Fixes and improvements on top of the reskin explorer patch (90f7db2):

• Fix invisible text in private badge variant

• Replace undefined –border-radius-xs with –border-radius-sm

• Define –txt-code-semibold and drop –txt-code-bold

• Remove duplicate path in eye-slash icon

• Remove invalid flex-shrink from ActivityDiagram

• Fix alt text in UserAvatar component

• Fix undefined CSS class in RepoAvatar placeholder

• Use semantic color tokens for text and border

Fix repo card layout to prevent description overflow

Replace absolute positioning of activity diagram with flex layout so content and activity sit side by side. Limit description to one line with ellipsis overflow.

Only show node banner when bannerUrl is available

Fix popover clipping inside sidebar overflow

Use position: fixed with computed viewport coordinates so popovers escape the sidebar overflow-y clipping. Remove position: sticky from sidebar as it created a containing block trapping fixed elements.

Revert “Fix popover clipping inside sidebar overflow”

This reverts commit 01f781aad7eea60de17d1124401afd844af6f34f.

Fix sidebar popover clipping

Remove position: sticky and overflow-y: auto from the left sidebar so that popovers inside it are not clipped by the overflow context.

Unify brand colors to blue

Remove green garden brand, make blue the single brand color. Remove desktop brand overrides as they are now redundant.