CSS compound selector rules and CSS priority Determination

Rules for using CSS compound Selector

1. ID nested class # myid. myclass: <p id = "SP" class = "myclass"> </P>.

2. One element label uses multiple classes .. Important. Warning <P class = "important warning"> be sure not to have spaces. Two classes are supported with spaces.
3. Class elements in the ID label. # Myid. myclass <Div id = "myid"> <P class = "myclass"> </P> </div>
4. class under the element label. P. myclass <p> <SPAN class = "myclass"> </span> </P>
4. ID under the element label. P # myid <p> <span id = "myid"> </span> </P>
5. Element labels under the class. . Myclass span <P class = "myclass"> <span> DD </span> </P>
6. ID label # myid # myid2 <Div id = "myid"> <Div id = "myid2"> </div>. The usage of ID is similar to that of element labels.
7. myclass1. myclass2 indicates that two classes use the same style, rather than nesting. Class can also be nested class. However, if there is no space between the two. myclasses, the two classes are owned at the same time.

8. Element tag nested element tag P span <p> <span> </P>

It's totally different if there are multiple spaces.