diff --git a/modules/primer-base/lib/base.scss b/modules/primer-base/lib/base.scss
index 88213a74aa..8c1bba0458 100644
--- a/modules/primer-base/lib/base.scss
+++ b/modules/primer-base/lib/base.scss
@@ -65,3 +65,12 @@ th {
 button {
   cursor: pointer;
 }
+
+details {
+  summary { cursor: pointer; }
+
+  &:not([open]) {
+    // Set details content hidden by default for browsers that don't do this
+    > *:not(summary) { display: none; }
+  }
+}
diff --git a/modules/primer-buttons/lib/button.scss b/modules/primer-buttons/lib/button.scss
index d31cd625e3..a0d32a596f 100644
--- a/modules/primer-buttons/lib/button.scss
+++ b/modules/primer-buttons/lib/button.scss
@@ -202,3 +202,12 @@
     }
   }
 }
+
+.details-reset {
+  // Remove marker added by the display: list-item browser default
+  > summary { list-style: none; }
+  // Remove marker added by details polyfill
+  > summary::before { display: none; }
+  // Remove marker added by Chrome
+  > summary::-webkit-details-marker { display: none; }
+}