fix: details marker safari (#3179)

Author: eirikbacker

.changeset/chilled-ravens-rush.md

@@ -0,0 +1,5 @@
+---
+"@digdir/designsystemet-css": patch
+---
+
+**Details:** Hide native `<summary>` arrow in Safari

packages/css/src/details.css

@@ -35,7 +35,12 @@
     --dsc-details-border-color: var(--ds-color-border-subtle);
   }
 
-  & :is(summary, u-summary) {
+  /* Hide default marker in Safari */
+  & > summary::-webkit-details-marker {
+    display: none;
+  }
+
+  & > :is(summary, u-summary) {
     color: var(--dsc-details-summary-color);
     align-items: center;
     background: var(--dsc-details-summary-background);