Project Grade: Enhancement + Metadata

GRADED PROJECT CHECKPOINT — finish your Documentation Hub: (1) a 'copy install command' affordance as progressive enhancement — a <details> disclosure containing the command in a <code> block (readable without JS) plus a button inside it with popovertarget-less text 'Copy' marked aria-label="Copy install command"; (2) hreflang alternates for en and vi pointing at https://docs.example.com/en/ and /vi/ paths; (3) a <meta name="robots"> that allows indexing.

Difficulty: advanced