accordion avec bug

angular.json

package-lock.json

package.json

src/app/app.component.html

src/app/app.module.ts

src/app/change-page/change-page.component.html

src/app/stage-accordion/stage-accordion.component.html

src/app/stage-detail/stage-detail.component.css

src/app/stage-detail/stage-detail.component.html

src/app/stage-detail/stage-detail.component.spec.ts

src/app/stage-detail/stage-detail.component.ts

src/index.html