Radial progress 圆形进度条

圆形进度条可以用来显示任务的进度，也可以用来显示时间的流逝。

Radial progress needs `--value` CSS variable to work.
To change the size, use `--size` CSS variable which has a default value of `5rem`.
To change the thickness, use `--thickness` CSS variable which is 10% of the size by default.

For radial progress we use <div> instead of <progress> tag because Browsers are unable to show the text inside <progress> tag and Firefox doesn't show the pseudo elements inside <progress> bar at all. For accessibility, a role of 'progressbar' is given to each <div> explicitly, while <progress> receives this role implicitly.