Issue in /src/pages/uxp/reference-spectrum/User Interface/sp-textfield.md

The field seems to appear above all other elements in the UI. I wish there were a way to correctly set its z-index but I've tried and it doesn't seem like it accepts any z-index argument in css or in-line.

Read src/pages/uxp/reference-spectrum/User Interface/sp-textfield.md and compare its guidance with the reported z-index behavior. Confirm whether the field supports CSS or inline z-index settings, then document the supported behavior or limitation on that page; done means the page clearly explains how layering works.

Written by the indexing model from the issue text.