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button replace elements.
And according to the CSS 2.1 specification ,
This specification does not fully define the interaction: before and: after replacing elements (for example, IMG in HTML). This will be described in more detail in future specifications.
But the current draft of level 3 selectors only says
The :: before and :: after pseudo-elements can be used to describe the created content before or after the content of an element. They are explained in CSS 2.1.
Therefore, using :before or :after elements on a button will produce unreliable results.
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