What Css in the value of the box-shadow represent

The following example:

box-shadow:1px 2px 3px 4px color inset;

1px: indicates the length (If negative, compared with the negative direction of the x-axis length) in the positive direction along the x axis;

2px: indicates the length (If negative, compared with the length along the y-axis negative direction) in the positive direction along the y axis;

3px: represents the ambiguity of the shadow, and can only be a positive number;

4px: represents the radius of the extension of the shadow;

color: represents the color of the shadow;

inset: indicates the type of the shadow;