- Fix cart overlay blocking header in mobile (z-index: header 900 < cart 1000)
- Add cart-is-collapsed class with translateY(calc(100% - 60px)) for bottom sheet behavior
- Ensure cart header remains visible and clickable when collapsed in mobile
- Add deep Vuetify styles for search field integration (:deep(.v-field))
- Preserve desktop sticky sidebar behavior (position: sticky, overflow-y: auto)
- Make entire cart header clickable in mobile (@click on v-card-title)
- Add visual feedback with chevron icons (mdi-chevron-up/down)
- Clean CSS organization with section comments