diff --git a/frontend/packages/dashboard/src/common.css b/frontend/packages/dashboard/src/common.css
index ac4f238e..7d8513a8 100644
--- a/frontend/packages/dashboard/src/common.css
+++ b/frontend/packages/dashboard/src/common.css
@@ -108,6 +108,11 @@ code {
   text-transform: uppercase;
   letter-spacing: 0.1em;
   background: transparent;
+  /* Strip browser UA button chrome (solid fill, system text colour).
+     Without this, native <button> + <input type="submit"> elements
+     ignore our background:transparent and colour in some browsers. */
+  -webkit-appearance: none;
+  appearance: none;
   border: 1px solid;
   padding: 0.25em 0.8em;
   cursor: pointer;