Sheet component's height is not fixed in document demo examples

[declanchiu]

In the documentation example, the component heights of the top and bottom of the sheet component are not fixed.

This caused the pading to fail. Then open devtools and the height will change automatically when the window height changes

[declanchiu]

So this will be very obvious when choosing “sm” size

[declanchiu]

ok, my bad, this bug is incorrect because I realized that this is not a fixed effect.