CSS selector:
-'.' = &&
.class1.class2 {styles} means
the item need to have #both# class1 and class2
,then the styles would be applied, remember there's no space after .class1
-' ' = child of
.class1 .class2{styles} means
with space means class2 should be child of class 1, the style applies
-',' = ||
.class1 , .class2{styles} means
item with class 1 ,class 2 , or class1and class 2
can apply styles
CSS selector: -'.' = && .class1.class2 {styles} means the item need to have #both# class1 and class2 ,then the styles would be applied, remember there's no space after .class1
-' ' = child of .class1 .class2{styles} means with space means class2 should be child of class 1, the style applies
-',' = || .class1 , .class2{styles} means item with class 1 ,class 2 , or class1and class 2 can apply styles