New features
* Added new fast-scrolling data table and data grid outputs. (538)
* Added `include_js()` and `include_css()`, for easily including JS and CSS files in an application. (127)
* Added sidebar, card, value box, and accordion methods into `shiny.experimental.ui`. (481)
* Added `fill` and `fillable` methods into `shiny.experimental.ui`. If `fill` is `True`, then the UI component is allowed to expand into the parent container. If `fillable` is `True`, then the UI component will allow its content to expand. Both `fill` on the child component and `fillable` on the parent component must be `True` for the child component to expand. (481)
* Added sidebar methods into `shiny.experimental.ui`. `shiny.experimental.ui.layout_sidebar()` does not require `ui.panel_main()` and `ui.panel_sidebar()`. These two methods have been deprecated. `x.ui.page_navbar()`, `x.ui.navset_bar()`, `x.navset_tab_card()`, and `x.navset.pill_card()` added `sidebar=` support. (481)
* feat(sidebar): `ui.layout_sidebar()` internally uses `x.ui.layout_sidebar()`, enabling filling layout features. (568)
Bug fixes
* Fixed 496: Previously, when `shiny run --reload` was used, the app would only reload when a .py file changed. Now it will reload when .py, .css, .js, and .html files change. (505)
* Closed 535: Added a meta viewport tag, so that page layout will adapt to mobile device screens. (540)