In a web map, I can rotate the basemap to a freehand angle by right-clicking the map, holding, and dragging. That works, but it's fiddly to get a map with grid-shaped roads rotated into a perfectly vertical orientation.
This idea is to rotate the map to a known angle instead, by entering something like 18.5 degrees using the keyboard.
Related AGOL question: How to rotate web map to specific angle?