You're setting up decorations for a birthday party and need to figure out exactly how many balloons to buy. Build a single-page balloon planning widget where users enter the room dimensions (length × width in feet), choose a decoration style (light, medium, or dense), and instantly see the recommended number of balloons needed, broken down by type (ceiling floaters, wall clusters, and archway balloons). Users can also add custom balloon color names and assign counts to each color so they know exactly how many of each shade to purchase. All entries should be editable and removable from a tidy list. The final tally — total balloons and per-color breakdown — updates live as inputs change.