Use flexbox to position and space dashboard panes

modules/core/ui/dashboard/css/dashboard_layout.css

@@ -1,8 +0,0 @@
-.layout--twocol .layout__region {
-  box-sizing: border-box;
-  overflow-x: scroll;
-}
-
-.layout--twocol .layout__region--first {
-  padding-right: 1.5em;
-}

modules/core/ui/dashboard/farm_ui_dashboard.libraries.yml

@@ -1,4 +0,0 @@
-dashboard_layout:
-  css:
-    theme:
-      css/dashboard_layout.css: { }

modules/core/ui/dashboard/src/Controller/DashboardController.php

@@ -185,8 +185,6 @@ class DashboardController extends ControllerBase {
     // Build the layout.
     $render = $layoutInstance->build($regions);
 
-    // Add the dashboard_layout styles.
-    $render['#attached']['library'][] = 'farm_ui_dashboard/dashboard_layout';
     return $render;
   }
 

modules/core/ui/theme/css/dashboard.css

@@ -0,0 +1,23 @@
+/* Add a gap between layout regions. */
+.layout--twocol {
+  --dashboard-spacing: var(--gin-spacing-s);
+  gap: var(--dashboard-spacing);
+}
+
+/* Use flexbox within each region. */
+.layout--twocol .layout__region,
+.layout--twocol .layout__region {
+  flex-basis: 100%;
+  display: flex;
+  flex-direction: column;
+  gap: var(--dashboard-spacing);
+}
+
+/* Split first and second regions to two columns on large screens. */
+@media (min-width: 48em) {
+  .layout--twocol .layout__region--first,
+  .layout--twocol .layout__region--second {
+    flex-basis: 50%;
+    max-width: calc(50% - var(--dashboard-spacing)*.5);
+  }
+}

modules/core/ui/theme/farm_ui_theme.libraries.yml

@@ -2,6 +2,10 @@ asset_map_popup:
   css:
     theme:
       css/asset_map_popup.css: { }
+dashboard:
+  css:
+    theme:
+      css/dashboard.css: { }
 flag:
   css:
     theme:

modules/core/ui/theme/farm_ui_theme.module

@@ -109,6 +109,13 @@ function farm_ui_theme_preprocess_log__full(&$variables) {
   $variables['#attached']['library'][] = 'farm_ui_theme/layout';
 }
 
+/**
+ * Implements hook_preprocess_HOOK().
+ */
+function farm_ui_theme_preprocess_page__dashboard(&$variables) {
+  $variables['#attached']['library'][] = 'farm_ui_theme/dashboard';
+}
+
 /**
  * Implements hook_preprocess_HOOK().
  */