Baseline

Underline

Line-through

Underline and line-through

Scenario 1 — Author style set directly on element

UA underline is gone — line-through replaces it (cascade origin wins):

u with text-decoration: line-through

Both lines — must be explicit:

u with text-decoration: underline line-through

Most common real-world case — avoid removing the a underline in epub readers, as there may be no other visual indication of a link:

a with text-decoration: none

Scenario 2 — Decoration set on parent, element is a child

Parent has line-through — child u gets both line-through (propagated) and underline (UA):

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Child text-decoration: none has NO effect on parent propagated line-through:

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