Document styles do not enter the shadow tree

Expected: the shadow box below is plain — no red dashed border, no strike-through, no red outline, no italics — even though it contains elements matching .box, p.inner and #target.

The light-DOM reference below it does get all of that, proving the rules themselves work.

Shadow styles do not leak out

Expected: the shadow box is green-on-yellow; the paragraph after it stays black-on-white despite matching the shadow tree's p { ... } rule.

light paragraph after the component — must be plain black on white

!important does not cross either

Expected: still no red dashed border on the shadow box — !important raises cascade priority but does not change which elements a document rule can match.