increase contrast of submission_feedback text

common/lib/xmodule/xmodule/css/capa/display.scss

@@ -633,7 +633,7 @@ div.problem {
       // margin-top: 10px;
       display: inline-block;
       margin: 8px 0 0 $baseline/2;
-      color: #777;
+      color: #666;
       font-style: italic;
       -webkit-font-smoothing: antialiased;
     }

common/lib/xmodule/xmodule/css/combinedopenended/display.scss

@@ -828,7 +828,7 @@ section.open-ended-child {
     .submission_feedback {
       display: inline-block;
       margin: 8px 0 0 $baseline/2;
-      color: #777;
+      color: #666;
       font-style: italic;
       -webkit-font-smoothing: antialiased;
     }

lms/static/sass/_shame.scss

@@ -62,13 +62,11 @@
   background: $action-primary-bg;
   color: $action-primary-fg;
 
-  &:hover, &:active {
+  &:hover, &:active, &:focus {
     background: $action-primary-focused-bg;
   }
   &:focus {
-    background: $action-primary-fg;
-    color: $action-primary-focused-bg;
-    outline: 2px solid $action-primary-focused-bg;
+    outline: 2px solid $black;
   }
 
   &.current, &.active {
@@ -98,6 +96,9 @@
   &:hover, &:active, &:focus {
     background: $action-secondary-focused-bg;
   }
+  &:focus {
+    outline: 2px solid $black;
+  }
 
   &.current, &.active {
     box-shadow: inset 0 2px 1px 1px $action-secondary-active-shadow;