Simplify appearance of internal feedback button (#142)

Author: huntie

front_end/ui/legacy/toolbar.css

@@ -569,17 +569,13 @@ devtools-icon.leading-issue-icon {
 [aria-label="[FB-only] Send feedback"] {
   height: 20px;
   padding: 0 4px;
+  border: 1px solid var(--color-details-hairline);
   border-radius: 4px;
-  background: color-mix(in srgb, var(--color-green) 80%, transparent);
+  background: transparent;
 }
 
 [aria-label="[FB-only] Send feedback"]:hover {
-  background: color-mix(in srgb, var(--color-green) 90%, transparent);
-}
-
-[aria-label="[FB-only] Send feedback"] .toolbar-text,
-[aria-label="[FB-only] Send feedback"] .toolbar-glyph {
-  color: white !important;
+  background: color-mix(in srgb, var(--app-color-toolbar-background) 95%, black);
 }
 
 /* [RN] Customise styling for Fusebox's connection status button */