Use the font color for alternative-highlighted background on quick add menu

frontend/src/app/modules/common/header/quick-add-menu.sass

@@ -1,3 +1,7 @@
+$background: var(--button--alt-highlight-background-color)
+$background-hover: var(--button--alt-highlight-background-hover-color)
+$color: var(--button--alt-highlight-font-color)
+
 .op-quick-add-menu
   @include breakpoint(680px down)
     display: none
@@ -6,15 +10,12 @@
     display: flex
     justify-content: center
     align-items: center
-    border: 2px solid var(--header-item-font-color)
     border-radius: 50%
     width: 26px
     height: 26px
     padding: 1px 8px 0 8px
-    background: var(--button--alt-highlight-background-color)
-    border-color: var(--button--alt-highlight-background-color)
+    @include button-style($background, $background-hover, $color)
 
   &:hover &
     &--icon::before
       background: var(--button--alt-highlight-background-hover-color)
-      border-color: var(--button--alt-highlight-background-hover-color)