~70 row high

One 、 Row height

Line height refers to the actual height of the text , Can pass line-height To set the row height （ The default is 1.33）

Row height can be specified directly （px,em）, You can also write an integer directly （ Represents the specified multiple of the font ）

Can be Row height Set to and Height The same value , Center single line text vertically in an element

Row height It is also often used to set the line spacing of text （ Row spacing = Row height - font size ）

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Two 、 Font box

Font box Is the lattice where the font exists , Set up font-size Is to set the height of the font box

Row height Will be in Font box Upper and lower average distribution of

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