Transform-origin：CSS3 transform
CSS3 transform
transform-origin - CSS
https://developer.mozilla.org
The transform-origin CSS property sets the origin for an element's transformations.
CSS transform
https://www.w3schools.com
The transform-origin property allows you to change the position of transformed elements. 2D transformations can change the x- and y-axis of ...
CSS沒有極限
https://www.casper.tw
當然3D也不例外，如果設定好基準點，物件才能依設定的軸心旋轉，如果把軸心放在最左邊及最右邊，就可以向上方這開門的效果。
CSS
https://kanboo.github.io
就利用變更軸心的位置，再配合transform 來達成。 1
Transform Origin
https://tailwindcss.com
Utilities for specifying the origin for an element's transformations.
CSS讓Box移動了!【Transform篇】
https://ithelp.ithome.com.tw
Transform 變形. 主要是讓目標元素變形，可以旋轉、歪斜、放大、縮小、移動元素有分成2D以及3D的部分，先來介紹. 2D transform. transform-origin 參考點.
Transform
https://css-tricks.com
The transform-origin property is used in conjunction with CSS transforms, letting you change the point of origin of a transform.
transform-origin - SVG
https://developer.mozilla.org
The transform-origin SVG attribute sets the origin for an item's transformations. You can use this attribute with any SVG element. Note ...
"transform-origin"
https://caniuse.com
Can I use provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers.