How can vertical text be vertically centered?

Sometimes vertical layout is encountered in the work, and it is displayed in the center. This is sometimes used, so I will briefly talk about this 'uncommon' attribute here.

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width:14px;
height:100%;
text-align: center;
writing-mode:vertical-lr;

This is the writing-mode attribute of Zhang Xinxu changing the vertical and horizontal rules of the CSS world. If you want to know more about it, here is a detailed introduction...