Increase contrast of Button components

src/sidebar/components/test/version-info-test.js

@@ -84,8 +84,7 @@ describe('VersionInfo', function() {
     });
   });
 
-  // FIXME-A11Y
-  it.skip(
+  it(
     'should pass a11y checks',
     checkAccessibility({
       content: () => createComponent(),

src/styles/mixins/buttons.scss

@@ -16,7 +16,7 @@
 @mixin button-base {
   @include reset-native-btn-styles;
   padding: 0.5em;
-  color: var.$grey-5;
+  color: var.$grey-mid;
 
   &__icon {
     width: 16px;
@@ -47,7 +47,7 @@
   border: none;
   background-color: var.$grey-1;
   font-weight: 700;
-  color: var.$grey-5;
+  color: var.$grey-mid;
 
   padding-right: 0.75em;
   padding-left: 0.75em;

src/styles/sidebar/components/button.scss

@@ -29,12 +29,6 @@
   border-radius: 0; // Turn off border-radius to align with <input> edges
   border: 1px solid var.$grey-3;
   border-left: 0px; // Avoid double border with the <input>
-  color: var.$grey-4;
-
-  &:hover {
-    background-color: var.$grey-2;
-    color: var.$grey-5;
-  }
 }
 
 // In a few cases, it's necessary to squeeze buttons into tight spots