I have two content types in place—one that stores an individual workout step and another that stores the workout itself as an ordered list of those steps. Now I need a clean, intuitive form that lets me build a complete workout on a single page with expandable sections. Where I’m stuck: • Nesting is the main pain-point. A step can itself be a “repeat” block that contains more steps, so the form needs to call itself recursively without breaking the layout. • I tried drupal/inline_entity_form, but it ruins the visual structure and becomes hard to follow once the nesting begins. What I want instead: • A single-page interface where users can add, edit, reorder, and delete steps through expandable panels/fieldsets—no page reloads or multi-step wizards. • Support for several step variations: simple timed or distance steps, steps that trigger conditional logic, and more complex, multi-field blocks. All of them must be creatable inline and tied exclusively to the parent workout (never reused elsewhere). • A “repeat” step that opens its own sub-list of steps and can be expanded or collapsed just like a normal step. Ideally this should be unlimited-depth but at minimum one level of nesting must work reliably. Deliverables 1. Custom Drupal form (Form API or another stable approach) that meets the interface goals above and keeps the layout intact during nesting. 2. Any custom modules, templates, or libraries required, installed and configured in a way that can be moved between environments. 3. Brief hand-off notes so I can extend field definitions or add new step types later. 4. Compatibilty with the designed Drupal entities in https://github.com/jrv/run_workout If you have a proven strategy for elegant nested entity forms in Drupal—especially on a single, expandable page—let’s make this happen.