Add default fontsize using em to the step and content

[octoshrimpy]

By giving the step "header" a class, and giving that class a default font-size of 1.5em, we can change the size of the entire step information by giving .steps-segment a rem font-size. Also could declare default size for all steps by giving .steps a modifier class.

make sure to use bulma's size modifiers for default classes. (.is-small, .is-medium, .is-large)