归纳最全的CSS2和CSS3区别

大家都知道我们习惯性称作的 CSS3 对于 CSS2.1 有很多的修改和补充。抛开浏览器的兼容性问题，这篇文章把所有的变化整理到一篇文章中便于学习和查阅。尽管我尽量确保收录了所有的新特性，但是不能保证没有遗漏，欢迎大家留言。

下面是CSS3新增的CSS3属性列表。

• animation (and eight associated longhand properties)
• background-clip
• background-origin
• background-size
• border-radius (and four associated longhand properties)
• border-image (and six associated longhand properties)
• box-decoration-break
• box-shadow
• box-sizing
• columns (and thirteen associated multi-column properties)
• clear-after
• flex (and eleven associated flexbox properties)
• font-stretch
• font-size-adjust
• font-synthesis
• font-kerning
• font-variant-caps
• hanging-punctuation
• hyphens
• icon
• image-resolution
• image-orientation
• line-break
• object-fit
• object-position
• opacity
• outline-offset
• overflow-wrap / word-wrap
• backface-visibility
• perspective
• perspective-origin
• pointer-events (for HTML)
• resize
• tab-size
• text-align-last
• text-decoration-line
• text-decoration-skip
• text-decoration-position
• text-decoration-style
• text-emphasis (and three associated properties)
• text-justify
• text-orientation
• text-overflow
• transform
• transform-style
• text-shadow
• transition (and four associated longhand properties)
• word-break
• word-spacing
• writing-mode