Replace blue button and label classes with primary (#19763)

* make blue really blue

* replace blue button and label classes with primary

* add --color-blue-dark

* add light color variants, tweak a few colors

* fix colors

* add comment

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/features/repo-home.js

@@ -84,8 +84,6 @@ export function initRepoTopicBar() {
       transition: 'horizontal flip',
       duration: 200,
       variation: false,
-      blue: true,
-      basic: true,
     },
     className: {
       label: 'ui small label'