Merge pull request #371 from primer/muan/details

Add .details-reset

modules/primer-base/lib/base.scss

@@ -67,3 +67,12 @@ button {
   // Remove border radius added by Chroma macOS
   border-radius: 0;
 }
+
+details {
+  summary { cursor: pointer; }
+
+  &:not([open]) {
+    // Set details content hidden by default for browsers that don't do this
+    > *:not(summary) { display: none; }
+  }
+}

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; }
+}