Firefox doesn't yet support the CSS3 pseudo-elements: : value, : : repeat-item, and: : repeat-index.

Firefox不支持css3伪元素：value、： repeat - item和：repeat - index。

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An inspirational collection of experimental link effects mostly using transitions on pseudo-elements.

使用转换和伪元素实现链接特效的非常有意义的文档。

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Pseudo-elements are similar to pseudo-classes (and share syntax with them) but define content within the document. Pseudo-elements defined by the CSS2 Recommendation include

伪元素与伪类相似（语法也相同），但它定义的是文档中的内容。

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