Fix for vanguard.com (#8835)
Fix for vanguard.com (#8835)

* Fix for vanguard.com

Inversions for:
- Dark menu chevrons
- Dark magnifying glass search icons
- Light text on light background buy/sell transaction buttons

* Add inversion for unreadable HoldingDetailForm buttons
darkreader/darkreader,darkreader/darkreader,darkreader/darkreader