Replace inline styles and magic-number height calculations with a proper
BEM CSS class system. Attach HeaderCssClass and BodyCssClass to DxPopup
so DevExpress DOM targets can be styled reliably without deep selector
hacks.
Layout changes:
- Remove hardcoded calc(90vh - 114px) height from viewer wrapper; use
flex layout so the body fills available space naturally
- Change overflow on DxPdfViewer wrapper from hidden to auto to allow
horizontal scrolling at high zoom levels
- Center PDF pages horizontally inside dxbrv-document-surface via flex
New CSS classes (BEM):
- .sender-preview-popup root shell, accent top border
- .sender-preview-popup__header styled header via HeaderCssClass
- .sender-preview-popup__body flex column body via BodyCssClass
- .sender-preview-viewer-wrap padding wrapper for the PDF viewer
- .sender-preview-pdf-viewer viewer shell with rounded corners / shadow
- .sender-preview-state-wrap centered container for loading/error states
- .sender-preview-error-card error message card with left accent border
- .sender-preview-error-icon circular icon wrapper
- .sender-preview-error-title/msg typography helpers
Theme support:
- Purple, Blazing Dark variants via data-sf-theme attribute overrides
Custom scrollbars:
- WebKit scrollbar styling scoped to .sender-preview-popup__body
Inline style cleanup in EnvelopeSenderPage.razor:
- Replace all ad-hoc style= attributes with the new CSS classes above