xx-small、x-small、small、medium、large、x-large、xx-large
<!-- xx-small 比 x-small 小一点 -->
<p style="font-size:xx-small">xx-small</p>
<!-- x-small 比 small 小一点 -->
<p style="font-size:x-small">x-small</p>
<!-- small 比 medium 小一点 -->
<p style="font-size:small">small</p>
<!-- medium 是当前字体的默认大小 -->
<p style="font-size:medium">medium</p>
<!-- large 比 medium 大一点 -->
<p style="font-size:large">large</p>
<!-- x-large 比 large 大一点 -->
<p style="font-size:x-large">x-large</p>
<!-- xx-large 比 x-large 大一点 -->
<p style="font-size:xx-large">xx-large</p>显示效果
xx-small
x-small
small
medium
large
x-large
xx-large