Adjust navbar button styling to lighten color when hovered
Adjust navbar button styling to lighten color when hovered

Using the new 'lighten' parameter, the button variants for navbar buttons are now styled to become lighter-colored on hover.

Also demonstrating named parameters for @mixin parameters. Does this make reading the SCSS easier to parse?

gios-asu/ASU-Web-Standards-Bootstrap,gios-asu/ASU-Web-Standards-Bootstrap