fix: Don't add bslib-gap-spacing when card body is not fillable

NEWS.md

@@ -20,6 +20,8 @@
 
 * The main content area of `page_sidebar()` and `page_navbar()` with a `sidebar` now have a minimum height and width to avoid squashed content in fillable layouts. The minimum height and width are controllable via Sass and CSS variables (see the pull requests for details). (#1057, #1059)
 
+* When `card_body(fillable = FALSE)`, bslib now preserves flow-layout margin bottom settings. (#1073)
+
 # bslib 0.7.0
 
 This large release includes many improvements and bug fixes for newer UI components like `layout_columns()`, `card()`, and `sidebar()`. In addition, the new `input_task_button()` offers a drop-in replacement for `shiny::actionButton()` (to prevent multiple submissions of the same operation) as well as pairing nicely with the new `shiny::ExtendedTask` for implementing truly non-blocking operations in Shiny.

R/card.R

@@ -197,7 +197,8 @@ card_body <- function(..., fillable = TRUE, min_height = NULL, max_height = NULL
   }
 
   tag <- div(
-    class = "card-body bslib-gap-spacing",
+    class = "card-body",
+    class = if (fillable) "bslib-gap-spacing",
     style = css(
       min_height = validateCssUnit(min_height),
       "--bslib-card-body-max-height" = validateCssUnit(max_height),

R/layout.R

@@ -389,7 +389,8 @@ row_heights_css_vars <- function(x) {
 grid_item_container <- function(el, ..., fillable = TRUE) {
   div(
     ...,
-    class = "bslib-grid-item bslib-gap-spacing",
+    class = "bslib-grid-item",
+    class = if (fillable) "bslib-gap-spacing",
     if (fillable) as_fillable_container(),
     el
   )