css-----样式表继承

CSS样式表继承指的是，特定的CSS属性向下传递到子孙元素。

可以继承的css样式：

azimuth, border-collapse, border-spacing,
caption-side, color, cursor, direction, elevation,
empty-cells, font-family, font-size, font-style,
font-variant, font-weight, font, letter-spacing,
line-height, list-style-image, list-style-position,
list-style-type, list-style, orphans, pitch-range,
pitch, quotes, richness, speak-header, speaknumeral,
speak-punctuation, speak, speechrate,
stress, text-align, text-indent, texttransform,
visibility, voice-family, volume, whitespace,
widows, word-spacing

（1.文本font相关属性2.列表list相关属性3.color）

Font-size的子类继承的不是实际值，而是计算后的值。