I like your builder.... the UI-design is not my cup of tea (white background always irritates me when I am not writing) but it is good and very functional
Two little criticsms though:
- The blue UI-fields for the card info are always present, even if there is not card selected. This give me the expectation that they should be interactive when they are not and distracts from their real purpose as you have no indication wheter or not it is functional. If possilble you could remove them or just let them be a different colour until a card is selected.
- A "Clear all Fields"-Button would be nice, so once you are done building one list you can easily go to building the next one without having to unselect everything by hand)
(on a related note, refreshing the Browser [in this case Firefox] cleared all input but the "faction"-field in the UI stays on your previous selection)