Update docs/content/components/box.md
Update docs/content/components/box.md

Co-Authored-By: Mu-An 慕安 <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@muanchiou.com>
primer/primer-css,primer/primer-css,primer/primer,primer/primer-css,primer/primer,primer/primer