One em is the width and height of one “m” character (using whatever font size a website is set to).

1em正好是一个“m”字符的宽度和高度(而无论你的网站使用多大的字号)。

youdao

One em is the width and height of one “m” character (using whatever font size a website is set to).

1em正好是一个“m”字符的宽度和高度(而无论你的网站使用多大的字号)。

youdao