Web page css in *{margin:0; padding:0;} What's the use?

*  This thing is called a wildcard to match all the elements on the page.
*{margin:0; padding:0;} Like 2L said, body, UL, Li, P,h1~h6,dd,dt, etc... has a default margin or padding value,
With this sentence you can remove the browser these default values, and the following settings. (Note: Not without it, just convenient)

You add the sentence after the page chaos, it is of course, because you do not have the overtime is based on the default margin or padding set, remove the default value, of course, will be messy.
Do how One, is not add *{margin:0; padding:0;} The second is to recalculate the margin or padding value yourself and redesign

Suggest the second kind, after all for the sake of later.

How to call DIV.MEINV alone with *{margin:0; padding:0;}

Add it directly behind the DIV.MEINV.
DIV.MEINV *{margin:0; padding:0;}
This means that the values of margin and padding for all elements under match DIV.MEINV are 0.
However, if you add *{margin:0 to the front; padding:0;}  This sentence, there is no need to add on the DIV.MEINV ...

Web page css in *{margin:0; padding:0;} What's the use?