Updated the `DxPopup` component in `CreateEnvelopeWizardPopup.razor` to use `90vw` for both width and max-width, replacing the previous values of `860px` and `96vw`. Corresponding changes were made in `sender-page.css` for `.sender-create-wizard-popup .dxbl-popup` under the media query for screens with a max width of `760px`. These changes improve layout consistency and responsiveness.