Custom checkboxes & input fixes

#72

Content box & modal background variables

#71

Update exports to work with JS

#68

Code block name & language, anchor component

#66

Spaced group component

#65

Fix content box header meta

#64

Content box padding fix

#63

Configurable button styles

#62

Change ModalCloseIcon styles

#61

Solid containers

Allow defining the background color of containers that are set to solid

#60