, but with a different syntax and a different number system.

In general, hex and decimal color representations are equivalent. Which you choose is a matter of personal taste. That said, it’s good to choose one and be consistent throughout your CSS, because it’s easier to compare hex to hex and decimal to decimal.