CSS inheritance
In the real world, inheritance means that kids inherit some parents' features and some don't. Likewise, child elements may inherit CSS property values of their parent element, but not always. For example, if you set font color and size for one element, all elements inside of it will inherit those properties unless you apply some styling directly to child elements.
You may feel overwhelmed with all these rules — which properties can inherit and which can't, but you'll start getting it by learning CSS more closely.